Page 1 of 326

6560-50-P

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 60 

[EPA-HQ-OAR-2009-0734; FRL-9920-50-OAR]

RIN 2060-AP93 

Standards of Performance for New Residential Wood Heaters, New Residential 

Hydronic Heaters and Forced-Air Furnaces

AGENCY: Environmental Protection Agency.

ACTION: Final rule. 

SUMMARY: The Environmental Protection Agency (EPA) is taking final action to 

revise the Standards of Performance for New Residential Wood Heaters and to add a new 

subpart: Standards of Performance for New Residential Hydronic Heaters and Forced-Air 

Furnaces. Today’s rule is authorized by section 111(b) and section 114 of the Clean Air 

Act (CAA). The EPA is not finalizing, at this time, the proposed Standards of 

Performance for New Residential Masonry Heaters in order to allow additional time for

the Masonry Heater Association to finish their efforts to develop revised test methods, an 

emissions calculation program and an alternative dimensioning standard. This final rule 

achieves several objectives for new residential wood heaters, including applying updated 

emission limits that reflect the current best systems of emission reduction; eliminating 

exemptions over a broad suite of residential wood combustion devices; strengthening test 

methods as appropriate; and streamlining the certification process. Residential wood 

smoke emissions are a significant national air pollution problem and human health issue. 

These emissions occur in many neighborhoods across the country, including minority and 

low-income neighborhoods, and impact people in their homes. To the extent that children 
Page 2 of 326

and other sensitive populations are particularly susceptible to asthma, and that minority 

populations and low-income populations are more vulnerable, this rule will significantly 

reduce the pollutants that adversely affect their health. On an economic basis, the public 

benefits of this rule vastly outweigh the costs, with every dollar in additional cost 

producing more than $100 in public benefit. This final action does not include any 

requirements for heaters solely fired by gas, oil or coal. In addition, it does not include 

any new requirements associated with appliances that are already in use. The EPA 

continues to strongly encourage state, local, tribal, industry and consumer efforts to 

change out (replace) older heaters with newer, cleaner, more efficient heaters. Additional 

information is on the EPA Burn Wise web site at www.epa.gov/burnwise. Also, we 

encourage state, local, and tribal authorities to develop site-specific installation and 

operating requirements to help ensure healthy air for all. 

DATES: This final action is effective on [INSERT DATE 60 DAYS AFTER DATE 

OF PUBLICATION IN THE FEDERAL REGISTER]. The incorporation by 

reference of certain publications listed in this rule is approved by the Director of the 

Federal Register as of [INSERT DATE OF PUBLICATION IN THE FEDERAL 

REGISTER].

ADDRESSES: The EPA has established a docket for this action under Docket ID 

Number EPA-HQ-OAR-2009-0734. All documents in the docket are listed in the 

http://www.regulations.gov index. Although listed in the index, some information is not 

publicly available (e.g., confidential business information or other information whose 

disclosure is restricted by statute). Certain other material, such as copyrighted material, 

will be publicly available only in hard copy form. Publicly available docket materials are 
Page 3 of 326

available either electronically at http://www.regulations.gov or in hard copy at the EPA 

Docket Center, Public Reading Room, EPA WJC West, Room 3334, 1301 Constitution 

Ave., NW, Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30 

p.m., Monday through Friday, excluding legal holidays. The telephone number for the 

Public Reading Room is (202) 566-1744, and the telephone number for the Air Docket is 

(202) 566-1742.

FOR FURTHER INFORMATION CONTACT: For questions about this final rule for 

new residential wood heaters, hydronic heaters, and forced-air furnaces, contact Ms. 

Amanda Aldridge, Office of Air Quality Planning and Standards, Outreach and 

Information Division (C304-05), U.S. Environmental Protection Agency, Research 

Triangle Park, North Carolina 27711, telephone number (919) 541-5268; fax number 

(919) 541-2664; email address: aldridge.amanda@epa.gov.

SUPPLEMENTARY INFORMATION: 

Acronyms and Abbreviations. The following acronyms and abbreviations are used 

in this document:

μg/m3 Micrograms per cubic meter

ASTM American Society for Testing and Materials (now ASTM International)

BSER Best System of Emissions Reduction

BTU British Thermal Unit

CAA Clean Air Act

CBI Confidential Business Information

CDX Central Data Exchange

CEDRI Compliance and Emissions Data Reporting Interface

CFR Code of Federal Regulations

CO Carbon Monoxide

CO2 Carbon Dioxide

CSA Canadian Standards Association

EPA U.S. Environmental Protection Agency

ERT Electronic Reporting Tool

EJ Environmental Justice

FR Federal Register
Page 4 of 326

g/hr Grams per hour

HAP Hazardous Air Pollutant(s)

HPBA Hearth, Patio and Barbecue Association

IBR Incorporation by Reference

ICR Information Collection Request

ISO International Organization for Standardization

lb Pound(s)

lb/hr Pound(s) per hour

lb/mmBtu Pound(s) per million British Thermal Units

NAAQS National Ambient Air Quality Standards

NAICS North American Industry Classification System

NESCAUM Northeast States for Coordinated Air Use Management

NESHAP National Emission Standards for Hazardous Air Pollutants

NOx Nitrogen Oxides

NSPS New Source Performance Standards

NTTAA National Technology Transfer and Advancement Act of 1995

NYSERDA New York State Energy Research and Development Authority

OAQPS Office of Air Quality Planning and Standards (U.S. EPA)

OECA Office of Enforcement and Compliance Assurance (U.S. EPA)

OMB Office of Management and Budget

PAH Polycyclic Aromatic Hydrocarbon

PFI Pellet Fuels Institute

POM Polycyclic Organic Matter

PM Particulate Matter

PM2.5 Particulate Matter with an aerodynamic diameter of 2.5 micrometers or 

less (“fine particles”)

ppm Parts per million

R&D Research and Development

RIA Regulatory Impact Analysis

RTC Response to Comments

U.S. United States

U.S.C. United States Code

UMRA Unfunded Mandates Reform Act

vs. Versus

VCS Voluntary Consensus Standard(s)

VOC Volatile Organic Compound

yr Year(s)

Response to Comments (RTC) Document. On February 3, 2014 (79 FR 6330), the 

EPA proposed revisions to the Standards of Performance for New Residential Wood 

Heaters based on the EPA’s review of these standards. On July 1, 2014 (79 FR 37259), 

the EPA published a Notice of Data Availability (NODA) that solicited comment on 
Page 5 of 326

additional information regarding residential wood heater testing using cord wood and 

emissions by burn rate excerpted from EPA certification test reports. In this action, we 

are finalizing revisions to the rule, as well as Standards of Performance for New 

Residential Hydronic Heaters and Forced-Air Furnaces. A document summarizing the 

public comments on the proposal and the NODA and the EPA responses to the significant 

comments is available in Docket ID Number EPA-HQ-OAR-2009-0734. A summary of 

responses to the major comments is in section V.

Organization of this Document. The following outline is provided to aid in locating 

information in this preamble. 

I. General Information

A. Executive Summary

B. Does this Action Apply to Me?

C. Where Can I Get a Copy of this Document?

D. Judicial Review

II. Background Information for this Final Rule

A. What is the NSPS Program?

B. Why is Residential Wood Smoke a Concern?

III. Summary of the Final Rule

A. General

B. Room Heaters (revised subpart AAA)

C. Central Heaters: Hydronic Heaters and Forced-Air Furnaces (subpart QQQQ)

IV. Summary of Significant Changes Following Proposal

A. Best Systems of Emission Reduction/Particulate Emission Limits

B. Appliance Certification, Laboratory Accreditation and Third-party Certification

C. Cost and Economic Impacts

D. Test Methods and Compliance Certification Calculation Procedures 

E. Sell-through of Inventory

F. Appeals and Administrative Hearing Procedures 

V. Summary of Responses to Major Comments

A. BSER and Particulate Emission Limits for Room Heaters (revised subpart AAA)

B. BSER and Particulate Emission Limits for Central Heaters (subpart QQQQ)

C. Appliance Certification

D. Laboratory Accreditation, Third-party Certification and Administrative Approval 

Process

E. Costs and Economic Impacts

F. Test Methods

G. Health Effects and Benefits
Page 6 of 326

VI. Summary of Environmental, Cost, Economic, and Non-Air Health and Energy 

Impacts

A. What are the Air Quality Impacts?

B. What are the Benefits?

C. What are the Cost Impacts?

D. What are the Economic Impacts?

E. What are the Non-air Quality Health and Energy Impacts?

VII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 

13563: Improving Regulation and Regulatory Review

B. Paperwork Reduction Act (PRA)

C. Regulatory Flexibility Act (RFA)

D. Unfunded Mandates Reform Act (UMRA)

E. Executive Order 13132: Federalism

F. Executive Order 13175: Consultation and Coordination with Indian Tribal 

Governments

G. Executive Order 13045: Protection of Children from Environmental Health Risks 

and Safety Risks

H. Executive Order 13211: Actions Concerning Regulations that Significantly Affect 

Energy Supply, Distribution, or Use

I. National Technology Transfer and Advancement Act

J. Executive Order 12898: Federal Actions to Address Environmental Justice in 

Minority Populations and Low-Income Populations

K. Congressional Review Act

I. General Information 

A. Executive Summary

The purpose of this action is to finalize amendments to the Standards of 

Performance for New Residential Wood Heaters (40 CFR part 60, subpart AAA) and to 

add one new subpart: Standards of Performance for New Residential Hydronic Heaters 

and Forced-Air Furnaces (40 CFR part 60, subpart QQQQ). This final action was 

developed following a CAA section 111(b)(1)(B) review of the 1988 promulgated 

subpart AAA (53 FR 5860, February 26, 1988), i.e., the 1988 New Source Performance 

Standards (NSPS). Section 111 requires the EPA to establish standards based on best 

systems of emission reduction (BSER). Section 111(b) requires emission standards for 

affected sources and section 111(h)(2)(B) allows the EPA to establish work practices and 
Page 7 of 326

operational standards or combinations of standards in certain cases, such as when testing 

is impractical due to technological or economic limitations. The current body of evidence 

strongly supports revision of the 1988 NSPS to capture the technology improvements and 

enhanced performance of such units since 1988 and to expand the applicability of these 

standards to include additional wood-burning residential heating devices that are 

available today. Section 111 requires the EPA to consider costs and economic impacts. 

The potential impact on this industry that is comprised of over 90 percent small 

businesses was a concern to the EPA, and we have minimized these potential impacts to 

the degree possible while still achieving significant emission reductions. For example, we 

have incorporated stepped (phased) emission limits and streamlined certification 

procedures to ease the transition. The health benefits associated with these regulations are 

substantially greater than the cost to manufacture cleaner, lower-emitting appliances. In 

fact, the public health benefits of this rule outweigh the costs by more than 100 times.

As discussed in the preamble to the February 3, 2014, proposed rule, particulate 

pollution from wood heaters is a significant national air pollution problem and human 

health issue. Residential wood smoke contains fine particles with an aerodynamic 

diameter of 2.5 micrometers or less (PM2.5), carbon monoxide (CO), volatile organic 

compounds (VOC), toxic air pollutants (e.g., benzene and formaldehyde), and climateforcing emissions (e.g., methane and black carbon). Residential wood smoke can 

contribute to unhealthy levels of PM2.5 in many neighborhoods nationwide, including in 

minority and low-income neighborhoods, and impact people in their homes. To the extent 

that children and other sensitive populations are particularly susceptible to asthma, and 

that minority populations and low-income populations are more vulnerable to the effects 
Page 8 of 326

of air pollution, this rule will significantly reduce the pollutants that adversely affect their 

health.

Populations that are at greater risk for experiencing health effects related to fine 

particle exposures include older adults, children and individuals with pre-existing heart or 

lung disease. Each year, smoke from wood heaters produces hundreds of thousands of 

tons of fine particles throughout the country – mostly during the winter months. 

Nationally, residential wood combustion accounts for 44 percent of total stationary and 

mobile polycyclic organic matter (POM) emissions, which account for nearly 25 percent 

of all area source air toxics cancer risks and 15 percent of noncancer respiratory effects.1

Residential wood smoke causes many counties in the U.S. to either exceed the EPA’s 

health-based national ambient air quality standards (NAAQS) for fine particles or places 

them on the cusp of exceeding those standards.2 To the degree that older, higher emitting, 

less efficient wood heaters are replaced by newer heaters that meet the requirements of 

this rule, these requirements for cleaner new stoves will result in substantial reductions in 

emissions, and thus in exposure, producing reduced health impacts. A summary of the 

estimated health benefits is shown in Table 1 below. More details are in the final 

Regulatory Impact Analysis (RIA) in the docket for this rule.

Consistent with Executive Order 13563, “Improving Regulation and Regulatory 

Review,” we have estimated the cost and benefits of the final rule. The estimated annual 

 

1

Strategies for Reducing Residential Wood Smoke. EPA-456/B-13-001, March 2013. 

Prepared by Outreach and Information Division, Air Quality Planning Division, Office of 

Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research 

Triangle Park, NC 27711. pp. 4-5.

2 Air Quality and Emissions Data; Supporting Information for the Residential Wood 

Heater New Source Performance Standard, August 14, 2013.
Page 9 of 326

net benefits at a 3-percent discount rate are $3.4 billion to $7.6 billion, and $3.1 billion to 

$6.9 billion at a 7-percent discount rate in 2013 dollars. The net benefits estimate reflects 

8,269 tons of PM2.5 emission reductions per year, and a total annualized cost of $45.7

million, producing an unusually large net benefit for this rule of more than 100 times the 

costs, and even greater net benefits coming from the new rule applied to single burn rate 

stoves. We estimate that this rule will result in 360 (Krewski, et. al., 2009) or 810

(Lepeule, et. al., 2012) avoided premature deaths per year. The non-monetized benefits 

include 46,000 tons of CO reductions per year; 9,300 tons of VOC reductions per year; 

reduced exposure to hazardous air pollutants (HAP), including formaldehyde, benzene, 

and polycyclic organic matter (POM); reduced climate effects due to reduced black 

carbon emissions and reduced greenhouse gases emissions; reduced ecosystem effects; 

and reduced visibility impairments. Table 1 is a summary of the results of the analysis per 

type of residential wood heater. We have provided estimates reflecting average annual 

impacts for the 2015 to 2020 timeframe, which are the implementation years analyzed in 

the RIA for this final rule.

Table 1. Summary of Compliance Costs, Monetized Benefits, and Monetized Net 

Benefits (2013 dollars) by Type of Heater in the 2015–2020 Time Frame for the 

Final Rule

Type of Heater

Total Annualized 

Costs

($ millions)

Monetized Benefits

($ millions)a, b

Monetized Net 

Benefits

($ millions)

Wood stoves $ 3.02 $14 to $31 $11 to $28

Single burn rate stoves $ 0.87 $280 to $630 $280 to $630

Pellet stoves $ 1.52 $ 2 to $5 $0 to $3

Forced-air furnaces $ 15.36 $1,700 to $3,700 $1,700 to $3,700

Hydronic heating 

systems

$24.88 $1,400 to $3,200 $1,400 to $3,200
Page 10 of 326

a All estimates are for the time frame from 2015 to 2020 inclusive. These results include 

units anticipated to come online and the lowest cost disposal assumption. Total 

annualized costs shown in this table are estimated at a 7-percent interest rate to be 

consistent with guidance from the Office of Management and Budget (OMB). Total

annualized costs are also estimated at a 3 percent interest rate for each source category

to be consistent with OMB guidance, and these costs are about 13 percent less than the 

total annualized costs presented in this table. These costs are presented in the RIA and 

in the cost memoranda for this final rule. The monetized net benefits with total 

annualized costs at a 3 percent interest rate are minimally different than those 

calculated with total annualized costs at a 7 percent interest rate. 

b Total monetized benefits are estimated at a 3-percent discount rate. The total monetized 

benefits reflect the human health benefits associated with reducing exposure to PM2.5 

through reductions of directly emitted PM2.5. It is important to note that the monetized 

benefits include many but not all health effects associated with PM2.5 exposure. 

Benefits are shown as a range from Krewski et al. (2009) to Lepeule et al. (2012). 

These models assume that all fine particles, regardless of their chemical composition, 

are equally potent in causing premature mortality because the scientific evidence is not 

yet sufficient to allow differentiation of effect estimates by particle type. Because these 

estimates were generated using benefit-per-ton estimates, we do not break down the 

total monetized benefits into specific components.

B. Does this Action Apply to Me?

Table 2 of this preamble lists categories and entities that will be regulated by this 

action. Table 2 is not intended to be exhaustive, but rather provides a guide for readers 

regarding entities likely to be affected by this final action. These standards, and any 

changes considered in this rulemaking, are directly applicable to sources as a federal 

program. Other federal, state, local and tribal government entities are not directly affected 

by this final action. States may decide to request partial delegation of enforcement of 

some parts of this rule, e.g., ensuring permanent labels are on new heaters in retail stores. 

Table 2. Regulated Entities

Category NAICSa Code Examples of Regulated 

Entities
Page 11 of 326

Residential Wood 

Heating

333414 - Heating Equipment 

(except Warm Air Furnaces) 

Manufacturing

Manufacturers, owners and 

operators of wood heaters, 

pellet heaters/stoves and 

hydronic heaters

333415 - Air-Conditioning and 

Warm Air Heating Equipment 

and Commercial and Industrial 

Refrigeration Equipment 

Manufacturing

Manufacturers, owners and 

operators of forced-air 

furnaces

Testing Laboratories 541380 - Testing Laboratories 

(except Medical, Veterinary)

Testers of wood heaters, 

pellet heaters/stoves and 

hydronic heaters

aNorth American Industry Classification System

C. Where Can I Get a Copy of this Document?

In addition to being available in the docket, an electronic copy of this final rule, is 

posted at the following address: http://www2.epa.gov/residential-wood-heaters. 

D. Judicial Review

Under section 307(b)(1) of the Clean Air Act (CAA), judicial review of these 

final rules is available only by filing a petition for review in the United States Court of 

Appeals for the District of Columbia Circuit by November 13, 2012. Under section 

307(b)(2) of the CAA, the requirements established by these final rules may not be 

challenged separately in any civil or criminal proceedings brought by the EPA to enforce 

these requirements. Section 307(d)(7)(B) of the CAA further provides that ‘‘[o]nly an 

objection to a rule or procedure which was raised with reasonable specificity during the 

period for public comment (including any public hearing) may be raised during judicial 

review.’’ This section also provides a mechanism for us to convene a proceeding for 

reconsideration, ‘‘[i]f the person raising an objection can demonstrate to the EPA that it 

was impracticable to raise such objection within [the period for public comment] or if the 

grounds for such objection arose after the period for public comment (but within the time 
Page 12 of 326

specified for judicial review) and if such objection is of central relevance to the outcome 

of the rule.’’ Any person seeking to make such a demonstration to us should submit a 

Petition for Reconsideration to the Office of the Administrator, U.S. EPA, Room 3000, 

1200 Pennsylvania Ave. NW., Washington, DC 20460, with a copy to both the person(s) 

listed in the preceding FOR FURTHER INFORMATION CONTACT section, and the 

Associate General Counsel for the Air and Radiation Law Office, Office of General 

Counsel (Mail Code 2344A), U.S. EPA, 1200 Pennsylvania Ave. NW., Washington, DC 

20460. 

II. Background Information for this Final Rule

A. What is the NSPS Program?

Under section 111 of the CAA, "Standards of Performance for New Stationary 

Sources," the EPA lists categories of sources that, in the EPA’s judgment, cause or 

contribute significantly to air pollution, which may reasonably be anticipated to endanger 

public health or welfare pursuant to section 111(b)(1)(A). Section 111(b)(1)(B) requires 

the EPA to promulgate federal standards of performance for new sources within those 

categories. At the time the EPA establishes standards for a source category, the EPA 

prepares an analysis of the potential costs and benefits associated with the NSPS, which 

also includes the benefits from reductions in pollutants for which the standards do not set 

limits. For example, emission reductions associated with the requirements of this final 

rule will generate health benefits by reducing emissions of PM2.5, other criteria pollutants, 

such as CO, and non-criteria HAP. In addition, section 111(h) authorizes the EPA to 

promulgate design, equipment, work practice, operational, or combinations of standards 

to reflect the best systems of continuous emission reduction. The NSPS established under 
Page 13 of 326

section 111(b)(1)(B) do not establish standards of performance for existing sources. 

However, numerous states have acted independently of this rule to address new and 

existing sources as part of state implementation plan (SIP) measures necessary to ensure 

attainment and maintenance of the NAAQS. 

The level of control prescribed by section 111 of the CAA is BSER. In analyzing 

BSER, the EPA uses available information and considers the emissions reductions and 

incremental costs for different systems available at reasonable cost. The residential wood 

heaters source category is different from most NSPS source categories in that it is for 

mass-produced residential consumer products. Thus, important elements in determining 

BSER include the significant costs and environmental impacts of delaying production 

while models with those systems are designed, tested, field evaluated and certified. 

Section 111(b)(1)(B) of the CAA requires that the standards be effective upon the 

effective date of the NSPS. As noted earlier and discussed more fully later in this 

preamble, the stepped (phased) approach for residential wood stoves/heaters, hydronic 

heaters and forced-air furnaces that the EPA is promulgating considers these factors. That 

is, for this rulemaking, the EPA has determined the appropriate emission limits and 

compliance deadlines that together are representative of BSER. 

Section 111(b)(1)(B) of the CAA requires the EPA to periodically (every 8 years) 

review an NSPS unless it determines “that such review is not appropriate in light of 

readily available information on the efficacy of such standard.” In making revisions to an 

NSPS, the EPA will revise the standards of performance to reflect improvements in 

methods for reducing emissions, including consideration of what emissions limitation is 

achieved in practice. Numerous stakeholders have stated that the current body of 
Page 14 of 326

evidence strongly justifies the revision of the current residential wood heaters NSPS to 

capture the improvements in performance of such units since 1988 and to expand the 

applicability of this NSPS to include additional residential wood-burning heating devices 

that are available today. Some stakeholders have suggested that the EPA also develop 

additional NSPS to regulate residential heating devices that burn fuels other than or in 

addition to wood, e.g., coal, corn or grass. This final rule does not include any new 

federal requirements for heaters that solely burn fuels other than wood. However, the 

EPA may consider the need for such requirements during the next review.

B. Why is Residential Wood Smoke a Concern?

There is widespread recognition of the health impacts of particle pollution, to 

which wood smoke is a contributing factor in many areas. Wood smoke contains a 

mixture of fine particles and toxic air pollutants (e.g., benzene and formaldehyde) that 

can cause burning eyes, runny nose, and bronchitis. Exposure to fine particles has been 

associated with a range of health effects, including aggravation of heart or respiratory 

problems, changes in lung function and increased respiratory symptoms, as well as 

premature death. Populations that are at greater risk for experiencing health effects

related to fine particle exposures include older adults, children and individuals with preexisting heart or lung disease. Each year smoke from wood heaters contributes hundreds 

of thousands of tons of fine particles throughout the country—mostly during the winter 

months. Nationally, residential wood combustion accounts for 44 percent of total 

stationary and mobile polycyclic organic matter (POM) emissions, which accounts for 

nearly 25 percent of all area source air toxics cancer risks and 15 percent of noncancer 
Page 15 of 326

respiratory effects.3 Residential wood smoke causes many counties in the U.S. to either 

exceed the EPA’s health-based NAAQS for fine particles or places them on the cusp of 

exceeding those standards. For example, in places such as Keene, New Hampshire; 

Sacramento, California; Tacoma, Washington; and Fairbanks, Alaska; wood combustion 

can contribute over 50 percent of daily wintertime fine particle emissions.4 The concerns 

are heightened because wood stoves, hydronic heaters, and other heaters are often used 

around the clock in many residential areas. To the degree that older, dirtier, less efficient 

wood heaters are replaced by newer heaters that meet or exceed the requirements of this 

rule, the emissions would be reduced, and thus exposure as well, and fewer health 

impacts should occur. The health and air quality concerns associated with particle 

pollution and the effects of wood smoke are discussed in detail in the original listing of 

residential wood heaters under section 111(b) in the February 18, 1987, Federal 

Register, the original subpart AAA proposal in the February 18, 1987, Federal Register, 

the original subpart AAA promulgation in the February 26, 1988, Federal Register, the 

February 3, 2014 proposal of revisions to subpart AAA and the addition of subpart 

QQQQ and numerous other documents in the docket.

As discussed in the preamble to the February 3, 2014, proposed rule, and, in the 

Executive Summary (section I.A) of this preamble, particulate pollution from wood 

heaters is a significant national air pollution problem and human health issue. To the 

 

3

Strategies for Reducing Residential Wood Smoke. EPA-456/B-13-001, March 2013. 

Prepared by Outreach and Information Division, Air Quality Planning Division, Office of 

Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research 

Triangle Park, NC 27711. pp. 4-5.

4 Air Quality and Emissions Data; Supporting Information for the Residential Wood 

Heater New Source Performance Standard, August 14, 2013.
Page 16 of 326

degree that older, higher emitting, less efficient wood heaters are replaced by newer 

heaters that meet the requirements of this rule, setting these requirements for cleaner new 

stoves will result in substantial reductions in exposure and reduced health impacts. 

III. Summary of the Final Rule 

A. General

In response to the results of the review of the 1988 NSPS and in response to 

comments on the proposed rule and the NODA, the EPA is amending 40 CFR part 60, 

subpart AAA, Standards of Performance for New Residential Wood Heaters, and adding 

a new subpart QQQQ, Standards of Performance for New Hydronic Heaters and ForcedAir Furnaces. Subpart AAA applies to room heaters. This final rule broadens the 

applicability of wood heaters subject to the 1988 NSPS beyond adjustable burn rate wood 

heaters (the focus of the 1988 regulation) to specifically include all single burn rate wood 

heaters/stoves/appliances and pellet heaters/stoves/appliances and all other residential 

wood heaters except those specifically exempt in the rule, e.g., hydronic heaters and 

forced air furnaces regulated by subpart QQQQ. (Some pellet heaters/stoves/appliances

were not affected by the 1988 regulation.) This preamble uses the following terms 

interchangeably for appliances subject to subpart AAA: wood heaters, stoves and 

heaters/stoves/appliances. Subpart QQQQ applies to two specific types of wood heaters: 

hydronic heaters and forced-air furnaces plus any other wood-burning affected appliance

that meets the definition of central heater. This preamble uses the terms forced-air 

furnaces and warm-air furnaces interchangeably for such heaters/furnaces/appliances

affected by subpart QQQQ. Wood heaters, hydronic heaters and forced-air furnaces 
Page 17 of 326

manufactured after the effective date of this final rule will be required to meet PM 

emission limits.

This final rule does not include any federal emission limitations that would apply 

to heaters fueled solely by gas, oil or coal. In addition, this final rule does not include any 

new federal requirements associated with wood heaters or other wood-burning appliances 

that are already in use in people’s homes. The EPA continues to encourage state, local, 

tribal, manufacturer, retailer and consumer efforts to change out (replace) older heaters 

with newer, cleaner, more efficient heaters. Also, we continue to encourage state, local, 

and tribal authorities to develop site-specific installation and operating requirements and 

oversight to help ensure healthy air for all.

For this final action, the effective date is [INSERT DATE 60 DAYS AFTER

DATE OF PUBLICATION IN THE FEDERAL REGISTER] to allow for 

Congressional Review under the Congressional Review Act (CRA). Under the CRA, 5 

U.S.C. 801(a)(3), the effective dates of all “major” rules are delayed for 60 calendar days

after they are submitted to Congress or after they are published in the Federal Register, 

whichever date is later. This final action is a “major” rule within the meaning of the 

CRA.

Section IV summarizes the changes to the proposed rule reflected in the final rule,

and section V provides a summary of the major comments received and our responses. 

1. Certification Testing and Compliance

As with the 1988 NSPS, because of concern regarding potential negative impacts 

on small businesses and potential certification delays, this revised subpart AAA for wood 

heaters/stoves and new subpart QQQQ for hydronic heaters and forced-air furnaces 
Page 18 of 326

require manufacturers to participate in a certification program that tests a representative 

heater per model line rather than testing every heater. If the representative heater meets 

the applicable emission limits contained in this rule, the entire model line may be 

certified. Individual heaters within the model line are still subject to all other 

requirements, including labeling and operational requirements. Manufacturers are 

required to have quality assurance programs to ensure that all heaters within the model 

line conform to the certified design and meet the applicable emission limits. The EPA 

will continue to have the authority to conduct audits to ensure compliance. 

Additional requirements apply to entities other than the manufacturer. 

Wholesalers and retailers are also subject to the limits on sales of non-certified affected 

heaters. Wood heater test laboratories and certifying entities are subject to quality 

assurance and reporting requirements. This final rule for subpart AAA and subpart 

QQQQ requires the proper burn practices that have applied to the owner or operator of a 

wood heating appliance regulated under subpart AAA since 1988. In addition, new pellet 

heater/stove owners and operators will be required to use only the grades of pellet fuels 

and wood chips that are included in the owner’s manual based on the heater/stove 

certification tests. In this final rule, we are revising the original 1988 enforcement and 

audit provisions to reflect changes in industry practices and development of new tools 

and procedures. We are also taking final action to improve the previous test methods as 

well as adding new test methods. More details are in sections IV.D and V.

2. Stepped Compliance Approach

The 1988 NSPS addressed some of the specific characteristics of this source 

category by developing a stepped compliance approach that provided manufacturers a 
Page 19 of 326

two-phased implementation of emission limits. Considering that over 90 percent of the 

manufacturers and retailers are small businesses, we have included this approach in the 

revised subpart AAA and new subpart QQQQ in order to allow manufacturers lead time 

to develop, test, field evaluate and certify current technologies across their consumer 

product lines to meet Step 2 emission limits and in most cases to allow retailers to sellthrough inventory. Upon the effective date of this final rule, all new residential wood 

heaters subject to subparts AAA and QQQQ will be required to meet the NSPS standards. 

The standards are phased from immediate requirements on the effective date to Step 2 

emission limits five years later. The specific emission limits and dates for subparts AAA 

and QQQQ are shown in Table 3 and Table 4, respectively. To further ease the transition 

on small businesses, the EPA will not require new testing of heaters that have current 

certificates of compliance under the 1988 NSPS that show they meet the Step 1 emission 

levels. Those certificates are automatically extended beyond their current expiration date 

until the compliance deadline for the Step 2 emission limits. Also, this final rule 

automatically deems certified hydronic heaters that have been qualified at the Step 1 

emission level (or better) under the EPA voluntary partnership program for hydronic 

heaters or forced-air furnaces that have been independently certified at the Step 1 

emission level (or better) or under Canadian Standards Association B415.1-10.

3. NSPS Labels

The final rule requires that each room heater under subpart AAA and central 

heater under subpart QQQQ be equipped with a permanent label meeting the applicable 

requirements in § 60.536 and § 60.5478, respectively. The permanent label must include 

identifying information for the unit and its compliance certification status. The permanent 
Page 20 of 326

label must be installed so that it is readily visible both before and after the unit is 

installed. This requirement is needed to assist state, local and tribal officials in 

determining if a unit complies with state, local and tribal rules and in determining 

eligibility for any future change out (replacement) programs. Note that “readily visible” 

does not mean under the body of freestanding stove but it does allow an easily removable 

decorative façade to cover the label.

In the 1988 NSPS, temporary labels (e.g., hangtags) were required for wood 

heaters that are subject to the standards, as well as ones that are not (e.g., coal 

heaters/stoves). These temporary labels were intended to assist consumers in comparing

different appliance models and to inform the consumer about the importance of proper 

operation and maintenance. We proposed to remove the requirement for temporary 

labels, and we requested comment. After reviewing the comments received, the EPA now 

concludes that these temporary labels are most valuable if they assist purchasers in 

identifying the cleanest and most efficient heaters. Therefore, in this final rule the EPA is 

allowing (voluntary) a temporary NSPS label (hangtag) for each adjustable burn rate 

heater, single-burn rate heater, pellet heater/stove, hydronic heater and forced-air furnace

sold at retail that meets the Step 2 emission limits before the Step 2 compliance date. This 

temporary label option will end upon the Step 2 compliance date. 

In addition, we are providing an alternative compliance option for manufacturers 

who choose to demonstrate compliance with Step 2 emission limits using cord wood 

testing rather than the standardized crib wood testing, currently used for the primary 

compliance option for appliances regulated under subpart AAA and for hydronic heaters 

under subpart QQQQ. As discussed in the preamble to the February 3, 2014, proposed 
Page 21 of 326

rule, crib wood is a specified configuration and quality of dimensional lumber and 

spacers that improves the repeatability of the test method. Cord wood is a different 

specified configuration and quality of wood that more closely resembles what a typical 

homeowner would use. Cord wood testing is a better measure of how the heaters will 

perform on the type of fuel commonly used in homes. 

Each of these models would be equipped with both a permanent label and the 

voluntary option of a special temporary label (hangtag) informing consumers that these 

wood heaters were tested and certified when burning cord wood. The specific emission 

limits are discussed in sections III.B and III.C.

4. New Residential Masonry Heaters (Proposed Subpart RRRR)

The EPA is not taking final action at this time on proposed subpart RRRR for new 

residential masonry heaters. Our reason for taking no action at this time is to allow 

additional time for the Masonry Heater Association (MHA) to finish their efforts to 

develop revised test methods, an emissions calculation program and an alternative 

dimensioning standard. The MHA believes these efforts are critical because most 

masonry heaters are custom built on-site and testing each custom model would be 

difficult. The nationwide emission impacts of delaying regulating subpart RRRR are 

small relative to the impacts of regulating subparts AAA and QQQQ. Fewer than 

approximately 1,000 masonry heaters are manufactured each year and a total of less than 

10 tons per year of PM2.5 are currently emitted. In comparison, new wood burning 
Page 22 of 326

appliances covered by subparts AAA and QQQQ are estimated to number more than 

200,000 (2015) and currently emit more than 11,000 tons per year of PM2.5.

5

B. Room Heaters (revised subpart AAA)

1. Applicability

After the effective date, new heaters will be required to meet the updated 

standards. The new standards apply not only to adjustable burn rate wood heaters (the 

focus of the original regulation), but also to single burn rate wood heaters/stoves, pellet 

heaters/stoves, and any other affected appliance as defined in revised subpart AAA as a 

“room heater.” Subpart AAA, as amended, does not apply to new residential hydronic 

heaters or new residential forced-air furnaces because they are subject to their own 

subpart. The revised subpart AAA does not apply to fireplaces as defined in Subpart 

AAA. This final rule tightens the definition for “cook stoves” and adds definitions for 

“camp stoves” and “traditional Native American bake ovens” to clarify that they are not 

subject to the standard other than appropriate labeling for cook stoves and camp stoves

and no requirements for traditional Native American bake ovens. Finally, the revised 

subpart AAA clarifies that the emission limits apply only to wood-burning devices (i.e., 

not to devices that only burn fuels other than wood, e.g., gas, oil or coal).

2. Automatic EPA Certification for Currently Certified Heaters/Stoves that Meet the 

Step 1 Emission Levels 

In this final rule we make clear that those heaters/stoves with EPA certifications 

under the 1988 NSPS that show compliance with the Step 1 emission levels will be 

automatically deemed as certified to meet the Step 1 emission limits under this final rule 

 

5 Memo to USEPA from EC/R, Inc. Estimated Emissions from Wood Heaters. January 

2015.
Page 23 of 326

until the Step 2 compliance date. No separate certification will be required. Over 85 

percent of heaters/stoves being sold today already meet the Step 1 emission limit. This 

automatic certification will avoid unnecessary economic impacts on those manufacturers 

(over 90 percent are small businesses) who can then focus their efforts on developing a 

full range of cleaner models that meet Step 2 emission levels. This measure should also 

help avoid potential delays at laboratories conducting certification testing for heaters 

newly subject to the NSPS. 

3. Two-Step Compliance Approach

We are promulgating a two-step compliance approach that will apply to all new 

adjustable burn rate wood heaters, single burn rate wood heaters and pellet heaters/stoves. 

Under this approach, Step 1 emission limits for these sources will apply to each source 

manufactured on or after the effective date of the final rule or sold at retail on or after 

December 31, 2015. The approximately 8-month additional time for the retail sale 

requirement will allow retailers to sell their inventories of heaters that do not comply with 

the Step 1 emission limits. Step 2 emission limits for these sources will apply to each 

heater manufactured or sold at retail on or after the date 5 years after the effective date of 

the final rule. We are not including the alternative three-step emission limit compliance 

approach for which we also requested comment in the proposal. The comments 

overwhelmingly indicated that the three-step emission limit approach was inferior not 

only environmentally but also economically because it would, in effect, require many 

small manufacturers to engage in two rounds of research and development (R&D) rather 

than one in order to obtain the same eventual endpoint. 
Page 24 of 326

Table 3 summarizes the PM emissions limits that apply to each wood heater under 

this two-step approach. Note that the emissions standards are “as measured” by the test 

methods specified in the rule and are labeled as PM although the PM is essentially all

PM2.5. This avoids the potential extra testing costs of measuring PM2.5 specifically.

Table 3. Subpart AAA PM Emissions Limits

Phases/Steps PM

Emissions Limit

Step 1: upon the 

effective date of final 

rule

Step 2: 5 years after 

the effective date of 

the final rule

Step 2: cord wood 

alternative compliance 

option

4.5 g/hr 

2.0 g/hr

2.5 g/hr

We are allowing an alternative compliance option for manufacturers who choose 

to certify using cord wood (rather than crib wood) to meet the Step 2 limits. (As 

discussed earlier in this preamble, crib wood is a specified configuration and quality of 

dimensional lumber and spacers that improves the repeatability of the test method. Cord 

wood is a different specified configuration and quality of wood that more closely 

resembles what a typical homeowner would use.) Special permanent and temporary 

labels for room heaters certified with cord wood would specify that they meet a PM 

emissions limit of 2.5 g/hr. The bases for the crib wood primary emission limit of 2.0 g/hr 

and the cord wood alternative compliance option emission level of 2.5 g/hr for wood 

stoves, as well as the limited environmental impact of the differences in these levels, are 
Page 25 of 326

discussed in section V.A BSER and Particulate Emission Limits for Room Heaters

(revised subpart AAA).

The proposal would have required cord wood testing for all Step 2 compliance 

certifications. Cord wood testing is a better measure of how stoves actually perform in 

home use; however, we are concerned that many manufacturers (over 90 percent are 

small businesses) do not yet have experience with designing their stoves to perform well 

with cord wood testing. Some manufacturers may not be ready for cord wood testing by

the Step 2 compliance date and that would result in unreasonable economic impacts. 

Allowing the cord wood alternative compliance option acknowledges the efforts of the 

industry leaders and encourages others to follow their example. 

The revised subpart AAA does not include a compliance extension for small 

volume manufacturers. An extension for manufacture of adjustable burn rate heaters is 

not necessary because over 85 percent of these appliances already comply with Step 1 

emission levels. 

We are making a single determination of BSER for catalytic, noncatalytic and 

hybrid heater systems so as not to restrict open market competition. As in the 1988 

NSPS, we are requiring manufacturers to provide warranties on the catalysts, prohibit the 

operation of catalytic heaters/stoves without a catalyst and require operation according to 

the owner’s manual. In addition, we are requiring manufacturers to provide warranties for 

noncatalytic and hybrid heaters/stoves and require operation according to the owner’s 

manual. 

As discussed at proposal, we considered requiring efficiency standards (heat 

output divided by fuel input) to ensure that stoves are efficient and burn no more wood 
Page 26 of 326

than necessary for the heat demand so that the consumers can save money on fuel and so 

that the emissions are lower. We did not propose an efficiency standard because we did 

not have sufficient data, but the final rule uses our authority under section 114 to require

the manufacturer to submit third-party efficiency test data, submit the test data report to 

the EPA and post the results on the manufacturer’s web site. Also, we will include this 

submitted information on the EPA web site. This will help consumers to make informed 

choices to reduce fuel costs and emissions now and provide data for us to consider for 

future rulemaking. 

4. Emission Testing, Reporting and Certification

We are requiring emission testing, reporting and certification based on crib wood 

to demonstrate compliance with Step 1 and Step 2 emissions limits. As discussed in the 

preamble to the February 3, 2014, proposed rule, “crib wood” is a specified configuration 

and quality of dimensional lumber and spacers that improves the repeatability of the test 

method. In this final rule, we are also establishing an alternative compliance option that 

allows manufacturers to use cord wood for the certification tests. “Cord wood” is a 

different specified configuration and quality of wood that more closely resembles what a 

typical homeowner would use.

Commenters overwhelmingly agreed that tuning heaters for crib wood

certification tests often results in poorer performance in homes. Based on the existence of 

a viable draft cord wood test method and the expectation at proposal that the ASTM 

International (formerly known as American Society of Testing and Materials) test

methods for cord wood would be complete soon after the NSPS proposal and that 

significant testing of wood heaters re-tuned to perform well on cord wood would occur 
Page 27 of 326

before promulgation of this final rule, the EPA proposed to require testing only with cord 

wood for compliance with Step 2 emissions limits. We still encourage manufacturers to 

design wood heaters that best represent in-home performance on cord wood that 

consumers use as soon as possible. However, the ASTM cord wood test methods have 

not been completed and only limited testing using the draft methods has occurred.

We received numerous comments from noncatalytic stove manufacturers and 

laboratories and some states with concerns about when the cord wood test methods would 

be ready and how quickly noncatalytic stoves could be redesigned to perform well with 

cord wood certification testing that we proposed for Step 2, i.e., 5 years after the effective 

date. As discussed in the NODA, as of May 2014, we had test data for three catalytic or 

hybrid wood heaters/stoves that performed very well on cord wood. However, 

considering all of the above, we have determined that we do not have sufficient data at 

this time to support a regulatory requirement for cord wood testing.

We expect that many manufacturers will choose the alternative cord wood 

compliance testing option so that consumers will have more opportunities to purchase 

stoves that are tuned for in-home use. We will consider alternative cord wood test method 

requests on a case-by-case basis until we are convinced that improved test methods have 

been sufficiently demonstrated that they can be relied upon for regulatory purposes. For 

now, we will be receptive to alternative test method requests that use the current ASTM 

draft method. Also, we will be receptive to other requests that are sufficiently 

demonstrated, ideally using the EPA Method 301 validation procedures. Additionally, we 

expect that within the next few years we will receive enough cord wood test data for the 

EPA to establish revised certification requirements based on cord wood testing. 
Page 28 of 326

The final rule requires that pellets for the certification tests be only those that have 

been graded under a licensing agreement with a third-party organization and meet the 

minimum quality specifications in § 60.532. Commenters indicated that several 

organizations are currently available and others are planned, for example, the Pellet Fuels 

Institute (PFI), ENplus and CANplus. Details of the PFI program are available at 

http://pelletheat.org/pfi-standards/pfi-standards-program/. Details of the ENplus program 

are at http://www.enplus-pellets.eu/wp-content/uploads/2012/01/ENplus-Handbook2.0.pdf. Details of the CANplus program are at 

http://controlunion.ca/fileupload/CA/Certifications/ENplusCANplus/CANplus_handbook

_v2-0.pdf. Manufacturers’ data show that pellet fuel quality assurance is necessary to 

ensure that the appliances operate properly and meet the certified emission limits. 

At this time, we lack sufficient data to issue a CO emissions limit in today’s final 

rule. However, this final rule uses our authority under section 114 to require

manufacturers to determine CO emissions during the compliance tests (as is typically 

done already), report those results to the EPA and include those results on the 

manufacturer’s web site, so that data will be available to consumers, and to the EPA and 

states for CO NAAQS compliance implementation plan considerations and future wood 

heater rulemakings. We intend to include context and consumer-friendly summaries of 

the submitted CO emissions data on the EPA Burn Wise web site also.

Like the 1988 subpart AAA, this final rule uses the EPA authority under section 

114 of the CAA to require each manufacturer to submit applications for certifications of 

compliance for all new models. We are revising the certification process to include thirdparty certifiers in order to reduce the potential for certification delays that could result 
Page 29 of 326

from insufficient capacity. However, commenters expressed concern, which we share, 

that there may not be sufficient third-party certifier capacity and review and approval 

capacity by the EPA, especially in the first year. Therefore, to avoid unfairly restricting

the production and sales of manufacturers who do all the things they should do and then

potentially have to wait on EPA approval, we have added a conditional, temporary 

approval by the EPA based on the manufacturer’s submittal of a complete certification 

application. The application must include the full test report by an EPA-accredited 

laboratory and all required compliance statements by the manufacturer. The conditional 

approval would allow manufacture and sales for 1 year or until EPA review of the 

application, whichever is earlier. Within that year, the manufacturer must submit a 

certificate of conformity by a third-party certifier. (In this preamble, we use the terms 

“third-party certifier,” “certifying body,” “certifying entity” and “certifying body/entity” 

interchangeably.)

The EPA is revising the definition of “Accredited Test Laboratory,” from only 

EPA-accredited laboratories to include laboratories accredited by a nationally recognized 

accrediting body/entity to perform testing for each of the test methods specified in this 

NSPS under ISO-IEC6 Standard 17025. Laboratories must be approved by the EPA 

before beginning certification testing. Current EPA-accredited laboratories may retain 

their accreditation until 3 years after the effective date of this final rule. Laboratories that 

are not currently EPA-accredited must achieve ISO-accreditation and register with the 

EPA within 6 months of the effective date of this rule. Laboratories must report any 

 

6 The International Organization for Standardization (ISO) and the International 

Electrotechnical Commission (IEC) prepare and publish international standards.
Page 30 of 326

changes in their accreditation and any deficiencies found under ISO 17025 to the EPA, 

and the EPA may revoke approval if warranted. 

The EPA is requiring a “Certifying-Body-Based Certification Process” beginning 

6 months after the effective date of this final rule for all heaters/stoves except hydronic 

heaters. For hydronic heaters, the “Certifying-Body-Based Certification Process” is 

required upon the effective date of this final rule because this certification process has 

already been required under EPA’s Hydronic Heater Partnership Program since October 

2008. Under this process for all heaters/stoves subject to subparts AAA and QQQQ, after 

testing is complete, a certification of conformity with the PM emissions limits must be 

issued by a certifying body with whom the manufacturer has entered into contract for 

certification services. The certifying body must be accredited under ISO-IEC Standard 

17065 and register their credentials with the EPA and receive EPA approval prior to 

conducting any certifications or related work used as a basis for compliance with this rule 

and report any changes in their accreditation and any deficiencies found under ISO 

17065. Any certifying body that is approved by the EPA and is ISO-accredited is 

required to act in such a way that will not create a conflict of interest and work with 

integrity and honesty. The EPA will oversee the certifying body’s work and retain the 

right to revoke the EPA approvals if appropriate. Upon review of the test report and 

quality control plan submitted by the manufacturer, the certifying body may certify initial 

compliance and submit the required documentation on behalf of the manufacturer to the 

EPA’s Office of Enforcement and Compliance Assurance for review, approval and listing 

of the certified appliance.
Page 31 of 326

The rule continues to require the owner or operator of a wood heating appliance to 

operate the heater consistent with the owner’s manual and not burn improper fuel. 

Owners and operators must operate pellet fuel appliances with the grades of pellet fuels 

that are included in the owner’s manual. Manufacturers are required to void their 

warranties in cases of improper operation. Numerous states expressed their support for 

the continuation of these requirements. Some states and local jurisdictions have enforced 

similar requirements, and this final rule will allow the EPA to approve state requests for

delegation of enforcement authority for these NSPS requirements. In addition, we expect 

many state, local and tribal authorities will adopt some of the important and very 

successful strategies in Strategies for Reducing Wood Smoke,

7

including changing out

(replacing) older heaters with newer, cleaner, more efficient heaters and developing sitespecific installation and operating requirements to ensure heaters are not over-sized, 

avoid nuisance conditions, and ensure proper operation, e.g., using EPA Method 22 

observations of visible emissions as an indicator of potential poor or improper operation

to help ensure healthy air for all.

The rule continues to contain the crucial quality assurance provisions in the 1988 

NSPS. For example, manufacturers must request EPA approval of model line recertifications or new certifications whenever any change is made in the original design 

that could potentially affect the emissions rate for that model line or when any of several 

specified tolerances of key components are changed. The 1988 requirements for 

manufacturer quality assurance programs are strengthened in the revised rule by requiring 

 

7

Strategies for Reducing Residential Wood Smoke. EPA-456/B-13-001, March 2013. 

Prepared by Outreach and Information Division, Air Quality Planning Division, Office of 

Air Quality Planning and Standards, U.S. Environmental Protection Agency, Research 

Triangle Park, NC 27711.
Page 32 of 326

the manufacturer within 6 months after the effective date to contract for a certifying-body 

to conduct quality assurance audits within 12 months. The certifying body will conduct 

regular, unannounced audits to ensure that the manufacturer’s quality control plan is 

implemented properly.

The EPA audit testing programs of the 1988 NSPS are retained under the revised 

rule, although they are streamlined and simplified to better ensure compliance and to 

clarify that audits can be based on any information the EPA has available and that audits 

do not need to be statistically random. Also, the rule clarifies that the EPA and states are 

allowed to be present during the audits and that states (and other entities, including the 

public) may provide the EPA with information that may ultimately be used in any EPA 

enforcement and compliance assurance efforts. 

C. Central Heaters: Hydronic Heaters and Forced-Air Furnaces (subpart QQQQ)

1. Applicability

After the effective date, new heaters will be required to meet the new standards. 

In this final rule, the EPA is adding 40 CFR part 60, subpart QQQQ, which applies to all 

new wood-fired residential hydronic heaters, wood-fired forced-air furnaces and any 

other wood-fired affected appliance defined in subpart QQQQ as a “central heater.” 

Wood-fired means designed or marketed to be capable of burning wood or used to burn 

wood. For example, a coal-fired heater cannot be marketed as capable of wood-burning 

unless it meet the requirements of this rulemaking and the marketing brochures and 

owner’s manuals must be clearly specific to coal rather than wood. Hydronic heater 

means a fuel-burning device designed to burn wood or wood pellet fuel for the purpose of 

heating building space and/or water through the distribution, typically through pipes, of a 
Page 33 of 326

fluid heated in the device, typically water or a water and antifreeze mixture. Forced-air 

furnace means a fuel burning device designed to burn wood or wood pellet fuel that 

warms spaces other than the space where the furnace is located, by the distribution of air 

heated by the furnace through ducts.

This new “central heater” categorization better ensures that all appliances affected 

under this new subpart are included in this final action. Adding subpart QQQQ addresses 

heater appliance types in the 1987 residential wood heater source category listing that 

were not regulated by the 1988 NSPS. This new subpart is designed similar to subpart 

AAA, i.e., certification testing of a representative unit in a model line, label requirements, 

associated quality assurance requirements and stepped (phased) implementation.

The provisions of subpart QQQQ apply to each affected unit that is manufactured 

or sold at retail on or after [INSERT DATE 60 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER].

2. Automatic EPA Certification for Currently Certified or Qualified Central Heaters that 

Meet the Step 1 Emission Levels 

In this final rule we make clear that those hydronic heaters with valid EPA Phase 

2 qualifications under the voluntary EPA Hydronic Heater Partnership Agreement of 

October 12, 2011, or hydronic heaters certified by the New York State Department of 

Environmental Conservation (NYSDEC) that show compliance with the Step 1 emission 

limits will be automatically deemed EPA certified to meet the Step 1 emission limits 

under this final rule until the Step 2 compliance date. Also, residential pellet hydronic 

heaters/boilers that have been qualified under the Renewable Heat New York (RHNY) 

program will be automatically deemed EPA certified to meet Step 1. (Note that the 

RHNY program requires pellet heating systems to include installation of thermal storage 
Page 34 of 326

to maintain high-efficiency and low emissions performance throughout daily and annual 

cycles. The minimum size thermal storage for boilers less than 85,000 BTU/hr is 119 

gallons or 2.0 gallons per 1,000 BTU/hr, whichever is less. For boilers greater than 

85,000 BTU/hr, the minimum heat storage is 2.0 gallons per 1,000 BTU /hr.) No separate 

EPA certification will be required. Similarly, forced-air furnaces independently certified 

(i.e., not self-tested) under Canadian Standards Association (CSA) B415.1-10 as well as 

forced-air furnaces certified by the NYSDEC that show compliance with the Step 1 

emission limits will be deemed EPA certified to meet the Step 1 emission limits under 

this final rule until the Step 2 compliance date. This automatic EPA certification will 

avoid unnecessary economic impacts on those manufacturers (over 90 percent are small 

businesses) who can then focus their efforts on developing a full range of cleaner models 

that meet Step 2 emission levels. This measure should also help avoid potential delays at 

laboratories conducting certification testing for heaters newly subject to the NSPS. 

3. Stepped Compliance Approach

We are promulgating a stepped compliance approach that will apply to all new 

central heaters.

For hydronic heaters, standards will apply to each hydronic heater manufactured 

after [INSERT DATE 60 DAYS AFTER DATE OF PUBLICATION IN THE 

FEDERAL REGISTER] and each hydronic heater sold after December 31, 2015. Step 1 

PM emission limits will apply to each hydronic heaters manufactured on or after 

[INSERT DATE 60 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER] or sold at retail after December 31, 2015. Step 2 PM emission limits will 

apply to each hydronic heater manufactured or sold at retail on or after [INSERT DATE 
Page 35 of 326

60 DAYS PLUS 5 YEARS AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER].

For hydronic heaters, we are not promulgating the alternative three-step emission 

limit approach for which we requested comment in the proposal. The comments 

overwhelmingly indicated that the three-step emission limit approach was inferior not 

only environmentally but also economically because it would, in effect, require many 

small manufacturers to engage in two rounds of R&D rather than one in order to obtain 

the same eventual endpoint.

For forced-air furnaces, standards will apply to each forced-air furnace 

manufactured or sold after [INSERT DATE 60 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]. Work practice and operational 

standards will apply to each forced-air furnace manufactured or sold at retail after 

[INSERT DATE 60 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER]. Step 1 PM emission limits will apply to small (less than 65,000 BTU/hr 

heat output) forced-air furnaces manufactured or sold on or after [INSERT DATE 1 

YEAR PLUS 60 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER]. Step 1 PM emission limits will apply to large (65,000 BTU/hr heat output 

or larger) forced-air furnaces manufactured or sold on or after [INSERT DATE 2 

YEARS PLUS 60 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER]. Step 2 PM emission limits will apply to each forced-air furnace 

manufactured or sold at retail on or after [INSERT DATE 60 DAYS PLUS 5 YEARS 

AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].
Page 36 of 326

For forced-air furnaces, we are not promulgating the alternative three-step 

emission limit approach for which we requested comment in the proposal. The comments 

overwhelmingly indicated that the three-step emission limit approach was inferior not 

only environmentally but also economically because it would, in effect, require many 

small manufacturers to engage in two rounds of R&D rather than one in order to obtain 

the same eventual endpoint. However, commenters were very concerned about the 

infeasibility of enforcing an emission limits for forced-air furnaces due to the technical 

and economic impracticability of testing and certifying approximately 50 forced-air 

furnaces in the 60 days between publication of this rule and the effective date. For 

example, a typical forced-air furnace certification test takes approximately 1 week in the 

laboratory after the furnace is shipped to the laboratory and a time is scheduled to begin 

testing. Typically, the laboratory takes approximately 3 or 4 weeks to prepare a complete 

test report for the manufacturer to submit to the EPA. A reasonable overall estimate is 

approximately 1.25 months, not counting potential conflicts with other testing in the 

laboratories. Currently, there are only 4 laboratories that can test forced-air furnaces. We 

estimate that approximately 12 small forced-air furnaces and 38 large forced-air furnaces 

would need to be tested as soon as possible. If those tests were to be divided equally 

among the 4 laboratories, it would take a minimum of approximately 4 months to submit 

the 12 certification test reports for the small furnaces and an additional year to submit the 

38 certification test reports for the large furnaces to the EPA, far longer than the 60 days 

between the publication date and the effective date. Thus, as noted above, we are 

requiring work practice and operational standards on the effective date as allowed under 

section 111(h)(2) B) of the CAA, and requiring Step 1 PM emission limits for small 
Page 37 of 326

forced-air furnaces 1 year after the effective date and Step 1 PM emission limits for large 

forced-air furnaces 2 years after the effective date. Specifically, the manufacturers must 

develop model-specific descriptions of proper operation and best practices; include them 

in their owner’s manuals; provide training on them to their distributors; and provide them 

in written and video format to purchasers/operators/users of their heaters. The specific 

details that must be included in owner’s manuals are in § 60.5474 and Appendix I of this 

rulemaking. 

The following are excerpts of the operational standards required in this rule that 

must be included in the owner’s manuals. Operators must not burn unseasoned wood. 

The use of properly split, stored and seasoned wood has much lower PM emission 

than high-moisture wood, i.e., green wood or wet wood. Operators must not burn 

improper fuels such as (1) residential or commercial garbage; (2) lawn clippings or yard 

waste; (3) materials containing rubber, including tires; (4) materials containing plastic;

(5) waste petroleum products, paints or paint thinners, or asphalt products; (6) materials 

containing asbestos; (7) construction or demolition debris; and (8) paper products; 

cardboard, plywood or particleboard (Note that best practices do allow the use of fire 

starters made from paper, cardboard, saw dust, wax and similar substances for the 

purpose of starting a fire in an affected heater); (9) railroad ties or pressure treated 

lumber; (10) manure or animal remains; (11) salt water driftwood or other or other 

previously salt water saturated materials; (12) unseasoned wood; and (13) any materials 

that are not included in the warranty and owner’s manual for the subject heater or 

furnace.
Page 38 of 326

The owner’s manual and training materials must also educate operators on the use 

of proper operating practices, including correct positioning of bypasses and air dampers 

during startup, normal operation and reloading. Proper practices also include checking air 

tubes, catalysts (if so equipped), heat exchangers and other critical parts of the heater to 

ensure they are working properly and are maintained as needed. Best burn operational 

practices are already highlighted in many manufacturers’ owner’s manuals, educational 

materials from HPBA and Burn Tips on EPA’s Burn Wise web site. Numerous comments 

noted that best work practices and proper operation and maintenance can significantly 

reduce emissions at reasonable costs. Thus, considering all of the above, the EPA has 

determined that these work practice and operational standards represent the best systems 

of emission reduction as required by section 111(h)(1) for the immediate time frame from 

the effective date until the Step 1 PM emissions limits apply. More discussion of 

comments on stepped compliance and the EPA’s responses are in section V. Summary of 

Major Comments and Responses.

Table 4 summarizes the PM emissions limits for hydronic heaters and forced-air 

furnaces that will apply at each step. Note that the emissions standards are “as measured” 

by the test methods specified in the rule and are labeled as PM although the PM is 

essentially all PM2.5. This avoids the potential extra testing costs of measuring PM2.5

specifically.

Table 4. Subpart QQQQ PM Emissions Limits

Appliance Steps Particulate Matter 

Emissions Limits
Page 39 of 326

Residential 

Hydronic 

Heater

Step 1: on or after 

[INSERT DATE 60 

DAYS AFTER DATE 

OF PUBLICATION IN 

FEDERAL REGISTER]

Step 2: on or after 

[INSERT DATE 60 

DAYS PLUS 5 YEARS 

AFTER DATE OF 

PUBLICATION IN 

FEDERAL REGISTER]

Step 2: cord wood 

alternative compliance 

option

0.32 lb/mmBtu heat 

output (weighted 

average) and a cap of 

18 g/hr for each 

individual test run

0.10 lb/mmBtu heat 

output for each 

individual burn rate

0.15 lb/mmBtu heat 

output for each 

individual burn rate
Page 40 of 326

We are allowing an alternative compliance option for manufacturers who choose 

to certify using cord wood (rather than crib wood) to meet the Step 2 limits for hydronic 

heaters. The proposal would have required cord wood testing for all Step 2 compliance 

certifications. Cord wood testing is a better measure of how stoves actually perform in 

Forced-Air 

Furnace

Work practice and 

operational standards: 

on or after [INSERT 

DATE 60 DAYS 

AFTER DATE OF 

PUBLICATION IN 

THE FEDERAL 

REGISTER]

Step 1 for small 

furnaces: on or after 

[INSERT DATE 60 

DAYS PLUS 1 YEAR 

AFTER DATE OF 

PUBLICATION IN 

FEDERAL REGISTER]

Step 1 for large 

furnaces: on or after 

[INSERT DATE 60 

DAYS PLUS 2 YEARS 

AFTER DATE OF 

PUBLICATION IN 

FEDERAL REGISTER]

Step 2 for small or large

furnaces: on or after 

[INSERT DATE 60 

DAYS PLUS 5 YEARS 

AFTER DATE OF 

PUBLICATION IN 

FEDERAL REGISTER]

(using cord wood as 

specified in CSA 

B415.1-10)

No specific PM limit

0.93 lb/mmBtu heat 

output (weighted 

average)

0.93 lb/mmBtu heat 

output (weighted 

average)

0.15 lb/mmBtu heat 

output for each 

individual burn rate
Page 41 of 326

home use; however, we are concerned that many manufacturers (over 90 percent are 

small businesses) do not yet have experience with designing their stoves to perform well 

with cord wood testing. Numerous hydronic heater manufacturers may not be ready by 

the Step 2 compliance date and that could result in unreasonable economic impacts. 

Allowing this option acknowledges the efforts of the industry leaders and encourages 

others to follow their example. Special (required) permanent and (voluntary) temporary 

labels for heaters certified with cord wood would specify that they meet a PM emissions 

limit of 0.15 lb/mmBtu heat output. The Step 2 PM emission limit for forced-air furnaces 

matches the hydronic heater alternate cord wood option emission level of 0.15 lb/mmBtu

because CSA B415.1-10 already specifies cord wood for the certification tests. The bases 

for the emission levels are discussed in section V.B BSER and Particulate Emission 

Limits for Central Heaters (subpart QQQQ).

We are making a single determination of BSER for catalytic, noncatalytic, hybrid, 

cord wood and pellet heaters and furnaces in order to not restrict open market 

competition. We are requiring manufacturers to provide warranties on the catalysts, 

prohibit the operation of catalytic heaters and furnaces without a catalyst and require 

operation according to the owner’s manual. In addition, we are requiring manufacturers 

to provide warranties for noncatalytic and hybrid heaters and furnaces and require 

operation according to the owner’s manual. 

As discussed at proposal, we considered requiring efficiency standards (heat 

output divided by fuel input) to ensure that heaters are efficient and burn no more wood 

than necessary for the heat demand so that the consumers can save money on fuel and so 

that the emissions are lower. We did not propose an efficiency standard because we 
Page 42 of 326

concluded we do not yet have sufficient data, but the final rule uses our section 114 

authority to require efficiency testing and reporting to the EPA. We will include context 

and summaries of this information on the EPA Burn Wise web site. This will help better 

inform consumers so they can choose the best-performing heaters now that will also save 

them money on fuel costs and also reduce PM emissions by burning less wood. This will 

also provide data to states and the EPA as we consider future wood heater rulemaking. 

At this time, we lack sufficient data to issue a CO emissions limit in today’s final 

rule. However, this rule uses our section 114 authority to require manufacturers to 

determine CO emissions during the compliance tests (as typically conducted), report 

those results to the EPA and include those results on the manufacturer’s web site. This 

will help better inform consumers so they can choose the best-performing heaters that

have less CO emissions and less health concerns for themselves and their neighbors. This 

will also provide data to states and the EPA as we consider future rulemaking. We intend 

to include context and summaries of the submitted CO emissions data on the EPA Burn 

Wise web site also.

In this final rule, we are not setting limits on visible emissions, and we are not 

prohibiting use in non-heating seasons. However, operators should note that some state, 

local and tribal jurisdictions have limits, prohibitions and other requirements that must be 

followed. 

Like the subpart AAA requirements, the subpart QQQQ requirements provide 

additional time for the sale of unsold hydronic heaters manufactured before the 

compliance date. This additional sell-through time does not include forced-air furnaces 

because EPA has determined that it is reasonable for forced-air furnace manufacturers to 
Page 43 of 326

revise their owner’s manuals, training and marketing materials to comply with the work 

practice and operational standards by the effective date. 

As in subpart AAA, subpart QQQQ includes a list of prohibited fuels because 

their use would cause poor combustion or even hazardous conditions. As in subpart 

AAA, subpart QQQQ requires that the owner or operator must operate the hydronic 

heater or forced-air furnace in a manner that is consistent with the owner’s manual and 

the rule requires the manufacturer to discuss the best operating practices in the owner’s 

manual. For pellet-fueled appliances, operation according to the owner’s manual includes 

operation only with pellet fuels that are specified in the owner’s manual. As in subpart 

AAA, manufacturers must only specify graded and licensed pellets that meet certain 

minimum requirements. Data show that pellet quality is important to ensure that the 

appliances operate properly such that emissions are within the appliance certification 

limits. 

The permanent labeling requirements and owner’s manual requirements in 

subpart QQQQ are similar to the guidelines in the EPA’s current voluntary hydronic 

heater program with some improvements. Like in subpart AAA, the temporary labels 

(hangtags) are voluntary and are only for models that meet Step 2 levels before the 

compliance date and these hangtags end upon the Step 2 compliance date. Subpart 

QQQQ also has a cord wood alternative compliance option with a special permanent 

label and a voluntary temporary label (hangtag) for models that meet Step 2 using cord 

wood. The structure of the rest of subpart QQQQ is similar to the subpart AAA 

certification and quality assurance process.

4. Emission Testing, Reporting and Certification
Page 44 of 326

The final rule requires that before manufacture and sale at retail, all affected 

hydronic heaters and forced-air furnaces subject to subpart QQQQ must conduct 

certification compliance testing, submit a certificate of compliance and receive EPA 

approval for the Step 1 and Step 2 PM emission limits by the dates shown in Table 4

For hydronic heaters, we are requiring emission testing, reporting and certification 

based on crib wood to demonstrate compliance with Step 1 and Step 2 emissions limits. 

The final rule requires crib wood emission testing of hydronic heaters by one of the 

following methods: EPA Method 28 WHH in its entirety or EPA Method 28 WHH-PTS 

(with approved adjustment for crib wood versus cord wood) or ASTM E2618-13 with 

conditions or European National (EN) test method EN 303-5 with conditions. We note 

that EPA’s current NSPS general provisions provide that affected sources may request 

EPA approval of alternative test methods on a case-by-case basis as appropriate. See 40 

CFR 60.8(b). 

Commenters overwhelmingly agreed that tuning heaters for crib wood 

certification tests often results in poorer performance in homes. Based on the existence of 

viable draft cord wood test methods and the expectation that the ASTM test methods 

would be final soon after the NSPS proposal and that significant testing of heaters retuned to perform well on cord wood would occur before promulgation of this final rule, 

the EPA proposed to require testing with cord wood for the Step 2 emissions limits. We 

still encourage manufacturers to design wood heaters that best represent in-home

performance on cord wood that consumers use as soon as possible. However, the ASTM 

cord wood test methods have not been completed and only limited testing using the draft 

methods has occurred.
Page 45 of 326

We received numerous comments with concerns about when the cord wood test 

methods would be ready and how quickly heaters could be redesigned to perform well 

with cord wood certification testing that we proposed for Step 2, i.e., 5 years after the 

effective date. At proposal, we had limited test data for heaters using cord wood. 

Considering all of the above, we have determined that we do not have sufficient data at 

this time to adequately support a regulatory requirement for cord wood testing.

We expect that many manufacturers will choose the alternative cord wood 

compliance testing option so that consumers will have more opportunities to purchase 

stoves that are tuned for in-home use. We will consider alternative cord wood test method 

requests on a case-by-case basis until we are convinced that improved test methods have 

been sufficiently demonstrated that they can be relied upon for regulatory purposes. For 

now, we will be receptive to alternative test methods requests that use the current ASTM 

draft methods. We will also be receptive to other alternative test method requests that are 

adequately demonstrated, ideally according to the EPA Method 301 validation 

procedures. Additionally, we expect that within the next few years we will receive 

enough cord wood test data for the EPA to establish revised certification requirements 

based on cord wood testing. 

In this final rule, the EPA is relying on the cord wood test method that has been 

developed by the CSA for forced-air furnaces. The current version of CSA B415.1-10 

was published in March 2010, and it includes not only the forced-air furnace test method 

but also Canadian emission performance specifications for indoor and outdoor central 

heating appliances.
Page 46 of 326

In this final rule, we are relying on efficiency test methods that have been 

developed by the CSA. The current version of CSA B415.1-10 was published in March 

2010.

As discussed earlier in section III.B.4 of this preamble, regarding the certification 

process for room heaters (revised subpart AAA), we are also requiring third-party 

certifiers for hydronic heaters and forced-air furnaces so as to reduce the potential for 

certification delays that could result from errors in testing. However, for forced-air 

furnaces, we are concerned that there may not be sufficient third-party certifier capacity 

specific to forced-air furnace testing according to the CSA B415.1-10 test method and 

review and approval capacity by the EPA, especially in the first year. We do not want to 

unfairly restrict the production and sales of forced-air furnace manufacturers who do all 

the things they should do and then potentially have to wait on EPA approval. Thus, we 

have added a conditional, temporary approval by the EPA for forced-air furnaces based 

on the manufacturer’s submittal of a complete certification application. The application 

must include the full test report by an EPA-approved laboratory and all required 

compliance statements by the manufacturer. The conditional approval would allow 

forced-air furnace manufacture and sales for 1 year or until EPA review of the 

application, whichever is earlier. Within that year, the manufacturer must submit a 

certificate of conformity by a third-party certifier.

The 1-year conditional, temporary approval by the EPA does not apply to 

hydronic heaters because they have been required to submit third-party certifications for 

the EPA hydronic heater voluntary partnership program since 2008 and will continue to 

do so under this NSPS.
Page 47 of 326

IV. Summary of Significant Changes Following Proposal

This section is a summary of the significant changes from the proposed rule based 

on the comments and additional material we received and have carefully considered. The 

reasons for these changes and their potential impacts are in the Response to Comments 

(RTC) document and are summarized in section V Summary of Major Comments and 

Responses. 

A. Best Systems of Emission Reduction/Particulate Emission Limits

We received considerable comment on the proposed PM emission limits that is 

relevant to our determination of BSER. As explained in more detail in section V, these 

final emission limits represent significant advances in stove technology and substantial 

reductions in emissions, both collectively and from individual units.

1. Room Heaters

The EPA is changing the proposed Step 2 PM emissions limit for new residential 

room heaters, including catalytic and noncatalytic adjustable rate wood heaters, single 

burn rate wood heaters and pellet heaters/stoves from 1.3 g/hr to 2.0 g/hr using crib 

wood. Compliance for room heaters will be determined using the weighted average of 

burn rates rather than requiring each individual burn rate to meet the limit. To reduce 

potential certification delays and unnecessary costs for small businesses, we are adding 

an automatic Step 1 EPA approval for models with valid EPA certifications under the 

1988 NSPS that show that the models achieve the Step 1 emission levels. Manufacturers 

may choose to test using either crib wood or cord wood. If the manufacturers choose the 

cord wood alternative compliance option, the PM emission limit for cord wood is 2.5 

g/hr. Although the number is higher, the cord wood test method is more reflective of fuel 
Page 48 of 326

that is used in homes and the data available to the EPA indicate that this PM emission 

level is at least as stringent as the 2.0 g/hr primary crib wood testing emission limit. More 

details on this are in section V.A Summary of Major Comments and Responses. 

For wood heater/stove certification tests using cord wood, the EPA is allowing 

(voluntary) manufacturers to use a special EPA label which recognizes that cord wood 

testing more closely reflects actual in-home use. 

2. Central Heaters: Hydronic Heaters and Forced-Air Furnaces

For new residential hydronic heaters, the final rule keeps the proposed Step 1 

weighted average PM emission rate of 0.32 lb/mmBTU heat output, establishes a Step 1 

PM emissions cap of 18 g/hr for any individual test run and adds automatic Step 1 EPA 

certification for hydronic heater models if they are already qualified as meeting the Phase 

2 emissions level of the EPA’s voluntary program. The change from the proposed Step 1 

cap of 7.5 g/hr to the final rule Step 1 cap of 18 g/hr was to match the Phase 2 emission 

levels of the EPA voluntary program and reduce potential certification delays. To further 

reduce potential certification delays and unnecessary costs for small businesses, we are 

also adding automatic Step 1 EPA certification for hydronic heater models certified by

NYSDEC that demonstrate the models achieve the Step 1 levels and RHNY-qualified 

pellet hydronic heaters. Similarly, we are adding automatic Step 1 EPA certification for 

new forced-air furnaces that are independently certified (i.e., not self-tested) under CSA 

B415.1-10 to meet the Step 1 emission level or that are certified by NYSDEC and meet 

the Step 1 emission level. For forced-air furnaces for Step 1, we deleted the 7.5 g/hr 

particulate emission limit per individual burn rate because the CSA B415.1-10 
Page 49 of 326

certifications are based on the weighted average, not the g/hr limit, and because the 

manufacturers do not have experience with meeting g/hr limits for these furnaces. 

For hydronic heaters, we are changing the proposed Step 2 PM emissions limit of 

0.06 lb/mmBtu heat output to 0.10 lb/mmBtu heat output for each individual burn rate, 

tested on crib wood. Manufacturers may choose to test using either crib wood or cord 

wood. If the manufacturer chooses the cord wood alternative compliance option, the Step 

2 PM emission limit for cord wood is 0.15 lb/mmBtu heat output. Although the number is 

higher, the cord wood test method is more reflective of the fuel that is used in homes and 

the limited cord wood data available to the EPA indicate that this PM emission level is at 

least as stringent as the 0.10 lb/mmBtu heat output crib wood testing emission limit. For 

forced-air furnaces, the Step 2 PM emission level matches the hydronic heater cord wood 

alternative option because forced-air furnaces are certified using CSA B415.1-10, which 

already specifies cord wood as the test fuel. Details on the bases of the emission levels 

are in section V, Summary of Responses to Major Comments.

For hydronic heaters and forced-air furnaces tested with cord wood, the EPA is 

allowing (voluntary) manufacturers to use special permanent labels and EPA temporary 

labels (hangtags) which recognize that cord wood testing more closely reflects actual 

operation under in-home-use conditions.

3. Masonry Heaters

As stated in section III of this preamble, the EPA is not taking final action on 

proposed subpart RRRR for new residential masonry heaters at this time. Comments 

indicated that the Masonry Heater Association (MHA) needs more time to finish their 

efforts to develop revised test methods, alternative compliance calculation procedures 
Page 50 of 326

and dimensioning procedures. The MHA comments stated that the cost of testing 

masonry heaters is high and impractical because almost all are custom-built onsite. After 

we receive additional information from MHA and others, we will consider if we should 

take final action for new residential masonry heaters in a future rulemaking.

The potential emission impact of this delay is small. Fewer than 1,000 masonry 

heaters are built each year. Most manufacturers build fewer than 15 heaters per year. The 

total nationwide annual emissions are estimated to be less than 10 tons of PM2.5.

B. Appliance Certification, Laboratory Accreditation and Third-party Certification

In section III.D of the preamble to the proposed rule, we described the proposed 

approach for a third-party certification program by an ISO-accredited certifying body and 

testing by ISO-accredited testing laboratories. This approach requires manufacturers to 

use third-party, independent ISO-accredited and EPA-approved test labs and certifying 

entities to demonstrate compliance with a representative appliance for a model line. 

Under the Administrator Approval Process (see §60.533(c) of the proposed rule), 

we proposed a transition period of 1 year from the effective date of the final rule for test 

labs to receive ISO accreditation through an EPA-recognized accreditation body. In this 

final rule, we are increasing the transition period for test laboratories that are currently 

EPA-accredited from 1 year to 3 years from the effective date of this final rule (i.e., until 

[INSERT DATE 60 DAYS PLUS 3 YEARS AFTER DATE OF PUBLICATION IN 

THE FEDERAL REGISTER]). This additional time for test laboratory accreditation 

will reduce concerns about costs for these small laboratories and potential testing delays.

We proposed that certifying entities be required to receive ISO accreditation upon 

the effective date of the final rule; however, commenters stated that ISO accreditations 
Page 51 of 326

can take 6 months. Requiring use of ISO-accredited certifying bodies/entities on the 

effective date of the final rule can be difficult for small manufacturers of wood 

stoves/heaters and forced-air furnaces, which previously have not been required to obtain 

certifications from ISO-accredited certifying bodies/entities; therefore, we are allowing a 

6-month transition for models other than hydronic heaters. The 6-month transition period 

does not apply to hydronic heaters because the use of ISO-accredited certifying 

bodies/entities has been part of the EPA’s voluntary partnership program for hydronic 

heaters since 2008. 

C. Cost and Economic Impacts 

Cost and economic impacts of the proposed rule have been revised to reflect 

changes to the standards and improved estimates of costs and emissions for room heaters 

and central heaters. See section VI of this preamble for a discussion of these revised 

impacts, as well as the RIA and the RTC document for this final rule for more detailed 

information.

D. Test Methods and Compliance Certification Calculation Procedures 

The EPA proposed a number of changes to test methods established under the 

1988 rule to improve their precision and to better reflect real-world conditions. 

1. Burn Rates in Compliance Certification Calculations

For Step 2 emission limits, we proposed to require certification compliance at the 

lowest burn rate (Category 1) and the maximum burn rate (Category 4) rather than the 

weighted average of the four burn rates, which was required in the 1988 rule.

Many comments on the proposal and the data in the NODA strongly supported 

the proposed compliance determinations per individual burn rates. Many other comments 
Page 52 of 326

strongly opposed the proposal. Considering all of the comments and focusing on the 

available test data, especially the EPA wood stove certification test data by burn rate that 

we included in the July 1, 2014, NODA, we are requiring certification calculations based 

on the weighted average of the four burn rates for subpart AAA. More detail is presented 

in section V.A, BSER and Particulate Emission Limits for Room Heaters (revised subpart 

AAA), and section V.F, Test Methods.

For subpart QQQQ, the final rule uses the weighted average with a cap for each 

test run for Step 1 (for hydronic heaters), but retains the proposed requirement for 

compliance at each burn rate for Step 2 (for both hydronic heaters and forced-air 

furnaces), given concerns about the sometimes very large emissions at individual burn 

rates. The emission limits reflect the data available. For a more detailed discussion of 

these comments and responses, see the RTC document in the docket for this rule.

2. Cord Wood Test Method

Based on the existence of viable draft cord wood test methods and the expectation 

at proposal that the ASTM “real world” test methods for cord wood would be complete 

soon after the NSPS proposal and that significant testing of wood heaters re-tuned to 

perform well on cord wood would occur before promulgation of this final rule, the EPA 

proposed to require testing only with cord wood for compliance with Step 2 emissions 

limits. We still encourage manufacturers to design wood heaters that perform best on 

cord wood that consumers use. However, the ASTM cord wood test methods have not 

been completed and only limited testing using the draft methods has occurred. We 

received numerous comments from noncatalytic stove manufacturers and laboratories and 

some states with concerns about when the cord wood test methods would be ready and 
Page 53 of 326

how quickly noncatalytic stoves could be redesigned to perform well with cord wood 

certification testing that we proposed for Step 2, i.e., 5 years after the effective date. (We 

had test data for three catalytic or hybrid wood heaters/stoves that performed very well on 

cord wood at the time of proposal.) However, considering all of the above, we have 

determined that we do not have sufficient data at this time to support a regulatory 

requirement for cord wood testing (other than for forced-air furnaces), but rather will 

allow an alternative compliance option for cord wood testing. (Note that forced-air 

furnace certification tests are conducted according to CSA B415.1-10 which has specified 

cord wood as the test fuel since 2010.)

We expect that many manufacturers will choose the alternative cord wood 

compliance testing option so that consumers will have more opportunities to purchase 

stoves that are tuned for use in the “real world.” We will consider alternative cord wood 

test method requests on a case-by-case basis until we are convinced that improved test 

methods have been sufficiently demonstrated that they can be relied upon for regulatory 

purposes. For now, we will be receptive to alternative test methods requests that use the 

current ASTM draft methods. Also, we will be receptive to other alternative test method 

requests that are adequately demonstrated, ideally according to the EPA Method 301 

validation procedures. Additionally, we expect that within the next few years we will 

receive enough cord wood test data for the EPA to establish revised certification 

requirements based on cord wood testing. 

See section III of this preamble for the specific alternative compliance emissions 

limit options we are allowing under subparts AAA and QQQQ for manufacturers of 

heaters who choose to certify compliance with cord wood instead of crib wood. The 
Page 54 of 326

bases for the options are discussed in section V, Summary of Responses to Major 

Comments. 

3. Additional Test Methods

Based on comments and the need to minimize potential testing and certification 

delays for Step 1, the final rule includes additional test methods for hydronic heaters. In 

addition to the proposed use of EPA Method 28WHH and EPA Method 28WHH-PTS, 

the final rule allows manufacturers to use ASTM E2618-13 and EN303-05 with specified 

conditions/adjustments (e.g., burn rate categories to better match EPA Method 28WHH 

and use of thermal storage) for determining compliance with the Step 1 emission limits. 

As with all NSPS, manufacturers may request EPA approval of alternative test methods 

on a case-by-case basis. See 40 CFR 60.8.

E. Sell-through of Inventory

Based on numerous comments from small business manufacturers and small 

business retailers and some states, we are lengthening the retail sell-through period for 

subpart AAA from 6 months from the effective date of the final rule to December 31, 

2015, approximately 8 months from the expected effective date. That is, no manufacturer, 

distributor, wholesaler or retailer may sell or offer to sell new stoves after December 31, 

2015, that do not meet the Step 1 emission limit. Eight months will better cover the 

primary selling period after the rule is final and will affect a very small number of 

appliances. We are also providing a retail sell-through period for subpart QQQQ

hydronic heaters to also cover the primary selling period. We are not allowing a retail 

sell-through period for forced-air furnaces because the manufacturers and retailers can 

quickly revise the owner’s manuals to add best burn practices to comply with the work 
Page 55 of 326

practice and operational standards. These sell-through provisions do not affect resale of 

used stoves/heaters; such resale is not restricted by this rule.

F. Appeals and Administrative Hearing Procedures

Based on the public comments and our additional review of the history of the 

1988 rule, we have determined that there is no need to make the proposed change to a 

streamlined Petition for Review process. Therefore, we are retaining the Appeals and 

Administrative Hearing Procedures outlined in the 1988 rule.

V. Summary of Responses to Major Comments

Detailed summaries are in the RTC document in the docket.

A. BSER and Particulate Emission Limits for Room Heaters (revised subpart AAA) 

We received a full range of comments on the proposed BSER and emission limits

for room heaters and the data in the July 1, 2014, NODA. Many comments agreed 

completely with our proposal and that approximately 10,000 tons/yr of PM2.5 emission 

reduction is very important and would lead to significant improvement in public health 

protection.

Some comments indicated that bans of wood burning would be more appropriate. 

The EPA is not banning wood burning in this rule because section 111(a)(1) of the CAA 

requires that the emission standards reflect the degree of emission limitation achievable 

by the application of BSER. 

Some comments suggested that we develop less stringent standards for rural areas 

than other areas or no standards in rural areas at all. The EPA is not setting different 

emission standards for rural areas because section 111 of the CAA does not provide legal 

authority for differentiated standards based on where the devices are used.
Page 56 of 326

1. Stringency of Step 2 Level Using Cord Wood for Room Heaters

Many noncatalytic stove manufacturers and laboratories and some other 

manufacturers were concerned especially about the stringency of the Step 2 level using 

cord wood 5 years after the effective date. We considered all comments and focused on 

those that discussed the emission data in detail.

Numerous small business manufacturer comments suggested that (1) current stove 

designs are focused on burning crib wood well at the expense of burning “real world”

cord wood well, and stoves cannot just be tweaked to burn both well; (2) experience in 

homes is that some crib wood-certified stoves smolder if the homeowner does not operate 

them at high burn for at least 30 minutes before dampening down to the low burn rate 

settings; (3) a cord wood test method more representative of in-home use should be 

developed as soon as possible; and (4) a voluntary option should be used to establish a 

cord wood database to determine BSER.

As discussed in the NODA, limited cord wood testing by Brookhaven National 

Laboratory (BNL), under contract to the EPA, showed that repeatability of the cord wood 

test method results can sometimes be very good (i.e., within 15 percent). However, the 

results of the BNL cord wood tests also showed that emissions from a popular, 

inexpensive, current-model noncatalytic stove that was not adjusted by the manufacturer 

for burning cord wood instead of crib wood during the certification test can be much 

higher than (in several cases, over twice as high) the crib wood emission test results. 

Other comments suggested that we stay with the proposed cord wood testing 

requirement and proposed Step 2 emission level that some heaters can already meet. For 

example, Washington State Department of Ecology (WSDOE) stated that (1) the data 
Page 57 of 326

show that hybrid stoves are the best technology capable of meeting Step 2, better than 

noncatalytic stoves; and (2) the extensive lack of Category 1 burn rate data in the 

certification tests indicates a “serious flaw” and that EPA needs to develop test methods 

more representative of in-home use that include start-up and the lowest burn rate at which 

a device may be commonly operated. We agree with WSDOE that it appears that hybrid 

stoves may be the best technology capable of meeting Step 2, better than noncatalytic 

stoves; however, we are concerned about setting required emission levels that may have 

potential impacts on a large number of small businesses that may not yet have much 

experience with that technology, and we do not want to prematurely restrict their choices. 

As discussed in section IV.D, we agree that test methods are needed that better reflect inhome use and include start-up and the lowest burn rate at which a device may be 

commonly operated. 

As discussed earlier in this preamble, based on the data and comments, we have 

determined that it is premature to require a cord wood-based Step 2 emission limit at this 

time. Rather, we are basing the Step 2 requirements on crib wood testing and including 

an alternative compliance option to encourage manufacturers to certify with cord wood as 

soon as possible to provide consumers with better information regarding in-home use.

In support of the cord wood alternative compliance option, there are three stove 

model lines that meet Step 2 using cord wood testing. As discussed in section IV.D of 

this preamble, we expect additional manufacturers will choose the alternative cord wood 

compliance testing option so that consumers will have more opportunities to purchase 

stoves that are tuned for in-home use. We will consider alternative cord wood test method 

requests on a case-by-case basis until we are convinced that improved test methods have 
Page 58 of 326

been sufficiently demonstrated that they can be relied upon for regulatory purposes. For 

now, we will be receptive to alternative test method requests that use the current ASTM 

draft methods. We will also be receptive to other alternative test method requests that are 

adequately demonstrated, ideally according to EPA Method 301 validation procedures. 

We expect that within the next few years we will receive enough cord wood test data for 

the EPA to establish revised certification requirements based on cord wood testing.

Commenters overwhelming agree that cord wood testing is a better representation 

of “real world” conditions, provides better information for consumers to choose the 

cleanest and most efficient heaters and that the EPA should encourage cord wood testing. 

Thus, the final rule includes a cord wood alternative compliance option for Step 2 and 

special permanent labels and allows (voluntary) temporary EPA labels (hangtags) for 

units tested with cord wood. As discussed earlier in this section, the proposal reasonably 

anticipated that all manufacturers would iteratively adjust the combustion air flows, 

directions and proportions to better match the change in hydrocarbon volatilization rate 

due to the difference in surface-area-to-volume ratio and spacing for crib wood versus 

cord wood. The proposal also reasonably anticipated that manufacturers would have a 

full complement of cord wood tested heaters available by Step 2, i.e., 5 years after the 

effective date. Some stoves already perform well on cord wood. However, comments 

from some small business noncatalytic stove manufacturers, small business laboratories 

and some states have questioned whether most small business manufacturers could 

comply with the Step 2 emission limits based on cord wood by that date. As discussed in 

the NODA, the cord wood test data submitted to us for three catalytic or hybrid wood 

stoves manufactured by two small businesses show that their EPA-certified wood stoves
Page 59 of 326

(when tested using cord wood and making no design changes to adjust for testing using 

cord wood versus crib wood) have similar emissions as their stoves do when tested using 

crib wood. The cord wood results show that they can achieve an emission limit of 1.3 

g/hr, as proposed. Several comments stated that they did not believe these results are 

representative of most EPA-certified stoves and that typical cord wood values are likely 

to be higher than the 1.3 gr/hr level, as well as the 2.0 g/hr level of the final crib wood

Step 2 emission level or any other crib wood level. 

Recognizing that the cord wood alternative compliance option is an option rather 

than a requirement, we have set the cord wood Step 2 emission level at 2.5 g/hr as the 

alternative compliance option for room heaters for the following reasons: 

 Test data show that at least three wood stoves meet a limit of 1.3 g/hr, which

(coupled with some commenters’ claims that the test precision is no better than 1.0 g/hr) 

would suggest an achievable limit on the order of 2.3 g/hr. 

 The State of Washington DOE has required catalytic stoves since 1995 to meet a 

limit of 2.5 g/hr.

 The Step 2 emission level does not take effect until 5 years after the effective date 

of this final rule. 

The cord wood alternative compliance option provides appropriate opportunities to small 

manufacturers who have been leaders in optimizing for cord wood performance and 

encourages other manufacturers to follow their example. More discussion is in the RTC 

document in the docket for this final rule.

2. Stringency of Step 2 Level Using Crib Wood for Room Heaters 
Page 60 of 326

We have set the crib wood Step 2 emission limit at 2.0 g/hr for the following 

reasons: 

 Focusing on the comments that discussed the details of the crib wood certification 

test data for Step 2, nearly 90 percent of current catalytic/hybrid stoves and over 18 

percent of current noncatalytic stoves would meet the Step 2 emission limit of 2.0 g/hr in 

the final rule. This compares to 20 percent of catalytic/hybrid wood heaters/stoves and

only 3 percent of noncatalytic wood heaters/stoves for the proposed 1.3 g/hr Step 2 

emission limit.

 Considering that current stove sales are approximately 20 percent catalytic/hybrid 

stoves and 80 percent noncatalytic stoves, the estimated impact of adjusting the Step 2

emission level from 1.3 g/hr to 2.0 g/hr will be to decrease the emission reduction 

estimated for this rule by approximately 36 tons per year, which is relatively small 

compared to the rule’s total estimated emission reduction of 8,269 tons per year. 

Furthermore, the impact for any individual stove is only on the order of 2 pounds per 

year.

 The final Step 2 emission limit of 2.0 g/hr is more stringent than any current state 

requirement. 

Thus, considering the significant emission reductions for this final rule and the 

potential significant cost impacts for this industry that is comprised of over 90 percent 

small businesses, and considering that the difference between the proposal and this final 

rulemaking is less than approximately 36 tons per year compared to the 8,269 tons per 

year for this final rulemaking, we judge that a final Step 2 emission level of 2.0 g/hr 
Page 61 of 326

within 5 years as BSER for room heaters is a reasonable balance of environmental 

impacts and costs.

3. Determination of BSER for Room Heaters

Some comments questioned that BSER is adequately demonstrated. The data in 

the paragraph above show that not only are the emission levels demonstrated, the 

percentages of current heaters that already meet Step 2 demonstrate the reasonableness of 

the Step 2 emission limit, especially considering that the Step 2 emission limit becomes 

applicable 5 years after the effective date.

Some comments recommended that the final rule be as stringent as the cleanest 

stoves on the market and some comments suggested numbers that reflect the top 5 

percentile. Section 111 of the CAA does not specify any particular floor for BSER 

determinations but does require consideration of costs. As discussed above, considering 

that the emission reduction difference between the proposal and this final rulemaking is 

approximately 36 tons per year (compared to the 8,269 tons per year for this final 

rulemaking), we judge that a final Step 2 BSER of 2.0 g/hr within 5 years is a reasonable 

balance of environmental impacts and costs.

Some comments suggested that the precision of the test method is not good 

enough to set emission limits more stringent than the 1988 NSPS. In response, we note 

that the State of Washington DOE has successfully required a 2.5 g/hr emission limit for 

catalytic stoves since 1995, and several stoves have been EPA-certified at 1.0 g/hr, which 

is well under the final Step 2 emission limit of 2.0 g/hr. Even if the commenters’ claims 

were correct that the precision is no better than 1.0 g/hr, the final emission limit of 2.0 

g/hr would still cover these stoves, i.e., 1.0 g/hr plus 1.0 g/hr equals 2.0 g/hr, the step 2 
Page 62 of 326

emission limit. Further, we note that the final rule deletes the previously required upward 

adjustment for Method 5G to 5H, which was sometimes over a 30 percent increase for 

certification values (under the 1988 NSPS and the State of Washington DOE) that were 

tested using Method 5G.

B. BSER and Particulate Emission Limits for Central Heaters (subpart QQQQ)

Comments of many small business manufacturers of hydronic heaters and forcedair furnaces questioned the demonstrations of BSER for hydronic heaters and forced-air 

furnaces, especially the proposed cord wood Step 2 limit of 0.06 lb/mmBtu. As discussed

earlier in sections III.B and III.C of this preamble, considering the numerous comments 

expressing concern about whether most small business manufacturers will be ready in 

time, reviewing the data currently available, and acknowledging that the expected ASTM 

cord wood test methods are not yet completed at this time, we have determined that it is 

premature to require cord wood certification tests for hydronic heaters at this time. 

Rather, we are allowing a cord wood alternative compliance option.

1. Stringency of Step 1 Level Using Crib Wood for Central Heaters

Focusing on the crib wood test primary requirement and crib wood test data, we 

see that there are already 50 hydronic heater models Phase 2 qualified under the EPA 

hydronic heater voluntary partnership program, which also meet the Step 1 emission 

levels of this final NSPS. These models will be automatically deemed EPA-certified for 

Step 1 of this final NSPS. (There are also 19 voluntary program qualification tests 

recently submitted to the EPA that, if valid, will result in 19 additional Phase 2 model 

qualifications.) Similarly, models certified by the NYSDEC that comply with Step 1 will 

also be automatically deemed EPA certified until Step 2. Also, over 20 pellet 
Page 63 of 326

heaters/boilers are already qualified under the RHNY program, and they will be 

automatically deemed to be EPA-certified for Step 1 provided they comply with the 

RHNY requirements for installation and operation with adequate thermal storage. That is, 

no additional certification will be necessary for these three groups for Step 1.

For forced-air furnaces, commenters indicated that the Step 1 PM emission limit 

was achievable but small furnaces needed 1 year and large furnaces needed 2 years to 

complete the certification testing. As discussed earlier, the final rule incorporates the 

necessary additional time for testing. 

2. Stringency of Step 2 Level Using Crib Wood for Central Heaters 

For new residential hydronic heaters, we have set the crib wood Step 2 emission 

level at 0.10 lb/mmBtu based on the following:

 Looking at the crib wood test primary requirement for Step 2 (0.10 lb/mmBtu), 9 

of the 50 (18 percent) EPA-qualified hydronic heater models currently achieve Step 2 on 

crib wood (per run); and all 20 of the RHNY-qualified models achieve 0.10 lb/mmBtu. 

 The proposed Step 2 level (0.06 lb/mmBtu) currently is achieved only by 3 of the 

49 (6 percent) EPA-qualified models (per run). 

 The emission reduction difference between the proposed Step 2 hydronic heater 

emission level (0.06 lb/mmBtu) and the final Step 2 hydronic heater emission level (0.10 

lb/mmBtu) is approximately only 15 tons per year (compared to the 8,269 tons per year 

for this final rulemaking). 

Considering the potential significant cost impacts for this industry that is 

comprised of over 90 percent small businesses, and that the relatively small difference in 

emission reductions between the proposal and this final rulemaking, we judge that a final 
Page 64 of 326

hydronic heater Step 2 emission level of 0.10 lb/mmBtu within 5 years as BSER is a 

reasonable balance of environmental impacts and costs.

3. Stringency of Step 2 Level Using Cord Wood for Central Heaters

As with room heaters (subpart AAA) and for the same reasons, hydronic heaters 

(subpart QQQQ) have a cord wood alternative compliance option. Considering that it is 

an option designed to encourage leadership for others to follow, that it is an option rather 

than a requirement and that many European models already achieve levels better than 

0.06 lb/mmBtu, we have determined that 0.15 lb/mmBtu within 5 years as the cord wood 

alternative compliance option is a reasonable balance of environmental impacts and costs. 

We note that the RHNY emission qualification requirement is 0.08 lb/mmBtu. Further, 

we note that even if there were to be method uncertainty on the order of approximately 

four times the expected precision of 35 percent, models at 0.06 lb/mmBtu would still be 

included.

We have set the same final Step 2 emission level for forced-air furnaces as BSER

as we have for hydronic heaters based on the following:

 The emission reduction difference between the proposed forced-air furnace Step 2 

emission limit of 0.06 lb/mmBtu and this final rulemaking (0.15 lb/mmBtu) is 

approximately 40 tons per year (compared to 8,269 tons per year emission reduction for 

this final rulemaking). The difference is slightly larger for forced-air furnaces compared 

to hydronic heaters because the annual sales of forced-air furnaces are much larger (i.e., 

41,000 versus 13,000). 
Page 65 of 326

 We considered the potential significant cost impacts for this industry that is 

comprised of over 90 percent small businesses, as well as the modest difference between 

the environmental impacts of the proposal and this final rulemaking. 

Therefore, for forced-air furnaces, we judge that a final Step 2 emission level of 0.15

lb/mmBtu within 5 years as BSER is a reasonable balance of environmental impacts and 

costs.

Since forced-air furnaces and indoor hydronic heaters compete in the same 

market, wise consumers expect similar performance. We expect most forced-air furnace 

manufacturers to transfer technology and knowledge from wood stoves and hydronic 

heaters. Some small forced-air furnaces have already transferred technology from wood 

heaters to achieve good performance. Several industry comments questioned their ability 

to transfer technology from hydronic heaters because of their concerns about size 

limitations in order to install forced-air furnaces indoors going through doorways and 

other entrances to basements. They were especially concerned that the space limitations 

may affect their ability to adequately insulate the models that may be installed in close 

proximity to combustibles. We acknowledge their concerns but note that coal, oil and 

natural gas forced-air furnaces and indoor hydronic heaters that have similar space 

limitations and proximity to combustibles conditions have successfully handled those 

concerns for many years. For example, numerous cord-wood-fired indoor hydronic 

heaters have been safely installed without large volumes of thermal insulation around the 

firebox

C. Appliance Certification
Page 66 of 326

Many comments stressed the importance of easy public availability of 

certification test reports (especially electronically), limited CBI claims, more details on 

the EPA web sites, better labels and more outreach to encourage change outs to cleaner 

stoves. We agree with these comments and the final rule incorporates this transparency 

and consumer-friendliness. Some comments suggested wording clarifications that we 

have incorporated in the final rule. More details are in the RTC document included in the 

docket for this rule.

D. Laboratory Accreditation, Third-party Certification and Administrative Approval 

Process

Many comments stressed the importance of credible data for the certifications and 

the value of close EPA oversight, notwithstanding the addition of ISO-accredited 

laboratories and ISO-accredited certifying entities. Some comments suggested that the 

EPA should allow the ISO-accredited certifying entities to issue NSPS certificates 

directly and that the EPA’s role should be solely to review the certifications and only 

question their certificates upon cause. The small business laboratories requested more 

time for the transition to ISO-accreditation because of the cost. As discussed earlier in 

this preamble, the final rule allows a 3-year extension of current EPA accreditations of 

laboratories and allows 6 months for ISO accreditation of certifying entities, except for 

hydronic heaters, which have used ISO-accredited certifying entities since October 2008 

for the EPA voluntary program. The EPA will retain its approval and oversight functions 

for this final rule. As also discussed earlier in this preamble, to address the possibility that 

there may not be sufficient third-party certifier capacity and review and approval capacity 

by the EPA, especially in the first year, and so as to avoid unfairly restricting the 
Page 67 of 326

production and sales of manufacturers who do all the things they should do and then 

potentially have to wait on the EPA approval, we have added a conditional, temporary 

approval by the EPA for room heaters subject to revised subpart AAA, as well as forcedair furnaces subject to subpart QQQQ, based on the manufacturer’s submittal of a 

complete certification application. The application must include the full test report by an 

EPA-accredited laboratory and all required compliance statements by the manufacturer. 

The conditional approval would allow manufacture and sales for 1 year or until EPA 

review of the application, whichever is earlier. Within 1 year, the manufacturer must 

submit a certificate of conformity by a third-party certifier. 

The 1-year conditional, temporary approval by the EPA does not apply to 

hydronic heaters because they have used third-party certifications for the voluntary 

program since 2008 and will continue to do so under the NSPS.

E. Costs and Economic Impacts

1. Costs

Comments received on the proposed rule included information and opinions 

regarding the EPA wood heater cost estimates.8 Comments ranged from criticism that the 

EPA overestimated costs to criticism that the EPA underestimated costs. The comments 

that provided data and/or analysis explaining why the commenter thought EPA had not 

accurately estimated the costs were most persuasive, and we have revised our cost 

estimates based on those detailed comments. Details of our responses to cost comments 

are in the RTC document and the technical cost memoranda in the docket for this final 

rule. 

 

8 Comments on the proposed NSPS are available electronically through 

http://www.regulations.gov by searching Docket ID EPA-HQ-OAR-2009-0734.
Page 68 of 326

a. Room Heaters

For example, Washington State Department of Ecology stated that the proposal 

cost estimates were overestimates and that our estimates did not address input from 

Woodstock Soapstone Stoves, winner of the 2013 Wood Stove Decathlon, which 

estimates that the cost of new product development is approximately $200,000, and 

furthermore that the proposal cost estimates did not address the economies manufacturers 

realize when they develop functionally identical models from the originally certified 

model.9 Some other commenters generally stated that EPA’s breakdown of cost estimates 

faced by manufacturers is inaccurately low. We have considered all the comments and 

have revised our cost estimates based on comments that provided additional detailed cost 

data.

Prior to proposal, we heard various estimates of the costs to bring a wood heater 

from concept to completion, from $200,000 for a single model to $1,360,000 for a 4-

firebox model line. For example, a Hearth and Home article estimated the total cost to 

bring a model from conception to market as $645,000 to $750,000 for steel stoves and 

over $1 million for cast-iron, enameled wood stoves. The authors indicated that costs 

would decrease for separate models in the same line by up to 25 percent. Based on this 

information, we estimated that a 4-model steel line would cost up to $328,125 per model 

to develop. These costs include marketing, design, developing first generation, second 

generation and prototype units; NSPS and safety testing, equipment tooling, etc.10 Two 

 

9 Comment on the proposed rule to Docket EPA-HQ-OAR-2009-0734 from the 

Washington State Department of Ecology; available at 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OAR-2009-0734-1397. 

10 James E. Houck and Paul Tiegs. There’s a Freight Train Comin’. Hearth and Home. 

December 2009.
Page 69 of 326

other manufacturers also provided estimated development costs for a 4-box model line, 

and based on that information at proposal we estimated average costs to develop a new 

model line, including testing with both crib wood and cord wood and reporting and 

recordkeeping, of $356,250 for certified wood stoves and pellet stoves. We also 

estimated $356,250 for single burn rate stoves, forced-air furnaces and hydronic heaters.

The Hearth Patio and Barbecue Association (HPBA) provided detailed estimates 

of adjustable burn rate wood stoves and hydronic heater model development costs. 

According to HPBA, the proposal cost estimates are deficient because they do not reflect 

specific emission rates or emission performances. Their detailed wood stove cost 

estimates are located in Attachment 2 of the HPBA comments and were prepared by 

National Economic Research Associates (NERA) Economic Consulting (May 2014).11

Appendix A of the document, Woodstove Cost Modeling (prepared by Ferguson, Andors 

& Company) contains the detailed cost estimates we reviewed and adapted for this 

analysis.12

The Ferguson analysis provides cost estimates for four categories of emission 

reductions based on the proposed emission levels, consisting of modifying 7.5 g/hr stoves 

to comply with a new 4.5 g/hr emission limit, modifying the 4.5 g/hr stoves to comply 

with new emission limits of 2.5 g/hr or 1.3 g/hr stoves, and modifying a 2.5 g/hr stove to 

a new emission limit of 1.3 g/hr. The resulting cost components consisted of capital costs 

per model (R&D, engineering labor, tooling, equipment integration, preliminary testing, 

 

11 Comment on the proposed rule to Docket EPA-HQ-OAR-2009-0734 from the Hearth, 

Patio and Barbecue Association available at 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OAR-2009-0734-1643

12 Ferguson, Robert (Ferguson, Andors & Company), prepared for the Hearth, Patio & 

Barbecue Association. Proposed Wood Heater NSPS Incremental Cost Effectiveness 

Analyses, Appendix A: Woodstove Cost Modeling. May 2014. p.1.
Page 70 of 326

and other costs to design and manufacture the modified wood stove model) and other 

fixed costs per model (certification testing and safety testing, roll-out of the modified 

products including store display models and burn programs, brochures, user manuals, 

training and product discounts). The mid-point capital costs presented by Ferguson range 

from $281,725 to $532,050 depending on the emission reduction range.13

As discussed earlier in section III.A, unlike the proposed rule, the final subpart 

AAA rule only contains a Step 1 PM emission limit of 4.5 g/hr and a Step 2 PM emission 

limit of 2.0 g/hr, with no alternative, three-step emission limits. The comments 

overwhelmingly indicated that the three-step emission limit approach was inferior not 

only environmentally but also economically because it would, in effect, require many 

small manufacturers to engage in two rounds of R&D rather than one in order to obtain 

the same eventual endpoint.

The Step 1 cost for 7.5 to 4.5 g/hr is a reasonable representation of model 

development costs for all models subject to subpart AAA, with some exceptions, 

described below. The Ferguson analysis shows that several of the cost components are 

identical across scenarios. The analysis claims, however, that other cost components vary 

according to the specified emission reduction scenario. These differences were not 

supported in the comments. For purposes of this analysis, we used the 7.5 to 4.5 g/hr 

scenario as a baseline case and modified it to reflect the deletion of cost categories that 

were inappropriate for the NSPS analyses, e.g., costs for trips to industry trade shows that 

would occur for all products regardless of the NSPS.

 

13 Ferguson, Robert (Ferguson, Andors & Company), prepared for the Hearth, Patio & 

Barbecue Association. Proposed Wood Heater NSPS Incremental Cost Effectiveness 

Analyses, Appendix A: Woodstove Cost Modeling. May 2014. pp. 4 – 5.
Page 71 of 326

We did accept the assumptions and logic related to evaluating the tooling cost 

difference between steel stoves and cast iron stoves, as both are commonly manufactured. 

Like Ferguson, we used an average of their tooling costs to reflect product differences, 

even though this may overestimate the number of cast iron stoves in the market place. 

While we recognize the range in capital cost estimates provided both prior to and after 

proposal of the draft standards leave room for additional cost scenarios, especially the 

much lower cost scenario for Woodstock Soapstone Stoves, the Ferguson costs represent 

the best documented cost ranges and cost categories available at this time.

For the final cost analysis, we used the mean wood stove costs. For our analyses, 

these model development costs represent feasible costs for adjustable burn rate stoves and 

pellet stoves. For single burn rate stoves, as we did at proposal, the analyses reflect that 

additional R&D may be required to bring these stoves to qualifying levels. Rather than 

doubling the total model development costs during the first 2 years as we did at proposal, 

the new costs for the R&D/Engineering cost portion of the total costs are doubled in the 

first 2 years, with “normal” model development proceeding thereafter.

Details of our responses to cost comments are in the RTC document and the 

technical and cost memoranda in the docket for this final rule. 

b. Central Heaters

At proposal, our analyses reflected that hydronic heaters and forced-air furnaces 

would face the same model development costs as room heaters. Some commenters 

objected to this characterization, particularly based on the detailed hydronic heater cost 

estimates located in Attachment 3 of the HPBA comments as prepared by NERA 
Page 72 of 326

Economic Consulting (May 2014).14 Appendix A of that document, Hydronic Heater 

Cost Modeling (prepared by Ferguson, Andors & Company) contains the detailed cost 

estimates we reviewed and adapted for this analysis. 

The HPBA costs for hydronic heaters were prepared with the same methodology 

and overall assumptions as they used in development of the wood heater costs. The 

Ferguson analysis provides cost estimates for four categories of hydronic heater emission 

reductions, based on the proposed emission levels consisting of modifying uncontrolled 

heaters to comply with a new 0.32 lb/mmBtu emission limit, modifying the 0.32 

lb/mmBtu heaters to comply with new emission limits of 0.15 or 0.06 lb/mmBtu, and 

modifying a 0.15 lb/mmBtu heater to a new emission limit of 0.06 lb/mmBtu. The 

resulting cost components consisted of capital costs per model (R&D, engineering labor, 

tooling, equipment integration, preliminary testing, and other costs to design and 

manufacture the modified wood stove model) and other fixed costs per model 

(certification testing and safety testing, roll-out of the modified products including store 

display models and burn programs, brochures, user manuals, training and product 

discounts). The mid-point capital costs presented by Ferguson range from $1,743,750 to 

$2,162,300 depending on the emission reduction range.15 We used these cost estimates in 

our analysis.

As discussed earlier in section III.A, unlike the proposed rule, the final rule 

contains a Step 1 PM emission limit of 0.32 lb/mmBtu and a Step 2 PM emission limit of 

 

14 Comment on the proposed rule to Docket EPA-HQ-OAR-2009-0734 from the HPBA 

available at http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OAR-2009-

0734-1643.

15 Ferguson, Robert (Ferguson, Andors & Company), prepared for HPBA. Proposed 

Wood Heater NSPS Incremental Cost Effectiveness Analyses, Appendix A: Hydronic 

Heater Cost Modeling. May 2014. p. 4.
Page 73 of 326

0.10 lb/mmBtu, with no alternative three-step PM emission limits. The comments 

overwhelmingly indicated that the three-step PM emission limit approach was inferior 

not only environmentally but also economically because it would, in effect, require many 

small manufacturers to engage in two rounds of R&D rather than one in order to obtain 

the same eventual endpoint.

The Step 1 PM emission limit cost for modifying uncontrolled heaters to comply 

with 0.32 lb/mmBtu is a reasonable representation of model development costs for all 

models subject to subpart QQQQ, with some exceptions, described below. The Ferguson 

analysis shows that several of the cost components are identical across scenarios. The 

analysis claims that other cost components vary according to the specified emission 

reduction scenario; however, no support was provided for these claims in the Ferguson 

analysis. For purposes of our analysis, we used the scenario of uncontrolled to 0.32 

lb/mmBtu as a baseline case and modified it to reflect the deletion of cost categories that 

were inappropriate for the NSPS impact analyses, e.g., costs for trips to industry trade 

shows that would occur for all products regardless of the NSPS.

For our final rule cost analysis, we used the mean hydronic heater costs estimated 

in Table 5-2 of the final RIA. These model development costs represent feasible costs for 

hydronic heaters. For forced-air furnaces, as we did at proposal, our analysis included the 

additional R&D that may be required to bring these heaters to qualifying levels. Rather 

than doubling total model development costs during the first 2 years as we did at 

proposal, for the final rule analysis the R&D/Engineering cost portion of the total costs 

are doubled in the first 2 years, with “normal” model development proceeding thereafter.
Page 74 of 326

Details of our responses to cost comments are in the RTC document and the 

technical and cost memoranda in the docket for this final rule. 

2. Economic Impacts 

As discussed in detail in the RIA and summarized in section D.1 above, we 

received numerous comments on the costs, and we have adjusted our cost estimates as 

appropriate. Since the economic impacts are based on the costs and other factors, we have 

adjusted the economic impacts accordingly. The details of the adjustments are in the RIA, 

and a summary is in sections IV.C and VI of this preamble.

F. Test Methods

1. Crib Wood vs. Cord Wood

We received a full range of comments on this issue, from complete support for the 

proposed cord wood testing requirements to complete opposition to requiring cord wood 

testing at this time. We considered all comments and focused on those that discussed the

data in detail. As discussed earlier in section IV, based on the data and comments 

submitted, we have determined that it is premature to require a cord wood-based Step 2 

PM emission limit at this time (except for forced-air furnaces for which CSA B415.1-10 

already specifies cord wood as the test fuel). Rather, we are basing the Step 2 PM 

emission limit on crib wood testing and including an alternative compliance option to 

meet an emission limit based on cord wood testing, to encourage manufacturers to certify 

with cord wood as soon as possible to provide consumers with better information for their 

actual in-home-use performance. There are some manufacturers that already achieve the 

cord wood emission level and we expect that many more manufacturers will take this 
Page 75 of 326

option and submit data that will inform development of a required cord wood 

certification test in a future rulemaking.

Based on the existence of a viable draft cord wood test method and the 

expectation at proposal that the ASTM test methods for cord wood would be complete 

soon after proposal and that significant testing of wood heaters re-tuned to perform well 

on cord wood would occur before promulgation of this final rule, the EPA proposed to 

require testing only with cord wood for compliance with Step 2 emissions limits. We still 

encourage manufacturers to design wood heaters that best represent actual in-home-use 

performance on cord wood. However, the ASTM cord wood test methods have not been 

completed and only limited testing using the draft methods has occurred. For the cord 

wood alternative compliance option, we will consider approval of requested test methods 

on a case-by-case basis. We believe the current draft ASTM test methods are sufficient to 

be used, upon request, for the cord wood alternative compliance option until better test 

methods can be developed. We will also be receptive to other alternative test method 

requests that are adequately demonstrated, ideally according to the EPA Method 301 

validation procedures. (Note that forced-air furnaces are tested according to the cord 

wood test method already specified in CSA B415.1-10.

2. Compliance for Individual Burn Rates Versus Weighted Averages

We received a full range of comments on this issue, from complete support for the 

proposed Step 2 compliance for individual burn rates to using only the weighted averages 

similar to the 1988 NSPS. We considered all comments and focused on those that 

discussed the data in detail. As mentioned earlier in section IV, based on the data and 

comments submitted, we have determined that the final rule will require weighted 
Page 76 of 326

averages for Step 2 in subpart AAA and individual burn rates for Step 2 in subpart 

QQQQ.

For subpart AAA Step 2 emission limits, we proposed to require certification 

compliance at the lowest burn rate (Category 1) and the maximum burn rate (Category 4) 

rather than the weighted average of the four burn rates, which was required in the 1988 

rule. Many comments on the proposal and the data in the NODA strongly supported the 

proposed compliance determinations per individual burn rates. Many other comments 

strongly opposed the proposal. Considering all of the comments and focusing on the 

available test data, especially the EPA wood stove certification test data by burn rate that 

we included in the July 1, 2014 NODA, we are requiring certification calculations based 

on the weighted average of the four burn rates for subpart AAA. As discussed earlier in 

section V.A, the data show that for weighted averages, 18 percent of noncatalytic stoves 

(that represent over 80 percent of the market) achieve 2.0 g/hr. However, on an individual

burn rate basis, only 6 percent (7 of 110 stoves) achieve 2.0 g/hr, a relatively small 

percentage of wood stoves manufactured today. This supports our decision that a Step 2 

limit of 2.0 g/hr, based on a weighted average of the multiple burn rates, better represents 

BSER for wood stoves/heaters subject to revised subpart AAA, compared to a Step 2 

limit based on individual burn rates.

For subpart QQQQ, the final rule retains the proposed Step 1 g/hr emission cap 

for all burn rates (for hydronic heaters) and the Step 2 requirement for lb/mmBtu 

compliance at each burn rate (for both hydronic heaters and forced-air furnaces) given

concerns about the sometimes very large emissions at individual burn rates. The emission 
Page 77 of 326

limits reflect the data available. For a more detailed discussion of these comments and 

responses, see the RTC document in the docket for this rule.

3. National Technology Transfer and Advancement Act (NTTAA)

We received a full range of comments on this issue, from complete support to 

adamant disagreement with our determinations under the NTTAA at proposal that some 

portions of some of the ASTM test methods were not applicable or impractical for this 

rule because they did not achieve the Agency’s mission, goals and objectives. (The 

NTTAA directs agencies to use voluntary consensus standards whenever applicable 

methods are available unless they are impractical.) As discussed in the proposal preamble 

in section VI.I, the rule incorporates some voluntary consensus standards (VCS) by 

reference, including some ASTM methods and CSA B415.1-10. We could not use some 

ASTM test methods and other VCS because they were not applicable. That is, the 

inapplicable VCS did not fully achieve the intent of this rule or the primary mission of 

the Agency and many tribes, states and local agencies to protect human health and the 

environment.

Some comments claimed that the EPA cannot take portions of VCS but rather 

must only use the whole VCS. That position is inconsistent with the intent of the NTTAA 

goal for reducing duplication of effort. That is, using valuable portions of VCS helps 

reduce potential duplicative efforts.

Some comments suggested that because the EPA unofficial participants (the EPA 

employees who were not ASTM members but participated in some of the calls) in certain 

ASTM test method development efforts did not submit official negatives on the standard, 

that somehow that meant that the EPA approved all of the details of the draft ASTM test 
Page 78 of 326

methods. The EPA participants often expressed that the draft test methods were not fully 

applicable to the needs of the EPA and states; but since the draft test methods may meet 

some of the immediate needs of the industry participants, the EPA did not want to stop 

the ASTM efforts to develop improved drafts. Further, the NTTAA guidance explicitly 

states that Agency participation does not indicate Agency approval or endorsement. 

4. Real World, Cold Starts, Cycling, Moisture, Heat Demand 

Many comments indicated a critical need for test methods that reflect the “real 

world” with cord wood, cold starts, cycling, moisture, heat demand and shorter averaging 

periods.

We strongly agree, and we will consider alternative cord wood test method 

requests on a case-by-case basis until we are convinced that improved test methods have 

been sufficiently demonstrated that they can be relied upon for regulatory purposes

Additionally, we expect that within the next few years we will receive enough “real 

world” cord wood test data for the EPA to establish revised certification requirements 

based on those test data.

G. Health Effects and Benefits

A more detailed summary of the comments is in the RTC document in the docket.

1. Additional Health Outcomes

Several comments suggested that the EPA should expand its assessment of health 

benefits.

The RIA includes all possible health impacts related to exposure to wood 

combustion-related PM2.5. Table 7-1 of the RIA on human health effects of ambient 

PM2.5 has an extensive list of the above mentioned health endpoints that were considered 
Page 79 of 326

and monetized, including exacerbation of asthma among children. However, several were 

assessed qualitatively due to time and resource limitations. Table 7-2 of the RIA shows 

the results of the assessed health incidence reductions and related benefits from reduced 

PM2.5 exposure associated with the proposed option.

2. Additional Pollutants and Outcomes

Comments suggested that the EPA should expand its assessment to include 

benefits of reductions in CO and VOC and certain non- human health-related benefits 

including: environmental degradation; accelerated depreciation of capital; haze; 

contribution to anthropogenic climate change; and harm to pets and livestock.

The EPA understands that the benefits assessment in the RIA reflects only a 

subset of the benefits attributable to the health effects reductions associated with ambient 

fine particles. Limitations in data, time and resources prevented the EPA from 

quantifying the impacts to, or monetizing the benefits from, several important benefits 

categories, including benefits associated with the potential exposure to ozone formation 

due to VOC emissions as a precursor, VOC emissions as a PM2.5 precursor, CO, as well 

as ecosystem effects, and visibility impairment due to the absence of air quality modeling 

data for these pollutants among others in this analysis. However, the EPA provided an 

extensive qualitative assessment of those benefits. The EPA realizes that the benefits 

presented are an underestimate of the overall benefits resulting from this rule and that 

these reductions will help with ozone and PM planning.

3. Additional Benefits of Reducing Greenhouse Gases

Comments suggested that we expand the benefits analyses to include the benefits 

of reducing greenhouse gases.
Page 80 of 326

The EPA agrees that there will be added benefits from assessing impacts of 

emission reductions of carbon dioxide (CO2), methane and black carbon. While we know 

that these emissions will be reduced along with the reductions of PM emission and the 

increases in efficiency of the affected heaters, we do not have robust emissions test data 

to make quantitative benefits analysis on climate change at this time.

One commenter referred to the interagency Social Cost of Carbon (SCC) 

estimates. The comment suggested that (1) EPA should use SCC to reflect the monetized 

CO2 impacts of the proposed rule in the RIA; and (2) EPA should use the SCC estimates 

published in 2010 instead of the updated SCC estimates published in 2013 because the 

updated estimates have not been subject to public comment. The SCC represents the 

monetized net damages of incremental changes in the amount of CO2 emissions in a 

given year. Given that CO2 impacts of the proposed rule were not analyzed, the SCC 

estimates were not used in the RIA. 

4. Uncertainty of “Value per Statistical Life”

Commenters stated that the EPA’s use of the Value per Statistical Life (VSL) –

that is, the monetized value attributable to mortality reduction – is a source of 

uncertainty.

While the Agency is updating its guidance by incorporating the most up-to-date 

literature and recent recommendations from the Science Advisory Board Environmental 

Economics Advisory Committee (SAB-EEAC), it has determined that a single, peerreviewed estimate applied consistently best reflects the SAB-EEAC advice until updated 

guidance is available. Therefore, the EPA, after consulting with the Office of 
Page 81 of 326

Management and Budget (OMB), has decided to use the value established in the 2000 

Guidelines for all the EPA actions until a revised estimate can be fully vetted.

The EPA will continue to look into approaches based on the best available science 

as appropriate. The EPA will continue to recommend the central estimate of $7.4 million 

($2006), updated to the year of the analysis, be used in all benefits analyses that seek to 

quantify mortality risk reduction benefits regardless of the age, income, or other 

population characteristics of the affected population until revised guidance becomes 

available. This approach was vetted and endorsed by the Agency when the 2000 

“Guidelines for Preparing Economic Analyses” were drafted. Although $7.4 million 

($2006) remains EPA's default guidance for valuing mortality risk changes, the Agency 

has considered and presented others and may well consider the commenter 

recommendation in future assessments.

We agree that there is uncertainty. Recent analyses have estimated substantial 

increases in life expectancy and the number of life years gained due to improved PM2.5

air quality. For example, Hubbell (2006) estimated that reducing exposure to PM2.5 from 

air pollution regulations may result in an average gain of 15 years of life for those adults 

prematurely dying from PM2.5 exposure. In contrast, Pope et al. (2009) estimated changes 

in average life expectancy at birth over a 20-year period, suggesting that reducing 

exposure to air pollution may increase average life expectancy at birth by approximately 

7 months, which was 15 percent of the overall increase in life expectancy at birth from 

1980 through 2000.

5. Uncertainty in the EPA Analyses Regarding the Constant Benefits-per-ton

Simplifying Assumption, Dose-response Relationship, and Benefits Transfer 

Approach
Page 82 of 326

Comments suggested that the relationship between pollution and human health is 

more complex than the EPA’s simplifying assumptions and thus more uncertain.

The EPA’s methods for quantifying health benefits of emission reductions are 

based on the best available peer-reviewed science and methods that have withstood 

scrutiny from the EPA’s independent Science Advisory Board (SAB), the National 

Academy of Sciences (NRC, 2002), and continuous interagency review.

The RIA references a peer-reviewed manuscript and technical support document 

(TSD) that each describe the methods EPA employed to quantify the per-ton benefit of 

reducing fine particle levels from various sources. The air quality modeling attributed 

fine particle levels to residential wood heaters, holding all other sectors constant--giving 

us greater confidence that we have correctly characterized the air quality and health 

impacts attributable to this sector. 

With respect to the incidence of benefits among populations living in locations 

already attaining the primary NAAQS, the EPA acknowledges that primary NAAQS are 

set at a level deemed by the EPA Administrator to be protective of public health with an 

adequate margin of safety. At the same time, primary NAAQS are not set at a level of 

zero risk and there is no known threshold below which PM2.5 does not cause adverse 

health effects. Thus, the EPA recognizes that reducing the emissions level in those areas 

could still have health benefits.

Additional detail of our responses is included in the final RIA.

VI. Summary of Environmental, Cost, Economic, and Non-Air Health and Energy 

Impacts

The EPA estimates the total annualized average nationwide costs associated with 

this rule would be $45.7 million ($2013) over the timeframe of 2015 through 2020. The 
Page 83 of 326

economic impacts for industries affected by this rule over this same period, estimated as a 

percent of annual compliance cost to sales, range from 1.1 percent for manufacture of 

pellet stove models to 17.1 percent for manufacture of hydronic heater models. These 

impacts do not presume any pass-through of impacts to consumers. With pass-through to 

consumers, these impact estimates to manufacturers will decline proportionate to the 

degree of pass-through.

A. What are the Air Quality Impacts? 

In section IV of the preamble to the proposed rule, we described the procedure we 

used to determine the air quality impacts on the industries affected by this rule. Following 

proposal, we revised the standards for room heaters and central heaters based on public 

comments. Table 6 is a summary of the revised estimated annual average emissions 

reductions over years 2015 through 2020 resulting from implementing the final NSPS 

compared to baseline conditions (for the years analyzed in the final RIA). As in the 

proposal, we developed emission factors for each appliance type and then applied those 

emission factors to shipment data for each of the appliance types subject to the final 

NSPS.16 We developed the emission factors using the EPA Residential Wood 

Combustion (RWC) emission estimation tool,17 which is a Microsoft Access database 

that compiles nationwide RWC emissions using county-level, process-specific data and 

calculations. The compilation of such data is a large, important, continually improving 

effort by the EPA and the states to ensure that we and the states have access to the best 

 

16 Memo to USEPA from EC/R, Inc. Estimated Emissions from Wood Heaters. January 

2015.

17 Emission factors are based on EPA's Residential Wood Combustion Tool version 4.1 

with updates from the 2012 EPA report (Gullett et al. Environmental, Energy Market, and 

Health Characterization of Wood-Fired Hydronic Heater, Final Report, June 2012).
Page 84 of 326

information available. For the final rule, we used the updated version of the tool. The 

updated tool includes the results of a peer-reviewed emission testing study of hydronic 

heaters conducted by the EPA Office of Research and Development and the New York 

State Energy Research and Development Agency. (The study was added to the docket 

prior to proposal but the tool was not updated until after proposal.) The results of that 

study show much higher emissions for hydronic heaters at baseline than we estimated at 

proposal. We have used the updated emission factors because they are based on the best 

available scientific information. We summed the estimated nationwide number of 

appliances and the estimated total tons of wood burned for each of the relevant product 

categories in the inventory and then made some adjustments/assumptions to the baseline 

RWC inventory to reflect emission characteristics specific to new units. As described 

below, to avoid any potential for overstating baseline emissions, we went a step further 

and assumed that all new shipments will meet the current State of Washington 

Department of Ecology limits, which are approximately 40 percent less than the 1988 

NSPS.

Single burn rate stoves are not included in the RWC database as separate 

identifiable units. For our analysis, we used the same baseline emission factor as 

freestanding non-certified wood stoves. We used the average tons burned per appliance 

factor as representative of these stoves as well. 

After calculating a baseline average emission rate/appliance (or “emission 

inventory category”), we multiplied the total tons of wood burned for the appliance by 

the RWC emission factor (adjusted as appropriate) to calculate the total tons of PM2.5

emissions. We divided this value by the number of appliances in the category to calculate 
Page 85 of 326

the baseline average PM2.5 emissions per individual appliance. The next step was to 

develop emission factors representing the final NSPS. The timing of the NSPS emission 

limits used in this analysis matches the phased-in compliance dates.

For the subpart AAA analysis, we used HPBA data from their 2010 analysis that 

indicated that at least 90 percent (130 out of 145 catalytic, non-catalytic and pellet stoves 

combined) already meet the Step 1 PM emission limit. Manufacturers are expected to 

focus on existing models that already meet the Washington State DOE limits in order to 

comply with the Step 1 PM emission limit. Furthermore, certification data18 indicate that 

26 percent of non-catalytic and catalytic stoves combined and 70 percent of pellet stoves 

already meet the Step 2 PM emission limit. For our analysis, we used 26 percent of 

adjustable burn rate stoves and 70 percent of pellet stoves for the percentages that can 

already meet the Step 2 PM emission limit without intensive R&D efforts. Although 

previously unregulated and a less developed technology than adjustable burn rate stoves, 

single burn rate stove designs have been undergoing R&D in anticipation of the proposed 

NSPS and cleaner designs are in progress.

For the subpart QQQQ analysis for hydronic heaters, we note that the Step 1 PM 

emission limit is the EPA “Phase 2” voluntary program lb/mmBtu weighted average 

emission limit is already met by 50 hydronic heater models built by U.S. manufacturers 

participating in the voluntary program. We also note that 19 additional qualification tests 

have been recently submitted to EPA and, if valid, all 19 will be added as Phase 2 

qualified models and Step 1 NSPS certified models. The NSPS Step 2 PM emission limit 

is already met by 9 hydronic heater models built by U.S. manufacturers participating in 

 

18 Memo to USEPA from EC/R, Inc. Derivation of wood heater model percentages 

meeting Step 2 standards. November 2014.
Page 86 of 326

the voluntary program, as well as over 100 European models per test method EN 303-05 

and over 20 pellet boilers (U.S. and European) that have been qualified in the RHNY 

program. Data indicate that at least 18 percent of current hydronic heater model designs 

can meet the Step 2 emission limit without intensive R&D efforts.

For the subpart QQQQ analysis for forced-air furnaces, we note that the Step 1 

PM emission limit is based on test data from certifications under the Canadian standard 

B415.1-10 (circa 2010) and conversations with industry regarding cleaner forced-air

furnace models currently being tested in R&D. As discussed earlier in this preamble, 

forced-air furnace designs able to meet the Step 2 limit are based on technology 

transferred from hydronic heater designs and/or wood stove designs.

Next we used data in the Frost & Sullivan Market (F&S) report19 on 2008 

shipments by product category, and F&S revenue forecasts which incorporated the weak 

economy in years 2009 and 2010, to calculate the reduced number of shipments in years 

2009 and 2010. Forced-air furnaces were outside the scope of the F&S report. Instead, we 

used manufacturer estimates of total industry sales in 2008 and applied the F&S market 

factors to estimate shipments through 2010. The F&S wood stove numbers included both 

certified and non-certified stoves, so we estimated numbers of non-certified stove 

shipments out of the total reported wood stove category (i.e., 40,000 single burn rate 

stoves shipped in 2008). These shipments were deleted from the total wood stove 

category shipments. We expanded the 2008 single burn rate estimate using the F&S 

factors. 

 

19 Market Research and Report on North American Residential Wood Heaters, Fireplaces, 

and Hearth Heating Products Market. Prepared by Frost & Sullivan. April 26, 2010. P. 

31-32.
Page 87 of 326

For years 2011 through 2029, estimated shipments are generally based on a 

forecasted revenue growth rate of 2.0 percent, in keeping with the average annual growth 

in real U.S. GDP predicted by the Conference Board.20 Historically wood heater 

shipments have most closely corresponded to GDP, housing starts, and price of wood 

relative to natural gas. The overall trend in the projection is reasonable in the absence of 

additional specific shipment projections. We did not change the relative percentages of 

one type of residential wood heater versus other types of residential wood heaters over 

this time period. The only exceptions to the use of a 2.0 percent U.S. GDP-based growth 

rate are for years 2012 and 2018, in which we used industry estimates for hydronic heater 

and wood stove shipments, respectively. For year 2012, an HPBA consultant estimated 

there were 13,100 baseline hydronic heater sales.21 For year 2018, the same HPBA 

consultant projected there to be 100,000 wood stove sales.22 We adjusted our estimated 

shipment data accordingly. 

Our cost effectiveness analysis (CE) is based on industry data that show that a 

given model design will often be sold for approximately 10 years before being redesigned 

(a 10-year “model design lifespan”) and that each individual stove will be used for 20 

years before it is replaced in a residence (a 20-year “use/emitting appliance lifespan”). 

These time periods were used to best characterize the actual model design and use 

 

20 Global Economic Outlook 2014, projections prepared by the Conference Board, May 

2014 update; http://www.conference-board.org/data/globaloutlook.cfm.

21 Cost-Effectiveness Analysis of Alternative Hydronic Heater New Source Performance 

Standards, prepared for the Hearth, Patio, and Barbecue Association by NERA Economic 

Consulting, May 2014. (Attachment 3 of HPBA’s comment to the Docket EPA-HQOAR-2009-0734).

22 Cost-Effectiveness Analysis of Alternative Woodstove New Source Performance 

Standards, prepared for the HPBA by NERA Economic Consulting, May 2014. 

(Attachment 2 of HPBA’s comment to Docket EPA-HQ-OAR-2009-0734).
Page 88 of 326

lifespans. For proposal, we used a 20-year model design lifespan because many models 

developed for the 1988 NSPS are still being sold (after 25 years), with many “new” 

models retaining the same internal working parts with merely exterior cosmetic changes. 

In response to comments on the proposed rule23, however, in which some industry 

representatives commented that a shorter model lifespan is more typical, and provided 

data for models for several manufacturers, we reduced the model design lifespan to 10 

years for this analysis. Regarding the emitting lifespan of the appliance, most wood 

heaters in consumer homes emit for at least 20 years and often much longer. Therefore, 

our CE analysis tracks shipments through year 2029 (using a 10-year design life for a 

model meeting the Step 2 emission limit in year 2020) and emissions through year 2048 

(using a 20-year emitting life for an appliance shipped in year 2029).

Table 6 is a summary of the average emissions reductions over years 2015 

through 2020 resulting from implementing the NSPS compared to baseline conditions 

(for the years analyzed in the RIA).

 

23 Comments on the proposed NSPS are available electronically through 

http://www.regulations.gov by searching Docket IDs EPA-HQ-OAR-2009-0734.
Page 89 of 326

Table 6. Estimated Annual Average (2015-2020) Air Quality Impacts24

Appliance Type

PM2.5 (tons) VOC (tons) CO (tons)

Baseline

Revised 

NSPS

Emission 

Reduction Baseline

Revised 

NSPS

Emission 

Reduction Baseline

Revised 

NSPS

Emission 

Reduction

Wood Heaters 422 388 34 601 554 47 6,048 5,528 520

Single Burn 

Rate Heaters 922 238 684 1,597 326 1,271 6,954 3,830 3,124

Pellet 

Heaters/Stoves 59 53 6 1 1 0 307 277 30

Furnace: 

Indoor, Cord 

Wood 6,984 2,944 4,040 7,355 3,101 4,254 39,285 16,561 22,724

Hydronic 

Heating 

Systems 3,844 338 3,506 4,048 356 3,692 21,623 1,902 19,721

Total 12,231 3,962 8,269 13,602 4,337 9,265 74,218 28,099 46,119

Note: This table only includes the emissions during the first year of the life of each wood heater. That is, this table does not 

include the emissions that continue for the duration of the lifetime of each appliance’s use, typically greater than 20 years. The 

EPA acknowledges that this is an underestimate of the actual total emission impacts but this table is provided to allow 

comparisons on a first year basis.

Minor discrepancies are due to rounding.

 

24 Memo to USEPA from EC/R, Inc. Estimated Emissions from Wood Heaters. January 2015.
Page 90 of 326

B. What are the Benefits?

Emission reductions associated with the requirements of this rule will generate 

substantial health benefits by reducing emissions of PM2.5, HAPs, as well as criteria 

pollutants and their precursors, including CO and VOC. VOC are precursors to PM2.5 and 

ozone. For this rule, we were only able to quantify the monetized health co-benefits 

associated with reduced exposure from directly emitted PM2.5. Our benefits reflect the 

average of annual PM2.5 emission reductions occurring between 2015 and 2020 

(inclusive). We estimate the monetized PM2.5 -related health benefits of the residential 

wood heaters NSPS in the 2015-2020 timeframe to be $3.4 billion to $7.6 billion (2013 

dollars) at a 3-percent discount rate and $3.1 billion to $6.9 billion (2013 dollars) at a 7-

percent discount rate. (These estimates are greater than the estimates at proposal because 

the emission reduction estimates are greater, as discussed in section VI.A of this 

preamble and the RIA.) Using alternate relationships between PM2.5 and premature 

mortality supplied by experts, higher and lower benefits estimates are plausible, but most 

of the expert-based estimates fall between these two estimates.25 A summary of the 

emission reduction and monetized benefits estimates for this rule at discount rates of 3 

percent and 7 percent is in Table 7 of this preamble.

Table 7. Summary of Monetized PM2.5-related Health Benefits for Proposed 

Residential Wood Heaters NSPS in 2015-2020 Timeframe 

(millions of 2013 dollars)a, b, c

Pollutant

Estimated Emission 

Reductions

(tpy)

Total Monetized 

Benefits

(3% Discount Rate)

Total Monetized Benefits

(7% Discount Rate)

 

25 Roman, et al, 2008. “Expert Judgment Assessment of the Mortality Impact of Changes 

in Ambient Fine Particulate Matter in the U.S.,” Environ. Sci. Technol., 42, 7, 2268 –

2274.
Page 91 of 326

Directly 

emitted 

PM2.5

8,269 $3,400 to $7,600 $3,100 to $6,900

PM2.5Precursors

VOC 9,265 -- --

a All estimates are for the 2015-2020 timeframe (inclusive) and are rounded to two 

significant figures so numbers may not sum across rows. The total monetized benefits 

reflect the human health benefits associated with reducing exposure to PM2.5 through 

reductions of PM2.5 precursors, such as NOX, and directly emitted PM2.5. It is important to 

note that the monetized benefits do not include reduced health effects from exposure to 

HAP, direct exposure to NO2, exposure to ozone, VOC, ecosystem effects, effects from 

black carbon or visibility impairment. 

b PM benefits are shown as a range from Krewski, et al. (2009) to Lepeule, et al. (2012).

c These models assume that all fine particles, regardless of their chemical composition, 

are equally potent in causing premature mortality because the scientific evidence is not 

yet sufficient to allow differentiation of effects estimates by particle type.

These benefit estimates represent the monetized human health benefits for 

populations exposed to less PM2.5 from emission limits established to reduce air 

pollutants in order to meet this rule. Due to analytical limitations, it was not possible to 

conduct air quality modeling for this rule. Instead, we used a “benefit-per-ton” approach 

to estimate the benefits of this rulemaking. To create the benefit-per-ton estimates, this 

approach uses a model to convert emissions of PM2.5 precursors into changes in ambient 

PM2.5 levels and another model to estimate the changes in human health associated with 

that change in air quality, which are then divided by the emissions in specific sectors. 

These benefit-per-ton estimates were derived using the approach published in Fann, et al. 

(2012),26 but they have since been updated to reflect these studies and population data in 

 

26 Fann, N., K.R. Baker, and C.M. Fulcher. 2012. “Characterizing the PM2.5-related 

health benefits of emission reductions for 17 industrial, area and mobile emission sectors 

across the U.S.” Environment International 49 41–151.
Page 92 of 326

the 2012 PM NAAQS RIA.27 Specifically, we multiplied the benefit-per-ton estimates 

from the “Residential Wood Heaters” category by the corresponding emission 

reductions.28 All national-average benefit-per-ton estimates reflect the geographic 

distribution of the modeled air quality. The air quality modeling may not reflect the local 

variability in population density, meteorology, exposure, baseline health incidence rates, 

or other local factors for any specific location. More information regarding the derivation 

of the benefit-per-ton estimates for this category is available in the technical support 

document, which is referenced in footnote 26 and is available in the docket. 

These models assume that all fine particles, regardless of their chemical 

composition, are equally potent in causing premature mortality because the scientific 

evidence is not yet sufficient to allow differentiation of effects estimates by particle type. 

Even though we assume that all fine particles have equivalent health effects, the benefitper-ton estimates vary between precursors depending on the location and magnitude of 

their impact on PM2.5 levels, which drive population exposure. 

It is important to note that the magnitude of the PM2.5 benefits is largely driven by 

the concentration response function for premature mortality. We cite two key empirical

 

27 U.S. Environmental Protection Agency (U.S. EPA). Regulatory Impact Analysis for the 

Final Revisions to the National Ambient Air Quality Standards for Particulate Matter. 

EPA-452/R-12-003. Office of Air Quality Planning and Standards, Health and 

Environmental Impacts Division. December 2012. Available at 

http://www.epa.gov/pm/2012/finalria.pdf.

28 U.S. Environmental Protection Agency. Technical support document: Estimating the 

benefit per ton of reducing PM2.5 precursors from 17 sectors. Research Triangle Park, 

NC. January 2013.
Page 93 of 326

studies, one based on the American Cancer Society cohort study29 and the extended Six 

Cities cohort study.30 In the RIA for this rule, which is available in the docket, we also 

include benefits estimates derived from expert judgments (Roman et al, 2008) as a 

characterization of uncertainty regarding the PM2.5-mortality relationship. 

Considering a substantial body of published scientific literature, reflecting 

thousands of epidemiology, toxicology, and clinical studies, the EPA’s Integrated 

Science Assessment for Particulate Matter31 documents the association between elevated 

PM2.5 concentrations and adverse health effects, including increased premature mortality. 

This assessment, which was reviewed twice by the EPA’s independent Clean Air 

Scientific Advisory Committee, concluded that the scientific literature consistently finds 

that a no-threshold model most adequately portrays the PM-mortality concentrationresponse relationship. Therefore, in this analysis, the EPA assumes that the health impact 

function for fine particles is without a threshold. 

In general, we are more confident in the magnitude of the risks we estimate from 

simulated PM2.5 concentrations that coincide with the bulk of the observed PM 

concentrations in the epidemiological studies that are used to estimate the benefits. 

Likewise, we are less confident in the risk we estimate from simulated PM2.5

 

29 Krewski, C.A., III, R.T. Burnett, M.J. Thun, E.E. Calle, D. Krewski, K. Ito, and G.D. 

Thurston. 2002. “Lung Cancer, Cardiopulmonary Mortality, and Long-term Exposure to 

Fine Particulate Air Pollution.” Journal of the American Medical Association 287:1132-

1141.

30 Lepeule J, Laden F, Dockery D, Schwartz J 2012. “Chronic Exposure to Fine Particles 

and Mortality: An Extended Follow-Up of the Harvard Six Cities Study from 1974 to 

2009.” Environ Health Perspect. Jul;120(7):965-70.

31 U.S. Environmental Protection Agency (U.S. EPA). 2009. Integrated Science 

Assessment for Particulate Matter (Final Report). EPA-600-R-08-139F. National Center 

for Environmental Assessment – RTP Division. December. Available on the Internet at 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=216546.
Page 94 of 326

concentrations that fall below the bulk of the observed data in these studies. 

Concentration benchmark analyses [e.g., lowest measured level (LML) or one standard 

deviation below the mean of the air quality data in the study] allow readers to determine 

the portion of population exposed to annual mean PM2.5 levels at or above different 

concentrations, which provides some insight into the level of uncertainty in the estimated 

PM2.5 mortality benefits. There are uncertainties inherent in identifying any particular 

point at which our confidence in reported associations becomes appreciably less, and the 

scientific evidence provides no clear dividing line. However, the EPA does not view 

these concentration benchmarks as a concentration threshold below which we would not 

quantify health benefits of air quality improvements. 

For this analysis, policy-specific air quality data are not available. Thus, we are 

unable to estimate the percentage of premature mortality associated with this specific 

rule’s emission reductions at each PM2.5 level. As a surrogate measure of mortality 

impacts, we provide the percentage of the population exposed at each PM2.5 level using 

the source apportionment modeling used to calculate the benefit-per-ton estimates for this 

sector. Using the Krewski, et al, (2009) study, 93 percent of the population is exposed to 

annual mean PM2.5 levels at or above the LML of 5.8 μg/m3. Using the Lepeule, et al,

(2012) study, 67 percent of the population is exposed above the LML of 8 μg/m3. It is 

important to note that baseline exposure is only one parameter in the health impact 

function, along with baseline incidence rates, population, and change in air quality. 

Therefore, caution is warranted when interpreting the LML assessment for this rule. 

Every benefit analysis examining the potential effects of a change in 

environmental protection requirements is limited, to some extent, by data gaps, model 
Page 95 of 326

capabilities (such as geographic coverage) and uncertainties in the underlying scientific 

and economic studies used to configure the benefit and cost models. Despite these 

uncertainties, the benefit analysis for this rule provides a reasonable indication of the 

expected health benefits of the rulemaking under a set of reasonable estimations. 

One should note that the monetized benefits estimates provided above do not 

include benefits from several important benefit categories, including exposure to HAP, 

VOC and ozone exposure, as well as ecosystem effects, visibility impairment and 

greenhouse gas impacts. Although we do not have sufficient information or modeling 

available to provide monetized estimates for these benefits in this rule, we include a 

qualitative assessment of these unquantified benefits in the RIA32 for this final rule.

For more information on the benefits analysis, please refer to the RIA for this 

rule, which is available in the docket.

C. What are the Cost Impacts? 

In analyzing the potential cost impacts of the NSPS, we considered two types of 

impacts. The first was the impact to the manufacturer to comply with the proposed 

standards. The second was the increase in price of the affected unit. In both of these 

cases, we considered the same input variables: research and development (R&D) cost to 

develop and certify complying model lines, certification costs (where these are separate 

from R&D), reporting and recordkeeping costs, numbers of shipments of each appliance 

category (modified, from Frost & Sullivan report), number of manufacturers, and number 

of models per manufacturer. This section of the preamble contains a summary of these 

 

32 RIA for the Final Residential Wood Heaters NSPS.
Page 96 of 326

costs. For more detailed information, see the manufacturer cost impact memo33 and unit 

cost memo34 in the docket. Unless otherwise specified, all costs are in 2013 dollars.

As discussed in detail in section IV.C, we reviewed information provided by 

HPBA and manufacturers. Based on this information, we estimated35 average costs to 

develop a new model line. The estimates of the cost of R&D are crucial to our estimates 

of overall costs and economic impacts and greatly influence our decisions on BSER and 

implementation lead times. We annualized the R&D costs over 6 years, applied the NSPS 

implementation assumptions, and estimated the average manufacturing cost per model 

line per manufacturer.

The estimate of the number of model types was derived from information 

provided by HPBA, individual manufacturers, and Internet searches of product offerings. 

For numbers of manufacturers, we started with HPBA data and modified the dataset 

based on Internet searches of manufacturers of the major appliance types. Table 8 is a 

summary of the nationwide average annual NSPS-related cost increases to manufacturers. 

The average annual cost increases are presented over the 2015 to 2020 period consistent 

with the years analyzed in the RIA,36 but were also analyzed over the 2015 to 2029 

period. The 2015 to 2029 period encompasses the 2015 NSPS compliance year through 

 

33 Memo to USEPA from EC/R, Inc. Residential Heater Manufacturer Cost Impacts. 

January 2015.

34 Memo to USEPA from EC/R, Inc. Unit Cost Estimates of Residential Wood Heating 

Appliances. January 2015.

35 In developing average R&D costs, we used the highest industry R&D estimates 

supplied for cost components we deemed attributable to the NSPS, in order to avoid 

under-estimating potential costs per model line. We also assumed no model consolidation 

to avoid understating the number of model lines that would undergo R&D nationwide.

36 RIA for the Final Residential Wood Heaters NSPS.
Page 97 of 326

the life span of models designed to meet the NSPS, as explained further below and in our 

background analyses.37

Table 8. Summary of Nationwide Average Annual Cost Increases (2013$)

Appliance Type 2015-2020 Period

Wood Heaters $3,020,000

Single Burn Rate Heaters $870,000

Pellet Heaters/Stoves $1,520,000

Forced-Air Furnaces $15,360,000

Hydronic Heating 

Systems $24,880,000

Total Average Annual 

Cost $45,660,000

To develop estimates of potential unit cost increases, we used major variables 

including the estimated number of units shipped per year, the costs to develop new 

models, baseline costs of models, and the schedule by which the revised NSPS would be 

implemented. Both the number of shipped units and the baseline costs of models 

(manufacturers’ cost not retail price) were initially based on data from the Frost & 

Sullivan report with modifications to address additional appliances or subsets of 

appliances and industry comments as discussed in our background analyses.38 We also 

estimated the potential additional manufacturing costs to make NSPS complying models. 

These expenses result from the use of more expensive structural materials, components to 

enhance good combustion, etc. We estimated the following additional manufacturing 

costs per unit based on appliance type:

 

37 Memo to USEPA from EC/R, Inc. Residential Heater Cost Effectiveness Analysis. 

January 2015.

38 Memo to USEPA from EC/R, Inc. Unit Cost Estimates of Residential Wood Heating 

Appliances. January 2015.
Page 98 of 326

 Certified wood stoves and pellet stoves represent a well-developed technology 

and we could not identify price differences between models with lower emission levels 

compared to models with higher emission levels. Some stoves with lower emission sell 

for less than some stoves with higher emissions and vice versa. Therefore, we have 

assumed no additional manufacturing costs.

 One manufacturer estimated that it will cost an average of $100 more to 

manufacture a lower emitting single burn rate product (exclusive of recovering R&D 

cost), which we updated to 2013 ($), approximately $110.39

 We have limited information that indicates the cost to produce a forced-air 

furnace that complies with a Step 1 emission limit is approximately 75 percent more, or 

$1,700 (exclusive of recovering R&D cost).40

 As can be seen in hydronic heater market survey results, the prices of qualified 

model hydronic heaters range from $6,995 to $15,395, with the average retail price of 

$10,193. We adjusted this value to exclude the 25 percent retail markup, resulting in a 

manufacturers’ cost estimate of $8,154.41 We estimated an approximate increase of 

$3,200 to manufacture a qualified unit compared to an unqualified unit.

Our next step was to develop the following incremental cost formula: Cost of 

amortized R&D multiplied by number of models divided by number of units shipped per 

year equals the incremental cost of developing a new unit, spread over the number of 

units expected to be sold during a given year in the 6-year model development period. In 

 

39 NSPS Review and Comments. Confidential Business Information. September 2010.

40 Confidential Business Information.

41 Cost-Effectiveness Analysis of Alternative Hydronic Heater New Source Performance 

Standards. Prepared by NERA Consulting for the Hearth, Patio and Barbecue 

Association. May 2014. p. 10.
Page 99 of 326

developing this calculation, we included the concept that the R&D costs per model line 

are recovered in the sales price of future models, which means that the more units that are 

sold, the lower the incremental cost per unit. For our unit cost analysis, we used a flat rate 

in shipments – that is, future shipments over the 6-year model development period would 

be equal to the shipments estimated in the first year of the 6-year model development 

period (2015). The flat rate was used because we had no basis for concluding that sales of 

a given model line would increase or decrease over time due to market competition with 

other wood heaters or non-wood heaters, changes in consumer demand, changes in the 

relative price for that model compared to other models or any other factors. Where there 

are additional manufacturing costs as discussed above, we added these to the unit cost 

number. Table 9 shows the change in cost to develop and manufacture a stove from 

baseline (before the NSPS revisions) to after the NSPS revisions are implemented. The 

economic impacts of these costs are discussed in section C, “What are the economic 

impacts?” More information on both the costs and economic impacts is available in the 

RIA.

Table 9. Summary of Unit Costs (Appliance prices in 2013 $)

Appliance Type

Cost At 

Baseline 

(2014)

Total Cost 

During NSPS 

model 

development 

(2015-2020)

Incremental

Cost 

Increase (to 

recover 

amortized 

costs)

Certified Wood Heaters $1,259 $1,307 $48

Single Burn Rate Heaters $271 $410 $139

Pellet Heaters/Stoves $1,384 $1,430 $46

Forced-Air Furnaces $974 $3,225 $2,251

Hydronic Heating Systems $4,923 $10,287 $5,364

More information is available in the RIA.
Page 100 of 326

D. What are the Economic Impacts?

The economic impacts of the rule are estimated using industry-level estimates of 

annualized compliance cost to value of shipments (receipts) for affected industries. In this 

case, cost-to-receipts ratios approximate the maximum price increase needed for a 

producer to fully recover the annualized compliance costs associated with a regulation. 

Essentially, the revenues to producers will likely fully cover the annualized compliance 

cost incurred by producers at this maximum price increase. Any price increase above the 

cost-to-receipts ratio provides revenues that exceed the compliance costs. These industry 

level cost-to-receipts ratios can be interpreted as an average impact on potentially 

affected firms in these industries. Cost-to-receipts ratios for the affected product types 

range from 1.1 percent for pellet heaters/stoves to up to 17.1 percent for hydronic heaters.

More information on how these impacts are estimated can be found in Chapters 5 and 6 

of the RIA.

In estimating the net benefits of regulation, the appropriate cost measure is “social 

costs.” Social costs represent the welfare costs of the rule to society and fully represent 

the cost impacts regardless of whether they are ultimately borne by manufacturers or 

consumers. Social costs are best approximated by the compliance costs estimated for this 

rule. Thus, the annualized social costs are best estimated to be $45.7 million, based on the 

estimate of costs to manufacturers and assuming no cost pass-through to consumers. 

Several comments noted that these potential price increases can often be offset by the 

homeowner in one or two heating seasons by the reduced cost of fuel due to the increased 

heating efficiencies. More information on how these social costs are estimated can be 

found in Chapter 5 of the RIA.
Page 101 of 326

E. What Are the Non-air Quality Health and Energy Impacts?

These NSPS are anticipated to have no impacts or only negligible impacts on 

water quality or quantity, waste disposal, radiation or noise. To the extent new NSPS 

models are more efficient, that would lead to reduced wood consumption, thereby saving 

timber and preserving woodlands and vegetation for aesthetics, erosion control, carbon 

sequestration, and ecological needs.

It is difficult to determine the precise energy impacts that might result from this 

rule. On the one hand, to the extent that the NSPS wood-fueled appliance is more 

efficient, energy outputs per mass of wood fuel consumed will rise. However, woodfueled appliances compete with other biomass forms as well as more traditional oil, 

electricity, and natural gas. Robust data are not available for us to be able to determine 

the potential for consumers to choose other types of fuels and their associated appliances 

if the consumer costs of wood-fueled appliances increase and at what level that increase 

would drive consumer choice. Similarly, robust data are not available for us to determine 

the degree to which better information on the energy efficiency of the NSPS appliances 

will encourage consumers to choose new wood-fueled appliances over other new 

appliances.

VII. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 

13563: Improving Regulation and Regulatory Review

This action is an economically significant regulatory action that was submitted to 

the Office of Management and Budget (OMB) for review. Any changes made in response 

to OMB recommendations have been documented in the docket. The EPA prepared an 

analysis of the potential costs and benefits associated with this action. This analysis, 
Page 102 of 326

“Regulatory Impact Analysis (RIA) for Residential Wood Heaters NSPS Revision, Final 

Report” (EPA-452/R-15-001), is available in the docket.

A summary of the monetized benefits and net benefits for the final rule at 

discount rates of 3 percent and 7 percent is in Table 1 of this preamble, and a more 

detailed discussion of the benefits is found in section IV.B of this preamble. For more 

information on the benefits analysis, please refer to the RIA for this rulemaking, which is 

available in the docket. For more information on the cost analysis, please refer to the RIA 

or cost memoranda prepared for this rulemaking, all of which is available in the docket.

B. Paperwork Reduction Act (PRA)

The information collection requirements in the rule have been submitted for 

approval to OMB under the PRA. The Information Collection Request (ICR) documents 

that the EPA prepared for each subpart have been assigned the EPA ICR number 1176.12 

for subpart AAA and ICR number 2442.02 for subpart QQQQ. You can find a copy of 

the ICR documents in the docket for this rule, and they are briefly summarized here. The 

new information collection requirements are not enforceable until OMB approves them. 

This final rule will require manufacturers of new residential wood heating devices 

to submit applications for certification of model lines, to submit results of emissions tests 

conducted to demonstrate that the model lines would comply with the emission limits and 

produce certified units according to a quality control plan approved by an independent 

certifying body. Manufacturers must submit a notification of the initial test and biennial 

reports that each certified model line remains unchanged. They must also maintain 

records of all certification data, maintain results of quality assurance program inspections 

and emissions test data, and seal and store the tested appliance. 
Page 103 of 326

Consistent with the current ICR for subpart AAA, we have included costs to 

manufacture and apply permanent labels on each applicable unit prior to sale. These 

labels provide important compliance information to enforcement officials and important 

information to consumers for purchasing appliances. The amended NSPS allows 

(voluntary) use of EPA temporary labels for the cleanest heaters in order to provide 

consumers the ability to select wood heaters that meet or exceed the Step 2 standards 

prior to the 2020 compliance date. This voluntary temporary label option ends upon the 

2020 compliance date. Furthermore, the amended NSPS also allows (voluntary) use of 

temporary EPA labels to indicate wood heaters that meet Step 2 based on cord wood 

instead of crib wood, allowing consumers to select heaters better tuned to in-home 

performance. The cost of the voluntary temporary labels are not included because they 

are not required.

Test laboratories that want to conduct NSPS certification testing will need to 

apply for approval, conduct proficiency testing and report the results of all such testing. 

The approved laboratories must maintain records of all certification tests, proficiency 

tests and compliance audit test data.

The required notifications are used to inform the agency when a new model line is 

expected to be tested. The EPA and states may then observe the testing, if desired. 

Emissions test reports are needed as these are the agency’s record of a model line’s initial 

capability to comply with the emission limit, and serve as a record of the operating 

conditions under which compliance was achieved. All information submitted to the EPA 

for which a claim of confidentiality is made (e.g., design drawings) will be safeguarded 
Page 104 of 326

according to the EPA regulations set forth in 40 CFR 2.201 et seq., Chapter 1, Part 2, 

Subpart B – Confidentiality of Business Information.

Adequate recordkeeping and reporting are necessary to ensure compliance with 

these standards as required by the CAA. The information collected from recordkeeping 

and reporting requirements is also used for prioritizing inspections and is of sufficient 

quality to be used as evidence in court. We have reviewed all the current requirements 

and have removed the portions of the recordkeeping that are not necessary.

The EPA considered how to minimize the potential ICR burdens and has 

incorporated several features that make a major paperwork reduction impact. For 

example, the rule allows one representative heater to be tested for a model line rather than 

requiring every heater to be tested. The revised subpart AAA itself “deems” automatic 

EPA certification of heaters that have EPA certifications under the 1988 NSPS that show 

that they would meet the Step 1 emission limits until Step 2. That is, no additional 

certification is required until Step 2. Also, the new subpart QQQQ deems automatic EPA 

NSPS Step 1 certification for hydronic heaters with valid EPA Phase 2 qualifications 

under the EPA Hydronic Heater Partnership Agreement of October 12, 2011 or hydronic 

heaters or forced-air furnaces certified by the NYSDEC that show compliance with the 

Step 1 emission levels. That is, no additional certification is required until Step 2. Also, 

residential pellet hydronic heaters/boilers that have been qualified under the Renewable 

Heat New York (RHNY) program will be automatically deemed EPA certified to meet 

the NSPS Step 1 and no additional certification is required until Step 2 provided that they 

comply with the RHNY requirements for installation and operation with adequate 

thermal storage.
Page 105 of 326

Respondents/affected entities: Manufacturers of new residential wood heaters and 

laboratories that conduct or plan to conduct wood heater certification tests

Respondent’s obligation to respond: Mandatory under section 111 of the CAA

Estimated number of respondents: 72 respondents under subpart AAA (66 

manufacturers and 6 testing laboratories); 41 respondents under subpart QQQQ (37 

manufacturers and 4 testing laboratories)

Frequency of responses: once per model line, annually, biennially, variable and/or 

infrequent

Total estimated burden: 2,947 labor hours (per year) under subpart AAA; 2,337

labor hours (per year) under subpart QQQQ. Burden is defined at 5 CFR 1320.3(b).

Total estimated cost: $1,716,990 (per year) under subpart AAA, includes 

$1,466,440 annualized capital and operation & maintenance costs; $3,383,100 (per year) 

under subpart QQQQ, includes $3,191,200 annualized capital and operation & 

maintenance costs

An agency may not conduct or sponsor, and a person is not required to respond to, 

a collection of information unless it displays a currently valid OMB control number. The 

OMB control numbers for the EPA’s regulations in 40 CFR are listed in 40 CFR part 9. 

When OMB approves this ICR, the agency will announce that approval in the Federal 

Register and publish a technical amendment to 40 CFR part 9 to display the OMB control 

number for the approved information collection activities contained in this final rule.

C. Regulatory Flexibility Act (RFA)

Pursuant to sections 603 and 609(b) of the RFA, the EPA prepared an initial 

regulatory flexibility analysis (IRFA) for the proposed rule and convened a Small 
Page 106 of 326

Business Advocacy Review (SBAR) Panel to obtain advice and recommendations from 

small entity representatives that potentially would be subject to the rule's requirements. 

Summaries of the IRFA and Panel recommendations are presented in the proposed rule at

79 FR 6329.

As required by section 604 of the RFA, the EPA prepared a final regulatory 

flexibility analysis (FRFA) for this action. The FRFA addresses the issues raised by 

public comments on the IRFA for the proposed rule. The complete FRFA is available for 

review in the docket and is summarized here.

 Reason Why Action Is Being Considered. As discussed earlier in this preamble, 

this final rule was developed following CAA section 111(b)(1)(B) review of the existing 

residential wood heater NSPS, and because emissions from residential wood heaters can 

be a significant source of air pollution, and thus adverse health effects, in some areas. 

 Statement of Objectives and Legal Basis of Rule. As discussed earlier in this 

preamble, the EPA is amending Standards of Performance for New Residential Wood 

Heaters and adding one new subpart, Standards of Performance for New Residential 

Hydronic Heaters and Forced-Air Furnaces. This final rule achieves several objectives, 

including applying updated emission limits that reflect BSER; improving coverage of the 

broad suite of residential wood heaters; improving the test methods; and streamlining the 

certification process. This final rule does not include any requirements on heaters solely 

fired by coal, gas or oil. This final rule does not establish new emissions limits for 

existing heaters. This rule was developed under the authority of CAA section 111.
Page 107 of 326

 Response to Any Comments to the Proposed Rule Filed by the Chief Counsel for 

Advocacy of the SBA. The SBA’s Chief Counsel for Advocacy did not file any 

comments to the proposed rule.

 Description and Estimate of the Number of Small Entities. As discussed earlier in 

this preamble, small entities that the EPA anticipates being affected by this rule will

include almost all manufacturers of residential wood heaters. We estimate that roughly

250–300 U.S. companies manufacture residential wood heaters. Approximately 90 

percent of these manufacturers meet the SBA small-entity definition of having fewer than 

500 employees.

 Description of reporting, recordkeeping and other compliance requirements. The 

reporting and recordkeeping requirements are described in the section immediately above 

(B. Paperwork Reduction Act). As discussed there, the information collection 

requirements (ICR), including reporting and recordkeeping, in this rule have been 

submitted for approval to OMB under the Paperwork Reduction Act, 44 U.S.C. 3501 et 

seq. For subpart AAA, we estimated the potential annual burden averaged over the first 3 

years of the ICR to be a total of 2,947 labor hours per year at a total labor cost of 

$250,551 per year and an average annual labor burden per response of 12 hours. For 

subpart QQQQ, we estimated 2,337 labor hours per year at a total labor cost of $191,904

per year and an average annual labor burden per response of 12 hours.

 Description of other compliance requirements. As described earlier in this 

preamble, this rule will apply updated emission limits that reflect the current best systems 

of emission reduction (BSER) and improve the coverage of the expanded variety of types 

of residential wood heaters. We estimate the NSPS’s total annualized average nationwide 
Page 108 of 326

costs will be $45.7 million (2013$) over the 2015 through 2020 period. The economic 

impacts for industries affected by this rule over this same period range from 1.1 percent 

for manufacture of pellet stove models to as much as 17.1 percent compliance cost-tosales estimate for manufacture of hydronic heater models. These impacts do not presume 

any pass-through of impacts to consumers. With pass-through to consumers, these impact 

estimates to manufacturers will decline proportionate to the degree of pass-through. We 

estimate that small entities will have annualized costs of greater than 1 percent of their 

sales in all affected industries, and NAICS 442299 with receipts less than $10 million. 

Those establishments in NAICS 332510, 333414 and 423720 with cost-to-receipt ratios 

higher than 1 percent account for 90 percent of small entities affected in these industries. 

Establishments in NAICS 442299 with cost-to-receipt ratios higher than 1 percent 

account for 99 percent of small entities affected in these industries.

 Relevant federal rules that may overlap or conflict with this rule. There are no 

other relevant federal rules.

 Significant alternatives. The significant alternatives to this rule, especially those 

that might minimize potential impacts on small entities, are presented in the remainder of 

this section.

As required by section 609(b) of the RFA, as amended by the Small Business 

Regulatory Enforcement Fairness Act (SBREFA), the EPA also convened a Small 

Business Advocacy Review Panel (Panel) to obtain advice and recommendations of 

representatives of the small entities that potentially would be subject to the rule's 

requirements. The following paragraphs describe the process, the type of small entity 

representatives, the outreach efforts and the Panel members. 
Page 109 of 326

Well before beginning the formal SBREFA process, the EPA actively engaged in 

outreach with HPBA, MHA and PFI and many of their member companies to discuss the 

rule under development and to provide these contacts with an early opportunity to ask 

questions and discuss their concerns.42 The EPA provided each small business with 

general information on the SBREFA process and background information on the NSPS 

rulemaking process and current schedule. 

Based on consultations with the SBA, and resulting from solicited selfnominations, we prepared a list of 30 potential Small Entity Representatives (SERs), 

from residential wood heating appliance manufacturers (wood heaters, pellet 

heaters/stoves, hydronic heaters, forced-air furnaces and masonry heaters), other woodburning appliance manufacturers (fireplaces, cook stoves), equipment suppliers, chimney 

sweeps, test laboratories, masons and trade associations. Once the official pre-Panel 

process began and potential SERs were identified, the EPA held an outreach meeting 

with the potential SERs and invited representatives from the Office of Advocacy of the 

Small Business Administration (OA/SBA) and the Office of Information and Regulatory 

Affairs within the Office of Management and Budget (OIRA/OMB) on June 29, 2010, to 

solicit their feedback on the upcoming proposed rulemaking. Representatives from 26 of 

the 30 companies and organizations that we selected as potential SERs for this SBREFA 

process participated in the meeting (in person and by phone). At that meeting, the EPA 

solicited written comments from the potential SERs, which were later summarized and 

shared with the Panel as part of the convening document.

 

42 Also, as noted in the proposal preamble in the discussion of development of the 

proposed hydronic heater emission limits, the EPA worked with the hydronic heater 

industry in 2006 to develop a voluntary partnership program to encourage manufacture of 

cleaner models, www.epa.gov/burnwise/participation. 
Page 110 of 326

The SBAR Panel convened on August 4, 2010. The Panel consisted of 

representatives of the EPA, OA/SBA and OIRA/OMB. The Panel held a formal outreach 

meeting/teleconference with the SERs on August 25, 2010. To help the SERs prepare for 

this meeting, on August 11, 2010, the Panel sent a list of questions, preliminary cost 

information and other materials to each of the SERs via email. Additional materials were 

emailed to the SERs on August 19, 2010. The Panel provided the opportunity for 

questions and comment during the meeting on various aspects of the proposal being 

developed, including the expanded scope of the rule, changes to the current requirements 

under consideration, preliminary cost information and follow up from the June 29, 2010, 

meeting on the SERs’ ideas for regulatory flexibility. During the August 25 meeting, 

SERs voiced general support for the planned proposed rule and shared specific concerns 

with the Panel members. As a result of this meeting, the EPA received many useful 

verbal comments, and the EPA received many helpful written comments by September 

10, 2010. 

Consistent with the RFA/SBREFA requirements, the Panel evaluated the 

assembled materials and small-entity comments on issues related to elements of the 

Interim Regulatory Flexibility Analysis. A copy of the Panel final full report is included 

in the docket for this rule. We have attempted to follow the Panel’s recommendations to 

the degree we can while also ensuring that the options are practicable, enforceable, 

environmentally sound and consistent with the CAA. For those recommendations not 

adopted by the EPA, we included an explanation at proposal for why we rejected them.

Further information about the panel is provided in the FRFA and the SBREFA 

Panel final report that are included in the docket for this rule.
Page 111 of 326

In addition, the EPA is preparing a Small Entity Compliance Guide to help small 

entities comply with this rule. Small entities can obtain of a copy of this guide at 

http://www.epa.gov/rfa/compliance-guides.html or http://www2.epa.gov/residentialwood-heaters. We expect the Small Entity Compliance Guide to be available by April 

2015.

D. Unfunded Mandates Reform Act (UMRA)

This action does not contain any unfunded mandates of $100 million or more as 

described in UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect 

small governments. This action imposes no enforceable duty on any state, local or tribal 

governments. The nationwide annualized average compliance cost of this rule for directly 

affected appliances is $45.7 million/yr in the 2015-2020 timeframe (2013$). Therefore, 

this final rule is not be subject to the requirements of sections 202 or 205 of the UMRA.

This final rule is also not subject to the requirements of section 203 of UMRA 

because it contains no regulatory requirements that might significantly or uniquely affect 

small governments. The rule does not apply to such governments and will impose no 

obligations upon them.

E. Executive Order 13132: Federalism

This action does not have federalism implications. It will not have substantial 

direct effects on the states, on the relationship between the national government and the 

states, or on the distribution of power and responsibilities among the various levels of 

government.

The rule will not impose any requirements on state and local governments. Thus, 

Executive Order 13132 does not apply to this final rule. Although section 6 of Executive 
Page 112 of 326

Order 13132 does not apply to this final action, the EPA did consult with representatives 

of state and local governments in developing this action. In the spirit of Executive Order 

13132 and consistent with the EPA policy to promote communications between the EPA 

and state and local governments, the EPA solicited comment on the proposed rule from 

state and local officials. We have responded to their significant comments in this 

preamble and in the RTC document.

F. Executive Order 13175: Consultation and Coordination with Indian Tribal

Governments

This action does not have tribal implications as specified in Executive Order 

13175. This rule will not impose any requirements on tribal governments. Thus, 

Executive Order 13175 does not apply to this action. 

Consistent with the EPA Policy on Consultation and Coordination with Indian 

Tribes, the EPA consulted with tribal officials during the development of this action. A 

summary of that consultation is provided here. During the development of the proposed 

rulemaking, the EPA conducted outreach with numerous tribal representatives to provide 

opportunities for input prior to development of the proposed rule. We provided 

information at the July 2010, National Tribal Forum/National Tribal Air Association 

(NTAA) meeting in Albuquerque, New Mexico, and the November 2010, EPA Region 

10 Tribal Leaders Summit in Juneau, Alaska. We also presented information on this 

proposed rulemaking in the April 2010, issue of Tribal Air News and during the 

EPA/NTAA tribal workgroup conference calls (April 2010, July 2010, August 2010, and 

May 2013). Specifically, we received input from the EPA/NTAA tribal workgroup 

members on culturally relevant exclusions from the proposed standards. We agreed with 
Page 113 of 326

their input, clarified that we do not intend to regulate ceremonial fires, and added a 

definition to the rule to exclude traditional Native American bake ovens.

On February 18, 2011, the EPA mailed letters to about 600 elected tribal leaders 

in the U.S. offering an opportunity for consultation on this proposal. We received 

requests from six tribes. These tribes agreed to discuss this proposal with us in a 

conference call held on March 22, 2011. The tribes were very supportive of this proposal 

and provided some helpful clarifications of definitions (e.g., Native American bake 

ovens) that we have incorporated in this proposal. We continued to provide updates on 

the rule on the EPA/NTAA conference calls and to offer opportunities to tribal leaders for 

consultation. On January 30, 2014, and September 25, 2014, we presented updates for 

tribes at the monthly EPA/NTAA conference calls.

The air quality and public health benefits to be achieved by this rule will benefit 

tribes. The emissions occur in neighborhoods and affect people in their homes. To the 

extent that populations are particularly sensitive to asthma, this rule will help. 

G. Executive Order 13045: Protection of Children from Environmental Health Risks and 

Safety Risks

This action is not subject to Executive Order 13045 because the EPA does not 

believe the environmental health risks or safety risks addressed by this action present a 

disproportionate risk to children. This action’s health and risk assessments are contained 

in the RIA as well as the report “Analysis of Exposure to Residential Wood Combustion

Emissions for Different Socio-Economic Groups”43 which shows that on a nationwide 

basis, cancer risks due to residential wood smoke emissions among disadvantaged 

 

43 “Analysis of Exposure to Residential Wood Combustion Emissions for Different 

Socio-Economic Groups, Revised Draft Report.” Prepared for Gil Wood, U.S. EPA, 
Page 114 of 326

population groups generally are lower than the risks for the general population due to 

residential wood smoke emissions. One of the demographic variables examined for this 

report was that of people 18 years and younger. The full report is available in the docket.

This final rule is expected to reduce environmental impacts for everyone, 

including children. This action promulgates emissions limits at the levels based on BSER, 

as required by the CAA. Based on our analysis, we believe this rule will not have a 

disproportionate impact on children, and, in fact, will result in improvements to 

children’s health. These emissions happen in neighborhoods and affect people in their 

homes. To the extent that children are particularly sensitive to asthma, this rule will help. 

H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect 

Energy Supply, Distribution, or Use

This action is not a “significant energy action” because it is not likely to have a 

significant adverse effect on the supply, distribution or use of energy. Further, we have 

concluded that this rule is not likely to have any significant adverse energy effects. In 

general, we expect the NSPS to improve technology, including energy efficiency. 

Reducing emissions and increasing efficiency might increase the use of wood fuel, which 

would relieve pressure on traditional coal or petroleum based energy sources. However, 

as described in section VI.E, it is difficult to determine the precise energy impacts that 

might result from this rule. This is because wood-fueled appliances compete with other 

biomass forms as well as more traditional oil, electricity and natural gas. Robust data are 

not available to determine the potential conversion to other types of fuels and their 

 

Office of Air Quality Planning and Standards, Research Triangle Park, NC. Prepared by 

EC/R Inc., EPA Contract No. EP-D-05-085, Work Assignment No. 4-3. April 22, 2010.
Page 115 of 326

associated appliances if the consumer costs of wood-fueled appliances increase and at 

what level that increase would drive consumer choice.

I. National Technology Transfer and Advancement Act (NTTAA)

This action involves technical standards. The EPA has decided to use several 

VCS ASTM test methods, in full or in part, including the following: E2515-11 “Standard 

Test Method for Determination of Particulate Matter Emissions Collected by a Dilution 

Tunnel;” E2779-10 “Standard Test Method for Determining Particulate Matter Emissions 

from Pellet Heaters;” E2780-10 “Standard Test Method for Determining Particulate 

Matter Emissions from Wood Heaters;” and E2618-13 “Standard Test Method for 

Measurement of Particulate Matter Emissions and Heating Efficiency of Outdoor Solid 

Fuel-Fired Hydronic Heating Appliances.” These VCS test methods are available for 

from the American Society for Testing and Material (ASTM), 100 Barr Harbor Drive, 

P.O. Box CB700, West Conshohocken, Pennsylvania 19428–2959, (800) 262–1373, 

http://www.astm.org. A hard copy of this material is also available for viewing in the 

docket for this rule (Docket ID# EPA-HQ-OAR-2009-0734), the EPA Docket Center, 

Public Reading Room, EPA West, Room 3334, 1301 Constitution Ave., NW, 

Washington, DC. Also, we will use, in part, the following test VCS CSA method 

available at the CSA web site http://shop.csa.ca/en/canada/fuel-burningequipment/b4151-10/invt/27013322010/: CSA B415.1-10 “Performance Testing of 

Solid-fuel-burning Heating Appliances.” A hard copy of this material is also available for 

viewing in the docket for this rule (Docket ID# EPA-HQ-OAR-2009-0734) at the EPA 

Docket Center located at the address above. Finally, we will use, in part, the following 

VCS test method prepared by the European Union: EN 303-5 “Heating boilers for solid 
Page 116 of 326

fuels, hand and automatically stoked nominal heat output of up to 1025 MBtu –

Terminology, requirements, testing, and marketing.” This European National (EN) 

standards material is available for purchase at http://www.en-standard.eu/csn-en-303-5-

heating-boilers-part-5-heating-boilers-for-solid-fuels-manually-and-automatically-stokednominal-heat-output-of-up-to-500-kw-terminology-requirements-testing-andmarking/?gclid=CMv3wrbFrsACFU4F7Aod3yoAcw. A hard copy of this material is also 

available for viewing in the docket for this rule (Docket ID# EPA-HQ-OAR-2009-0734), 

at the EPA Docket Center located at the address above. We believe that all the methods 

listed above have some positive aspects that can help stakeholders determine emissions 

under various operation conditions. For more details, please refer to section 6 of the RTC 

document.

In addition, we determined that the VCS ASTM E871-82 (Reapproved 2013), 

“Standard Test Method for Moisture Analysis of Particulate Wood Fuels” is acceptable as 

an alternative to that portion of the EPA Methods 5H and 28.

The search identified five other VCS that were potentially applicable for this rule 

in lieu of the EPA reference methods. However, the EPA determined that the five 

candidate VCS would not be applicable and practical due to lack of equivalency, 

documentation, validation data and other important technical and policy considerations. 

The five VCS and other information and conclusion, including the search and review 

results, are in the docket for this rule. The EPA solicited comments on this aspect of the 

proposed rulemaking. Specifically, we invited the public to identify potentially applicable 

voluntary consensus standards and to explain why such standards, in whole or in part, 

should or should not be used in this regulation. The EPA’s responses to the significant 
Page 117 of 326

comments are presented in section V of this preamble and in section 6 of the RTC 

document.

J. Executive Order 12898: Federal Actions to Address Environmental Justice in Minority 

Populations and Low-Income Populations

The EPA believes the human health or environmental risk addressed by this 

action will not have potential disproportionately high and adverse human health or 

environmental effects on minority, low-income or indigenous populations because it does 

not affect the level of protection provided to human health or the environment. The 

results of this evaluation are contained in the report “Analysis of Exposure to Residential 

Wood Combustion Emissions for Different Socio-Economic Groups” which shows that 

on a nationwide basis, cancer risks due to residential wood smoke emissions among 

disadvantaged population groups generally are lower than the risks for the general 

population due to residential wood smoke emissions.44 Rather, the rule increases the level 

of environmental protection for all affected populations without having any 

disproportionately high and adverse human health or environmental effects on any 

population, including any minority, low-income or indigenous population.

This rule establishes national standards that will reduce primarily PM emissions 

from new residential wood heaters and, thus, is expected to decrease the amount of these 

emissions to which all affected populations are exposed. These emissions happen in many 

neighborhoods nationwide, including in minority and low-income neighborhoods and 

 

44 “Analysis of Exposure to Residential Wood Combustion Emissions for Different 

Socio-Economic Groups, Revised Draft Report.” Prepared for Gil Wood, U.S. EPA, 

Office of Air Quality Planning and Standards, Research Triangle Park, NC. Prepared by 

EC/R Inc., EPA Contract No. EP-D-05-085, Work Assignment No. 4-3. April 22, 2010.
Page 118 of 326

affect people in their homes. To the extent that minority populations and low-income 

populations are more vulnerable, this rule will help. 

K. Congressional Review Act (CRA)

This action is subject to the CRA, and the EPA will submit a rule report to each 

House of the Congress and to the Comptroller General of the United States. This action is 

a “major rule” as defined by 5 U.S.C. 804(2). 
Page 119 of 326

Page 118 of 326 - Standards of Performance for New Residential Wood Heaters, 

New Residential Hydronic Heaters and Forced-Air Furnaces

List of Subjects in 40 CFR Part 60

Environmental protection, Administrative practice and procedure, Air pollution 

control, Carbon monoxide, Hazardous substances, Intergovernmental relations, 

Particulate matter, Reporting and recordkeeping requirements.

_____________________________________

Dated

______________________________________

Gina McCarthy,

Administrator.
Page 120 of 326

For the reasons stated in the preamble, title 40, chapter I, of the Code of Federal 

Regulations is amended as set forth below. 

PART 60 – STANDARDS OF PERFORMANCE FOR NEW SOURCES

1. The authority citation for part 60 continues to read as follows:

Authority: 42 U.S.C. 7401 et seq.

Subpart A—GENERAL PROVISIONS

2. Section 60.17 is amended by adding paragraphs (g)(202) through (206), (s) and 

(t) to read as follows:

§ 60.17 Incorporations by reference.

* * * * *

(g) * * *The following material is available for purchase from the American 

Society for Testing and Material (ASTM), 100 Barr Harbor Drive, P.O. Box CB700, 

West Conshohocken, Pennsylvania 19428–2959, (800) 262–1373, http://www.astm.org. 

A hard copy of this material is also available for viewing in the docket for this rule 

(Docket ID number EPA-HQ-OAR-2009-0734), the EPA Docket Center, Public Reading 

Room, EPA West, Room 3334, 1301 Constitution Ave., NW, Washington, DC

(202) ASTM E871-82 (Reapproved 2013), Standard Test Method for Moisture 

Analysis of Particulate Wood Fuels, IBR approved for Appendix A-8: Method 28R.

(203) ASTM E2515-11, Standard Test Method for Determination of Particulate 

Matter Emissions Collected by a Dilution Tunnel, IBR approved for § 60.534 and § 

60.5476.

(204) ASTM E2779-10, Standard Test Method for Determining Particulate Matter 

Emissions from Pellet Heaters, IBR approved for § 60.534.
Page 121 of 326

(205) ASTM E2618-13 Standard Test Method for Measurement of Particulate 

Matter Emissions and Heating Efficiency of Outdoor Solid Fuel-Fired Hydronic Heating 

Appliances, IBR approved for § 60.5476.

(206) ASTM E2780-10, Standard Test Method for Determining Particulate Matter 

Emissions from Wood Heaters, IBR approved for Appendix A: Method 28R.

* * * * *

(s) This material is available for purchase from the Canadian Standards 

Association (CSA) at http://shop.csa.ca/en/canada/fuel-burning-equipment/b4151-

10/invt/27013322010/. A hard copy of this material is also available for viewing in the

docket for this rule (Docket ID number EPA-HQ-OAR-2009-0734), the EPA Docket 

Center, Public Reading Room, EPA West, Room 3334, 1301 Constitution Ave., NW, 

Washington, DC.

(1) CSA B415.1-10, Performance Testing of Solid-fuel-burning Heating 

Appliances, IBR approved for § 60.534 and § 60.5476.

(2) [Reserved]

(t) This European National (EN) standards material is available for purchase at 

http://www.en-standard.eu/csn-en-303-5-heating-boilers-part-5-heating-boilers-for-solidfuels-manually-and-automatically-stoked-nominal-heat-output-of-up-to-500-kwterminology-requirements-testing-andmarking/?gclid=CMv3wrbFrsACFU4F7Aod3yoAcw. A hard copy of this material is also 

available for viewing in the docket for this rule (Docket ID number EPA-HQ-OAR-2009-

0734), the EPA Docket Center, Public Reading Room, EPA West, Room 3334, 1301 

Constitution Ave., NW, Washington, DC.
Page 122 of 326

(1) EN 303-5, Heating boilers - Part 5: Heating boilers for solid fuels, manually 

and automatically stoked, nominal heat output of up to 500 kW - Terminology, 

requirements, testing and marking, IBR approved for § 60.5476.

(2) [Reserved]

3. Part 60 is amended by revising subpart AAA to read as follows:

Subpart AAA—Standards of Performance for New Residential Wood Heaters

Sec.

60.530 Am I subject to this subpart?

60.531 What definitions must I know?

60.532 What standards and associated requirements must I meet and by when?

60.533 What compliance and certification requirements must I meet and by when?

60.534 What test methods and procedures must I use to determine compliance with the 

standards and requirements for certification?

60.535 What procedures must I use for EPA approval of a test laboratory or EPA 

approval of a third-party certifier?

60.536 What requirements must I meet for permanent labels, temporary labels (hangtags), 

and owner's manuals?

60.537 What records must I keep and what reports must I submit?

60.538 What activities are prohibited under this subpart?

60.539 What hearing and appeal procedures apply to me?

60.539a Who implements and enforces this subpart?

60.539b What parts of the General Provisions do not apply to me?

Subpart AAA—Standards of Performance for New Residential Wood Heaters
Page 123 of 326

§ 60.530 Am I subject to this subpart?

(a) You are subject to this subpart if you manufacture, sell, offer for sale, import 

for sale, distribute, offer to distribute, introduce or deliver for introduction into commerce 

in the United States, or install or operate an affected wood heater specified in paragraphs 

(a)(1) or (a)(2) of this section, except as provided in paragraph (c) of this section.

(1) Each adjustable burn rate wood heater, single burn rate wood heater and pellet 

stove manufactured on or after July 1, 1988, with a current EPA certificate of compliance 

issued prior to [INSERT DATE 60 DAYS AFTER DATE OF PUBLICATION IN 

THE FEDERAL REGISTER] according to the certification procedures in effect in this 

subpart at the time of certification is an affected wood heater.

(2) All other residential wood heaters as defined in §60.531 manufactured or sold 

on or after [INSERT DATE 60 DAYS AFTER DATE OF PUBLICATION IN THE 

FEDERAL REGISTER] are affected wood heaters, except as provided in paragraph (c) 

of this section.

(b) Each affected wood heater must comply with the provisions of this subpart

unless exempted under paragraphs (b)(1) through (b)(6) of this section. These exemptions 

are determined by rule applicability and do not require EPA notification or public notice. 

(1) Affected wood heaters manufactured in the United States for export are 

exempt from the applicable emission limits of § 60.532 and the requirements of § 60.533.

(2) Affected wood heaters used for research and development purposes that are 

never offered for sale or sold and that are not used for the purpose of providing heat are 

exempt from the applicable emission limits of § 60.532 and the requirements of § 60.533. 
Page 124 of 326

No more than 50 wood heaters manufactured per model line can be exempted for this 

purpose.

(3) Appliances that do not burn wood or wood pellets (such as coal-only heaters 

that meet the definition in § 60.531 or corn-only pellet stoves) are exempt from the 

applicable emission limits of § 60.532 and the requirements of § 60.533 provided that all 

advertising and warranties exclude wood burning. 

(4) Cook stoves as defined in § 60.531 are exempt from the applicable emission 

limits of § 60.532 and the requirements of § 60.533.

(5) Camp stoves as defined in § 60.531 are exempt from the applicable emission 

limits of § 60.532 and the requirements of § 60.533.

(6) Modification or reconstruction, as defined in § 60.14 and § 60.15 of subpart A

of this part does not, by itself, make a wood heater an affected facility under this subpart.

(c) The following are not affected wood heaters and are not subject to this 

subpart:

(1) Residential hydronic heaters and residential forced-air furnaces subject to 

subpart QQQQ of this part.

(2) Residential masonry heaters that meet the definition in § 60.531.

(3) Appliances that are not residential heating devices (for example, manufactured 

or site-built masonry fireplaces).

(4) Traditional Native American bake ovens that meet the definition in § 60.531.

§ 60.531 What definitions must I know?

As used in this subpart, all terms not defined herein have the meaning given them 

in the Clean Air Act and subpart A of this part.
Page 125 of 326

Adjustable burn rate wood heater means a wood heater that is equipped with or 

installed with a damper or other mechanism to allow the operator to vary burn rate 

conditions, regardless of whether it is internal or external to the appliance. This definition 

does not distinguish between heaters that are free standing, built-in or fireplace inserts.

Approved test laboratory means a test laboratory that is approved for wood heater 

certification testing under § 60.535 or is an independent third-party test laboratory that is 

accredited under ISO-IEC Standard 17025 to perform testing using the test methods 

specified in § 60.534 by an accreditation body that is a full member signatory to the 

International Laboratory Accreditation Cooperation Mutual Recognition Arrangement

and approved by the EPA for conducting testing under this subpart. 

Camp stove (sometimes also called cylinder stove or wall tent stove) means a 

portable stove equipped with a pipe or chimney exhaust capable of burning wood or coal 

intended for use in a tent or other temporary structure used for hunting, camping, fishing 

or other outdoor recreation. The primary purpose of the stove is to provide space heating, 

although cooking and heating water may be additional functions.

Catalytic combustor means a device coated with a noble metal used in a wood 

heater to lower the temperature required for combustion.

Chip wood fuel means wood chipped into small pieces that are uniform in size, 

shape, moisture, density and energy content. 

Coal-only heater means an enclosed, coal-burning appliance capable of space 

heating or space heating and domestic water heating, which is marketed and warranted 

solely as a coal-only heater and has all of the following characteristics:
Page 126 of 326

(1) An opening for emptying ash that is located near the bottom or the side of the 

appliance;

(2) A system that admits air primarily up and through the fuel bed;

(3) A grate or other similar device for shaking or disturbing the fuel bed or a 

power-driven or mechanical stoker;

(4) Installation instructions, owner’s manual and marketing information that state 

that the use of wood in the stove, except for coal ignition purposes, is prohibited by law; 

and

(5) A safety listing as a coal-only heater, except for coal ignition 

purposes, under accepted American or Canadian safety codes, as 

documented by a permanent label from a nationally recognized certification 

body.

Commercial owner means any person who owns or controls a wood 

heater in the course of the business of the manufacture, importation, 

distribution (including shipping and storage), or sale of the wood heater.

Cook stove means a wood-fired appliance that is designed, marketed and 

warranted primarily for cooking food and that has the following characteristics:

(1) An oven, with volume of 0.028 cubic meters (1 cubic foot) or greater, and an 

oven rack;

(2) A device for measuring oven temperatures;

(3) A flame path that is routed around the oven;

(4) An ash pan;

(5) An ash clean-out door below the oven;
Page 127 of 326

(6) The absence of a fan or heat channels to dissipate heat from the appliance;

(7) A cooking surface with an area measured in square inches or square feet that 

is at least 1.5 times greater than the volume of firebox measured in cubic inches or cubic 

feet. Example: A cook stove with a firebox of 2 cubic feet must have a cooking surface of 

at least 3 square feet;

(8) A portion of at least four sides of the oven (which may include the bottom 

and/or top) is exposed to the flame path during the heating cycle of the oven. A flue gas 

bypass may exist for temperature control.

Fireplace means a wood-burning appliance intended to be used primarily for 

aesthetic enjoyment and not as a space heater. An appliance is a fireplace if it is in a 

model line that satisfies the requirements in paragraphs (1), (2) or (3) of this definition.

(1) The model line includes a safety listing under recognized American or 

Canadian safety standards, as documented by a permanent label from a nationally 

recognized certification body affixed on each unit sold, and that said safety listing only 

allows operation of the fireplace with doors fully open. Operation with any required 

safety screen satisfies this requirement.

(2) The model line has a safety listing that allows operation with doors closed, has 

no user-operated controls other than flue or outside air dampers that can only be adjusted 

to either a fully closed or fully opened position, and the requirements in either paragraph 

(2)(i) or (2)(ii) of this definition are satisfied. 

(i) Appliances are sold with tempered glass panel doors only (either as standard or

optional equipment), or

(ii) The fire viewing area is equal to or greater than 500 square inches.
Page 128 of 326

(3)(i) A model line that is clearly positioned in the marketplace as intended to be 

used primarily for aesthetic enjoyment and not as a room heater, as demonstrated by 

product literature (including owner’s manuals), advertising targeted at the trade or public 

(including web-based promotional materials) or training materials is presumptively a 

fireplace model line. 

(ii) The presumption in paragraph (3)(i) of this definition can be rebutted by test 

data from an EPA-approved test laboratory reviewed by an EPA-approved third-party 

certifier that were generated when operating the appliance with the door(s) closed, and 

that demonstrate an average stack gas carbon dioxide (CO2) concentration over the 

duration of the test run equal to or less than 5.00 percent and a ratio of the average stack 

gas CO2 to the average stack gas carbon monoxide (CO) equal to or greater than 

15:1. The stack gas average CO2 and CO concentrations for the test run shall be 

determined in accordance with the requirements in CSA B415.1-10, clause 6.3, using a 

sampling interval no greater than 1 minute. The average stack gas CO2 and CO 

concentrations for purposes of this determination shall be the average of the stack gas 

concentrations from all sampling intervals over the full test run.

Manufactured means completed and ready for shipment (whether or not 

assembled or packaged) for purposes of determining the date of manufacture.

Manufacturer means any entity that constructs or imports into the United States a 

wood heater.

Model line means all wood heaters offered for sale by a single manufacturer that 

are similar in all material respects that would affect emissions as defined in this section. 
Page 129 of 326

Particulate matter (PM) means total particulate matter including coarse 

particulate (PM10) and fine particulate (PM2.5).

Pellet fuel means refined and densified fuel shaped into small pellets or briquettes 

that are uniform in size, shape, moisture, density and energy content. 

Pellet stove (sometimes called pellet heater or pellet space heater) means an 

enclosed, pellet or chip fuel-burning device capable of and intended for residential space 

heating or space heating and domestic water heating. Pellet stoves include a fuel storage 

hopper or bin and a fuel feed system. Pellet stoves include, but are not limited to:

(1) Free-standing pellet stoves – pellet stoves that are installed on legs or on a 

pedestal or other supporting base. These stoves generally are safety listed under ASTM 

E1509, UL-1482, ULC S627 or ULC-ORD C1482.

(2) Pellet stove fireplace inserts – pellet stoves intended to be installed in masonry 

fireplace cavities or in other enclosures. These stoves generally are safety listed under 

ASTM E1509, UL-1482, ULC-S628 or ULC-ORD C1482. 

(3) Built-in pellet stoves – pellet stoves intended to be recessed into the wall. 

These stoves generally are safety listed under ASTM E1509, UL-127, ULC-S610 or 

ULC-ORD C1482.

Representative affected wood heater means an individual wood heater that is 

similar in all material respects that would affect emissions to other wood heaters within 

the model line it represents.

Residential masonry heater means a factory-built or site-built wood-burning 

device in which the heat from intermittent fires burned rapidly in the firebox is stored in 

the refractory mass for slow release to building spaces. Masonry heaters are site-built
Page 130 of 326

(using local materials or a combination of local materials and manufactured components) 

or site-assembled (using factory-built components), solid fuel-burning heating appliances 

constructed mainly of refractory materials (e.g., masonry materials or soapstone. They 

typically have an interior construction consisting of a firebox and heat exchange channels 

built from refractory components, through which flue gases are routed. ASTM E-1602 

“Standard Guide for Construction of Solid Fuel Burning Masonry Heaters” provides 

design and construction information for the range of masonry heaters most commonly 

built in the United States. The site-assembled models are generally listed to UL-1482. 

Sale means the transfer of ownership or control, except that a transfer of control 

of an affected wood heater for research and development purposes within the scope of § 

60.530(b)(2) is not a sale.

Similar in all material respects that would affect emissions means that the 

construction materials, exhaust and inlet air systems and other design features are within 

the allowed tolerances for components identified in § 60.533(k)(2), (3) and (4).

Single burn rate wood heater means a wood heater that is not equipped with or 

installed with a burn control device to allow the operator to vary burn rate conditions. 

Burn rate control devices include stack dampers that control the outflow of flue gases 

from the heater to the chimney, whether built into the appliance, sold with it, or 

recommended for use with the heater by the manufacturer, retailer or installer; and air 

control slides, gates or any other type of mechanisms that control combustion air flow 

into the heater.

Sold at retail means the sale by a commercial owner of a wood heater to the 

ultimate purchaser/user or noncommercial purchaser.
Page 131 of 326

Third-party certifier (sometimes called third-party certifying body or product 

certifying body) means an independent third party that is accredited under ISO-IEC 

Standards 17025 and 17065 to perform certifications, inspections and audits by an 

accreditation body that is a full member signatory to the International Laboratory 

Accreditation Cooperation Mutual Recognition Arrangement and approved by the EPA 

for conducting certifications, inspections and audits under this subpart.

Traditional Native American bake oven means a wood or other solid fuel burning 

appliance that is designed primarily for use by Native Americans for food preparation, 

cooking, warming or for instructional, recreational, cultural or ceremonial purposes.

Unseasoned wood means wood with an average moisture content of 20 percent or 

more.

Valid certification test means a test that meets the following criteria:

(1) The Administrator was notified about the test in accordance with § 60.534(g); 

(2) The test was conducted by an approved test laboratory as defined in this 

section;

(3) The test was conducted on a wood heater similar in all material respects that 

would affect emissions to other wood heaters of the model line that is to be certified; and

(4) The test was conducted in accordance with the test methods and procedures 

specified in § 60.534.

Wood heater means an enclosed, wood burning-appliance capable of and intended 

for residential space heating or space heating and domestic water heating. These devices 

include, but are not limited to, adjustable burn rate wood heaters, single burn rate wood 

heaters and pellet stoves. Wood heaters may or may not include air ducts to deliver some 
Page 132 of 326

portion of the heat produced to areas other than the space where the wood heater is 

located. Wood heaters include, but are not limited to:

(1) Free-standing Wood Heaters –Wood Heaters that are installed on legs, on a 

pedestal or suspended from the ceiling. These products generally are safety listed under 

UL-1482, UL-737 or ULC-S627.

(2) Fireplace Insert Wood Heaters – Wood Heaters intended to be installed in 

masonry fireplace cavities or in other enclosures. These appliances generally are safety 

listed under UL-1482, UL-737 or ULC-S628. 

(3) Built-in Wood Heaters – Wood Heaters that are intended to be recessed into 

the wall. These appliances generally are safety listed under UL-1482, UL-737, UL-127 or 

ULC-S610.

§ 60.532 What standards and associated requirements must I meet and by when?

(a) 2015 Particulate Matter Emission Standards. Unless exempted under § 

60.530(b), each affected wood heater manufactured on or after [INSERT DATE 60 

DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER] or sold 

at retail for use in the United States on or after December 31, 2015, must not discharge 

into the atmosphere any gases that contain particulate matter in excess of a weighted 

average of 4.5 g/hr (0.010 lb/hr). Compliance for all heaters must be determined by the 

test methods and procedures in § 60.534. 

(b) 2020 Particulate Matter Emission Standards. Unless exempted under § 

60.530(b) or electing to use the cord wood alternative means of compliance option in 

paragraph (c) of the section, each affected wood heater manufactured or sold at retail for 

use in the United States on or after [INSERT DATE 60 DAYS PLUS 5 YEARS 
Page 133 of 326

AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER] must not 

discharge into the atmosphere any gases that contain particulate matter in excess of a 

weighted average of 2.0 g/hr (0.0044 lb/hr). Compliance for all heaters must be 

determined by the test methods and procedures in § 60.534.

(c) 2020 Cord Wood Alternative Compliance Option. Each affected wood heater 

manufactured or sold at retail for use in the United States on or after [INSERT DATE 60 

DAYS PLUS 5 YEARS AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER] must not discharge into the atmosphere any gases that contain particulate 

matter in excess of a weighted average of 2.5 g/hr (0.0055 lb/hr). Compliance must be 

determined by a cord wood test method approved by the Administrator and the 

procedures in § 60.534.

(d) Chip Wood Fuel Requirements. Operators of wood heaters that are certified to 

burn chip wood fuels must only burn chip wood fuels that have been specified in the 

owner’s manual. The chip wood fuel must meet the following minimum requirements: 

(1) Moisture content: less than 35 percent

(2) Inorganic fines: less than or equal to 1 percent;

(3) Chlorides: less than or equal to 300 parts per million by weight; 

(4) Ash content: no more than 2 percent;

(5) No demolition or construction waste; and

(6) Trace metals: less than 100 mg/kg.

(e) Pellet Fuel Requirements. Operators of wood heaters that are certified to burn 

pellet fuels must only burn pellets that have been specified in the owner’s manual and 

graded under a licensing agreement with a third-party organization approved by the EPA. 
Page 134 of 326

The Pellet Fuels Institute, ENplus and CANplus are initially deemed to be approved 

third-party organizations for this purpose, and additional organizations may apply to the 

Administrator for approval. The pellet fuel must meet the following minimum 

requirements as assured through a quality assurance program licensed by a third-party 

organization approved by the EPA:

(1) Density: consistent hardness and energy content with a minimum density of 38 

pounds/cubic foot; 

(2) Dimensions: maximum length of 1.5 inches and diameter between 0.230 and 

0.285 inches; 

(3) Inorganic fines: less than or equal to 1 percent;

(4) Chlorides: less than or equal to 300 parts per million by weight; 

(5) Ash content: no more than 2 percent;

(6) Contains no demolition or construction waste;

(7) Trace metals: less than 100 mg/kg; and

(8) None of the prohibited fuels in (f).

(f) Prohibited Fuel Types. No person is permitted to burn any of the following 

materials in an affected wood heater:

(1) Residential or commercial garbage;

(2) Lawn clippings or yard waste;

(3) Materials containing rubber, including tires;

(4) Materials containing plastic;

(5) Waste petroleum products, paints or paint thinners, or asphalt products;

(6) Materials containing asbestos;
Page 135 of 326

(7) Construction or demolition debris;

(8) Paper products, cardboard, plywood, or particleboard. The prohibition against 

burning these materials does not prohibit the use of fire starters made from paper, 

cardboard, sawdust, wax and similar substances for the purpose of starting a fire in an 

affected wood heater; 

(9) Railroad ties, pressure-treated wood or pallets;

(10) Manure or animal remains; 

(11) Salt water driftwood or other previously salt water saturated materials;

(12) Unseasoned wood;

(13) Any materials that are not included in the warranty and owner’s manual for 

the subject wood heater; or

(14) Any materials that were not included in the certification tests for the subject 

wood heater.

(g) Operation of Affected Wood Heaters. The user of an affected residential wood 

heater must operate the heater in a manner consistent with the owner’s manual. The 

owner’s manual must clearly specify that operation in a manner inconsistent with the 

owner’s manual would void the warranty.

(h) Temperature Sensor Requirement. An affected wood heater equipped with a 

catalytic combustor must be equipped with a temperature sensor that can monitor 

combustor gas stream temperatures within or immediately downstream [within 2.54 

centimeters (1 inch)] of the catalytic combustor surface.

§ 60.533 What compliance and certification requirements must I meet and by when?
Page 136 of 326

(a) Certification Requirement. Each affected wood heater must be certified to be 

in compliance with the applicable emission standards and other requirements of this 

subpart. For each model line manufactured or sold by a single entity (e.g., company or 

manufacturer), compliance with applicable emission standards of § 60.532 must be 

determined based on testing of representative affected wood heaters within the model 

line. If one entity licenses a model line to another entity, each entity’s model line must be 

certified. If an entity intends to change the name of the entity or the name of the model, 

the manufacturer must apply for a new certification 60 days before the intended name 

change.

(1) Except for model lines meeting the requirements of paragraph (h)(1) of this 

section, on or after [INSERT DATE 60 DAYS AFTER DATE OF PUBLICATION 

IN THE FEDERAL REGISTER], the manufacturer must submit to the Administrator

the information required in paragraph (b) of this section and follow either the certification 

process in paragraphs (c) through (e) of this section or the third-party certifier-based 

application process specified in paragraph (f) of this section. 

(2) On or after [INSERT DATE 60 DAYS PLUS 1 YEAR AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER], the manufacturer must submit the 

information required in paragraph (b) of this section and follow the third-party certifierbased application process specified in paragraph (f) of this section.

(b) Application for a Certificate of Compliance. Any manufacturer of an affected 

wood heater must apply to the Administrator for a certificate of compliance for each 

model line. The application must be submitted to: WoodHeaterReports@epa.gov. The 
Page 137 of 326

application must be signed by a responsible representative of the manufacturer or an 

authorized representative and must contain the following:

(1) The model name and design number. The model name and design number 

must clearly distinguish one model from another. The name and design number cannot 

include the EPA symbol or logo or name or derivatives such as “EPA.” 

(2) Engineering drawings and specifications of components that may affect 

emissions (including specifications for each component listed in paragraph (k)(2), (3) and 

(4) of this section). Manufacturers may use assembly or design drawings that have been 

prepared for other purposes, but must designate on the drawings the dimensions of each 

component listed in paragraph (k) of this section. Manufacturers must identify tolerances 

of components listed in paragraph (k)(2) of this section that are different from those 

specified in that paragraph, and show that such tolerances cannot reasonably be 

anticipated to cause wood heaters in the model line to exceed the applicable emission 

limits. The drawings must identify how the emission-critical parts, such as air tubes and 

catalyst, can be readily inspected and replaced. 

(3) A statement whether the firebox or any firebox component (including the 

materials listed in paragraph (k)(3) of this section) will be composed of material different

from the material used for the firebox or firebox component in the wood heater on which 

certification testing was performed, a description of any such differences and 

demonstration that any such differences may not reasonably be anticipated to adversely 

affect emissions or efficiency.

(4) Clear identification of any claimed confidential business information (CBI). 

Submit such information under separate cover to the EPA CBI Office; Attn: Residential 
Page 138 of 326

Wood Heater Compliance Program Lead, 1200 Pennsylvania Ave., NW, Washington, 

DC 20004. Note that all emissions data, including all information necessary to determine 

emission rates in the format of the standard, cannot be claimed as CBI.

(5) All documentation pertaining to a valid certification test, including the 

complete test report and, for all test runs: Raw data sheets, laboratory technician notes, 

calculations and test results. Documentation must include the items specified in the 

applicable test methods. Documentation must include discussion of each test run and its 

appropriateness and validity, and must include detailed discussion of all anomalies, 

whether all burn rate categories were achieved, any data not used in the calculations and, 

for any test runs not completed, the data collected during the test run and the reason(s) 

that the test run was not completed and why. The burn rate for the low burn rate category 

must be no greater than the rate that an operator can achieve in home use and no greater 

than is advertised by the manufacturer or retailer. The test report must include a summary 

table that clearly presents the individual and overall emission rates, efficiencies and heat 

outputs. Submit the test report and all associated required information, according to the 

procedures for electronic reporting specified in § 60.537(f).

(6) A copy of the warranties for the model line, which must include a statement 

that the warranties are void if the unit is used to burn materials for which the unit is not 

certified by the EPA and void if not operated according to the owner’s manual.

(7) A statement that the manufacturer will conduct a quality assurance program 

for the model line that satisfies the requirements of paragraph (m) of this section.
Page 139 of 326

(8) A statement describing how the tested unit was sealed by the laboratory after 

the completion of certification testing and asserting that such unit will be stored by the 

manufacturer in the sealed state until 5 years after the certification test.

(9) Statements that the wood heaters manufactured under this certificate will be—

(i) Similar in all material respects that would affect emissions as defined in § 

60.531 to the wood heater submitted for certification testing, and

(ii) Labeled as prescribed in § 60.536.

(iii) Accompanied by an owner’s manual that meets the requirements in § 60.536. 

In addition, a copy of the owner’s manual must be submitted to the Administrator and be 

available to the public on the manufacturer’s web site.

(10) A statement that the manufacturer has entered into contracts with an 

approved laboratory and an approved third-party certifier that satisfy the requirements of 

paragraph (f) of this section.

(11) A statement that the approved laboratory and approved third-party certifier 

are allowed to submit information on behalf of the manufacturer, including any claimed 

to be CBI.

(12) A statement that the manufacturer will place a copy of the certification test 

report and summary on the manufacturer’s web site available to the public within 30 days 

after the Administrator issues a certificate of compliance.

(13) A statement of acknowledgment that the certificate of compliance cannot be 

transferred to another manufacturer or model line without written approval by the 

Administrator.
Page 140 of 326

(14) A statement acknowledging that it is unlawful to sell, distribute or offer to 

sell or distribute an affected wood heater without a valid certificate of compliance.

(15) Contact information for the responsible representative of the manufacturer 

and all authorized representatives, including name, affiliation, physical address, 

telephone number and email address.

(c) Administrator Approval Process. (1) The Administrator may issue a certificate 

of compliance for a model line if the Administrator determines, based on all information 

submitted by the applicant and any other relevant information available, that:

(i) A valid certification test demonstrates that the representative affected wood 

heater complies with the applicable emission standards in § 60.532;

(ii) Any tolerances or materials for components listed in paragraph (k)(2) or (3) of 

this section that are different from those specified in those paragraphs may not reasonably 

be anticipated to cause wood heaters in the model line to exceed the applicable emission 

limits; and

(iii) The requirements of paragraph (b) of this section have been met. 

(2) The Administrator will deny certification if the Administrator determines that 

the criteria in paragraph (c)(1) of this section have not been satisfied. Upon denying 

certification under this paragraph, the Administrator will give written notice to the 

manufacturer setting forth the basis for this determination.

(d) Level of Compliance Certification. The Administrator will issue the certificate

of compliance for the most stringent particulate matter emission standard that the tested 

representative wood heater meets under § 60.532.
Page 141 of 326

(e) Conditional, Temporary Certificate of Compliance. A conditional, temporary 

certificate of compliance may be granted by the Administrator until [INSERT DATE 60 

DAYS PLUS 1 YEAR AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER] based on the manufacturer’s submittal of a complete certification 

application meeting all the requirements in § 60.533(b). The application must include the 

full test report by an EPA-approved laboratory and all required compliance statements by 

the manufacturer with the exception of a certificate of conformity by an EPA-approved 

third-party certifier. The conditional, temporary certificate of compliance would allow 

manufacture and sales of the affected wood heater model line until [INSERT DATE 60 

DAYS PLUS 1 YEAR AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER] or until the Administrator completes the review of the application, 

whichever is earlier. By [INSERT DATE 60 DAYS PLUS 1 YEAR AFTER DATE 

OF PUBLICATION IN THE FEDERAL REGISTER], the manufacturer must submit 

a certificate of conformity by an EPA-approved third-party certifier.

(f) Third-party Certifier-Based Application Process. 

(1) Any manufacturer of an affected wood heater must apply to the Administrator 

for a certificate of compliance for each model line. The manufacturer must meet the 

following requirements: 

(i) The manufacturer must contract with a third-party certifier for certification 

services. The contract must include regular (at least annual) unannounced audits under 

ISO-IEC Standard 17065 to ensure that the manufacturer’s quality assurance plan is 

being implemented. The contract must also include a report for each audit under ISO-IEC 

Standard 17065 that fully documents the results of the audit. The contract must include
Page 142 of 326

authorization and requirement for the third-party certifier to submit all such reports to the 

Administrator and the manufacturer within 30 days of the audit. The audit report must 

identify deviations from the manufacturer’s quality assurance plan and specify the

corrective actions that need to be taken to address each identified deficiency. 

(ii) The manufacturer must submit the materials specified in paragraph (b) of this 

section and a quality assurance plan that meets the requirements of paragraph (m) of this 

section to the third-party certifier. The quality assurance plan must ensure that units 

within a model line will be similar in all material respects that would affect emissions to 

the wood heater submitted for certification testing, and it must include design drawings 

for the model line.

(iii) The manufacturer must apply to the third-party certifier for a certification of 

conformity with the applicable requirements of this subpart for the model line.

(A) After testing by an approved test laboratory is complete, certification of 

conformity with the emission standards in § 60.532 must be performed by the 

manufacturer’s contracted third-party certifier. 

(B) The third-party certifier may certify conformity if the emission tests have 

been conducted per the appropriate guidelines; the test report is complete and accurate;

the instrumentation used for the test was properly calibrated; the test report shows that the 

representative affected wood heater meets the applicable emission limits specified in § 

60.532; the quality assurance plan is adequate to ensure that units within the model line 

will be similar in all material respects that would affect emissions to the wood heater 

submitted for certification testing; and that the affected heaters would meet all applicable 

requirements of this subpart. 
Page 143 of 326

(iv) The manufacturer must then submit to the Administrator an application for a 

certificate of compliance that includes the certification of conformity, quality assurance

plan, test report and all supporting documentation specified in paragraph (b) of this 

section.

(v) The submission also must include a statement signed by a responsible official 

of the manufacturer or authorized representative that the manufacturer has complied with 

and will continue to comply with all requirements of this subpart for certificate of 

compliance and that the manufacturer remains responsible for compliance regardless of 

any error by the test laboratory or third-party certifier.

(2) The Administrator will issue to the manufacturer a certificate of compliance 

for a model line if it is determined, based on all of the information submitted in the 

application for certification and any other relevant information, that:

(i) A valid certification of conformity has demonstrated that the representative 

affected wood heater complies with the applicable emission standards in § 60.532;

(ii) Any tolerances or materials for components listed in paragraph (k)(2) or (3) of 

this section that are different from those specified in those paragraphs may not be 

reasonably anticipated to cause wood heaters in the model line to exceed the applicable 

emission limits;

(iii) The requirements of paragraphs (b) of this section have been met; and

(iv) A valid certificate of conformity for the model line has been prepared and 

submitted.

(3) The Administrator will deny certification if the Administrator determines that 

the criteria in paragraph (f)(2) of this section have not been satisfied. Upon denying 
Page 144 of 326

certification under this paragraph, the Administrator will give written notice to the 

manufacturer setting forth the basis for the determination.

(g) Waiver from Submitting Test Results. An applicant for certification may apply 

for a potential waiver of the requirement to submit the results of a certification test 

pursuant to paragraph (b)(5) of this section, if the wood heater meets either of the

following conditions:

(1) The wood heaters of the model line are similar in all material respects that 

would affect emissions, as defined in § 60.531, to another model line that has already 

been issued a certificate of compliance. A manufacturer that seeks a waiver of 

certification testing must identify the model line that has been certified, and must submit 

a copy of an agreement with the owner of the design permitting the applicant to produce 

wood heaters of that design.

(2) The manufacturer has previously conducted a valid certification test to 

demonstrate that the wood heaters of the model line meet the applicable standard 

specified in § 60.532. 

(h) Certification Period. Unless revoked sooner by the Administrator, a certificate 

of compliance will be valid for the following periods as applicable:

(1) For a model line that was previously certified as meeting the 1990 Phase II 

emission standards under the 1988 NSPS, in effect prior to [INSERT DATE 60 DAYS 

AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER], at an 

emission level equal to or less than the 2015 emission standards in § 60.532(a), the model 

line is deemed to have a certificate of compliance for the 2015 emission standards in § 

60.532(a), which is valid until the effective date for the 2020 standards in § 60.532(b) 
Page 145 of 326

(i.e., until [INSERT DATE 60 DAYS PLUS 5 YEARS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER]).

(2) For a model line certified as meeting emission standards in § 60.532, a 

certificate of compliance will be valid for 5 years from the date of issuance or until a 

more stringent standard comes into effect, whichever is sooner.

(i) Renewal of Certification.

(1) The manufacturer must request renewal of a model line’s certificate of 

compliance or recertify the model line every 5 years, or the manufacturer may choose to 

no longer manufacture or sell that model line after the expiration date. If the 

manufacturer chooses to no longer manufacture that model line, then the manufacturer 

must submit a statement to the Administrator to that effect. 

(2) A manufacturer of an affected wood heater model line may apply to the 

Administrator for potential renewal of its certificate of compliance by submitting the 

material specified in paragraph (b) and following the procedures specified in paragraph 

(f) of this section, or by affirming in writing that the wood heaters in the model line

continue to be similar in all material respects that would affect emissions to the 

representative wood heater submitted for testing on which the original certificate of 

compliance was based and requesting a potential waiver from certification testing. The 

application must include a copy of the review of the draft application and approval by the 

third-party certifier. 

(3) If the Administrator grants a renewal of certification, the Administrator will 

give written notice to the manufacturer setting forth the basis for the determination and 

issue a certification renewal.
Page 146 of 326

(4) If the Administrator denies the request for a renewal of certification, the 

Administrator will give written notice to the manufacturer setting forth the basis for the 

determination.

(5) If the Administrator denies the request for a renewal of certification, the 

manufacturer and retailer must not manufacture or sell the previously-certified wood 

heaters after the expiration date of the certificate of compliance.

(j) [Reserved]

(k) Recertification.

(1) The manufacturer must recertify a model line whenever any change is made in 

the design submitted pursuant to paragraph (b)(2) of this section that affects or is 

presumed to affect the particulate matter emission rate for that model line. The 

manufacturer of an affected wood heater must apply to the Administrator for potential 

recertification by submitting the material specified in paragraph (b) and following the 

procedures specified in paragraph (f) of this section, or by affirming in writing that the 

change will not cause wood heaters in the model line to exceed applicable emission limits 

and requesting a potential waiver from certification testing. The application for 

recertification must be reviewed and approved by the contracted third-party certifier and 

a copy of the review and approval must be included. The Administrator may waive this 

requirement upon written request by the manufacturer, if the manufacturer presents

adequate rationale and the Administrator determines that the change may not reasonably 

be anticipated to cause wood heaters in the model line to exceed the applicable emission 

limits. The granting of such a waiver does not relieve the manufacturer of any 

compliance obligations under this subpart.
Page 147 of 326

(2) Any change in the design tolerances or actual dimensions of any of the 

following components (where such components are applicable) is presumed to affect 

particulate matter and carbon monoxide emissions and efficiency if that change exceeds 

±0.64 cm (±1/4 inch) for any linear dimension and ±5 percent for any cross-sectional area 

relating to air introduction systems and catalyst bypass gaps unless other dimensions and 

cross-sectional areas are previously approved by the Administrator under paragraph 

(c)(1)(ii) of this section:

(i) Firebox: Dimensions;

(ii) Air introduction systems: Cross-sectional area of restrictive air inlets and 

outlets, location and method of control;

(iii) Baffles: Dimensions and locations;

(iv) Refractory/insulation: Dimensions and location;

(v) Catalyst: Dimensions and location;

(vi) Catalyst bypass mechanism and catalyst bypass gap tolerances (when bypass 

mechanism is in closed position): Dimensions, cross-sectional area, and location;

(vii) Flue gas exit: Dimensions and location;

(viii) Door and catalyst bypass gaskets: Dimensions and fit;

(ix) Outer thermal shielding and thermal coverings: Dimensions and location;

(x) Fuel feed system: For wood heaters that are designed primarily to burn pellet

fuel or wood chips and other wood heaters equipped with a fuel feed system, the fuel feed 

rate, auger motor design and power rating, and the angle of the auger to the firebox; and

(xi) Forced-air combustion system: For wood heaters so equipped, the location 

and horsepower of blower motors and the fan blade size.
Page 148 of 326

(3) Any change in the materials used for the following components is presumed to 

affect particulate matter emissions and efficiency:

(i) Refractory/insulation; or

(ii) Door and catalyst bypass gaskets.

(4) A change in the make, model or composition of a catalyst is presumed to 

affect particulate matter and carbon monoxide emissions and efficiency, unless the 

change has been requested by the heater manufacturer and has been approved in advance 

by the Administrator, based on test data that demonstrate that the replacement catalyst is 

equivalent to or better than the original catalyst in terms of particulate matter emission 

reduction.

(l) Criteria for Revocation of Certification.

(1) The Administrator may revoke certification if it is determined that the wood 

heaters being manufactured or sold in that model line do not comply with the 

requirements of this subpart. Such a determination will be based on all available 

evidence, including but not limited to:

(i) Test data from a retesting of the original unit on which the certification test 

was conducted or a unit that is similar in all material respects that would affect emissions;

(ii) A finding that the certification test was not valid. The finding will be based on 

problems or irregularities with the certification test or its documentation, but may be 

supplemented by other information;

(iii) A finding that the labeling of the wood heater model line, the owner’s manual 

or the associated marketing information does not comply with the requirements of § 

60.536;
Page 149 of 326

(iv) Failure by the manufacturer to comply with reporting and recordkeeping 

requirements under § 60.537;

(v) Physical examination showing that a significant percentage (as defined in the 

quality assurance plan approved pursuant to paragraph (m) of this section, but no larger 

than 1 percent) of production units inspected is not similar in all material respects that 

would affect emissions to the representative affected wood heater submitted for 

certification testing; 

(vi) Failure of the manufacturer to conduct a quality assurance program in 

conformity with paragraph (m) of this section; or

(vii) Failure of the approved laboratory to test the wood heater using the methods 

specified in § 60.534.

(2) Revocation of certification under this paragraph (l) will not take effect until 

the manufacturer concerned has been given written notice by the Administrator setting 

forth the basis for the proposed determination and an opportunity to request a hearing

under § 60.539. 

(m) Quality Assurance Program. On or after [INSERT DATE 60 DAYS PLUS 1 

YEAR AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER], for 

each certified model line, the manufacturer must conduct a quality assurance program 

that satisfies the requirements of paragraphs (m)(1) through (5) of this section. The 

quality assurance program requirements of this paragraph (m) supersede the quality 

assurance plan requirements previously specified in § 60.533(o) that was in effect prior to 

[INSERT DATE 60 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER]. The manufacturer of a model line with a compliance certification under 
Page 150 of 326

paragraph (h)(1) of this section must conduct a quality assurance program that satisfies 

the requirements of this paragraph (m) by [INSERT DATE 60 DAYS PLUS 1 YEAR 

AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].

(1) The manufacturer must prepare and operate according to a quality assurance 

plan for each certified model line that includes specific inspection and testing 

requirements for ensuring that all units within a model line are similar in all material 

respects that would affect emissions to the wood heater submitted for certification testing 

and meet the emissions standards in § 60.532.

(2) The quality assurance plan must be approved by the third-party certifier as 

part of the certification of conformity process specified in paragraph (f) of this section.

(3) The quality assurance plan must include regular (at least annual) unannounced 

audits by the third-party certifier under ISO-IEC Standard 17065 to ensure that the 

manufacturer’s quality assurance plan is being implemented. 

(4) The quality assurance plan must include a report for each audit under ISO-IEC 

Standard 17065 that fully documents the results of the audit. The third-party certifier 

must be authorized and required to submit all such reports to the Administrator and the 

manufacturer within 30 days of the audit. The audit report must identify deviations from 

the manufacturer’s quality assurance plan and specify the corrective actions that need to 

be taken to address each identified deficiency. 

(5) Within 30 days after receiving each audit report, the manufacturer must report 

to the third-party certifier and to the Administrator its corrective actions and responses to 

any deficiencies identified in the audit report. No such report is required if an audit report 

did not identify any deficiencies.
Page 151 of 326

(n) EPA Compliance Audit Testing.

(1)(i) The Administrator may select by written notice wood heaters or model lines

for compliance audit testing to determine compliance with the emission standards in § 

60.532. 

(ii) The Administrator will transmit a written notification of the selected wood 

heaters or model line(s) to the manufacturer, which will include the name and address of 

the laboratory selected to perform the audit test and the model name and serial number of 

the wood heater(s) or model line(s) selected to undergo audit testing.

(2)(i) The Administrator may test, or direct the manufacturer to have tested, a 

wood heater or a wood heater from the model line(s) selected under paragraph (n)(1)(i) of 

this section in a laboratory approved under § 60.535. The Administrator may select any 

approved test laboratory or federal laboratory for this audit testing.

(ii) The expense of the compliance audit test is the responsibility of the wood 

heater manufacturer.

(iii) The test must be conducted using the same test method used to obtain 

certification. If the certification test consisted of more than one particulate matter 

sampling test method, the Administrator may direct the manufacturer and test laboratory

as to which of these methods to use for the purpose of audit testing. The Administrator 

will notify the manufacturer at least 30 days prior to any test under this paragraph, and 

allow the manufacturer and/or his authorized representatives to observe the test.

(3) Revocation of Certification.

(i) If emissions from a wood heater tested under paragraph (n)(2) of this section 

exceed the applicable emission standard by more than 50 percent using the same test 
Page 152 of 326

method used to obtain certification, the Administrator will notify the manufacturer that 

certification for that model line is suspended effective 72 hours from the receipt of the 

notice, unless the suspension notice is withdrawn by the Administrator. The suspension 

will remain in effect until withdrawn by the Administrator, or the date 30 days from its 

effective date if a revocation notice under paragraph (n)(3)(ii) of this section is not issued 

within that period, or the date of final agency action on revocation, whichever occurs 

earliest.

(ii)(A) If emissions from a wood heater tested under paragraph (n)(2) of this 

section exceed the applicable emission limit, the Administrator will notify the 

manufacturer that certification is revoked for that model line.

(B) A revocation notice under paragraph (n)(3)(ii)(A) of this section will become 

final and effective 60 days after the date of written notification to the manufacturer, 

unless it is withdrawn, a hearing is requested under § 60.539(a)(2), or the deadline for 

requesting a hearing is extended.

(C) The Administrator may extend the deadline for requesting a hearing for up to 

60 days for good cause.

(D) A manufacturer may extend the deadline for requesting a hearing for up to 6 

months, by agreeing to a voluntary suspension of certification.

(iii) Any notification under paragraph (n)(3)(i) or (n)(3)(ii) of this section will 

include a copy of a preliminary test report from the approved test laboratory or federal 

test laboratory. The test laboratory must provide a preliminary test report to the 

Administrator within 14 days of the completion of testing, if a wood heater exceeds the 

applicable emission limit in § 60.532. The test laboratory must provide the Administrator 
Page 153 of 326

and the manufacturer, within 30 days of the completion of testing, all documentation 

pertaining to the test, including the complete test report and raw data sheets, laboratory 

technician notes, and test results for all test runs.

(iv) Upon receiving notification of a test failure under paragraph (n)(3)(ii) of this 

section, the manufacturer may request that up to four additional wood heaters from the 

same model line be tested at the manufacturer’s expense, at the test laboratory that 

performed the emissions test for the Administrator.

(v) Whether or not the manufacturer proceeds under paragraph (n)(3)(iv) of this 

section, the manufacturer may submit any relevant information to the Administrator, 

including any other test data generated pursuant to this subpart. The manufacturer must 

bear the expense of any additional testing.

(vi) The Administrator will withdraw any notice issued under paragraph (n)(3)(ii) 

of this section if tests under paragraph (n)(3)(iv) of this section show either—

(A) That exactly four additional wood heaters were tested for the manufacturer 

and all four met the applicable emission limits; or

(B) That exactly two additional wood heaters were tested for the manufacturer 

and each of them met the applicable emission limits and the average emissions of all

three tested heaters (the original audit heater and the two additional heaters) met the 

applicable emission limits.

(vii) If the Administrator withdraws a notice pursuant to paragraph (n)(3)(vi) of 

this section, the Administrator will revise the certification values for the model line based 

on the test data and other relevant information. The manufacturer must then revise the 

model line’s labels and marketing information accordingly.
Page 154 of 326

(viii) The Administrator may withdraw any proposed revocation, if the 

Administrator finds that an audit test failure has been rebutted by information submitted 

by the manufacturer under paragraph (n)(3)(iv) of this section and/or (n)(3)(v) of this 

section or by any other relevant information available to the Administrator.

§ 60.534 What test methods and procedures must I use to determine compliance 

with the standards and requirements for certification?

Test methods and procedures specified in this section or in appendices of this part, 

except as provided under § 60.8(b), must be used to determine compliance with the 

standards and requirements for certification under §§ 60.532 and 60.533 and for reporting

carbon monoxide emissions and efficiency as follows:

(a)(1) For affected wood heaters subject to the 2015 and 2020 particulate matter 

emission standards of §§ 60.532(a) and (b), the manufacturer must have an EPAapproved test laboratory conduct testing according to paragraphs (a)(1)(i) or (ii) of this 

section. The manufacturer or manufacturer’s authorized representative must submit a 

summary and the full test reports with all supporting information, including detailed 

discussion of all anomalies, whether all burn rate categories were properly achieved, any 

data not used in the calculations and, for any test runs not completed, the data that were 

collected and the reason that the test run was not completed. The burn rate for the low 

burn rate category must be no greater than the rate that an operator can achieve in home 

use and no greater than is advertised by the manufacturer or retailer. The manufacturer 

has the option of submitting test results obtained pursuant to either paragraph (a)(1)(i) or 

(ii) of this section to the Administrator as specified under § 60.537 as part of a request for 

a certification of compliance.
Page 155 of 326

(i) Conduct testing with crib wood using EPA Method 28R of Appendix A-8 of 

this part or an alternative crib wood test method approved by the Administrator or the 

ASTM E2779-10 pellet heater test method to establish the certification test conditions 

and the particulate matter emission values. 

(ii) Conduct testing with cord wood using an alternative cord wood test method 

approved by the Administrator to establish the certification test conditions and the 

particulate matter emission values.

(2) For the 2020 cord wood alternative means of compliance option specified in § 

60.532(c), the manufacturer must have an EPA-approved test laboratory conduct testing 

with cord wood using an alternative cord wood test method approved by the 

Administrator to establish the certification test conditions and the particulate matter 

emission values. 

(b) [Reserved].

(c) For affected wood heaters subject to the 2015 and 2020 particulate matter 

emission standards specified in §§ 60.532(a), (b) and (c), particulate matter emission 

concentrations must be measured with ASTM E2515-11. Four-inch filters and Teflon 

membrane filters or Teflon-coated glass fiber filters may be used in ASTM E-2515-11.

(d) For all tests conducted using ASTM E2515-11 pursuant to this section, the 

manufacturer and approved test laboratory must also measure the first hour of particulate 

matter emissions for each test run using a separate filter in one of the two parallel trains. 

The manufacturer and approved test laboratory must report the test results for the first 

hour separately and also include them in the total particulate matter emissions per run. 
Page 156 of 326

(e) The manufacturer must have the approved test laboratory measure the 

efficiency, heat output and carbon monoxide emissions of the tested wood heater using

Canadian Standards Administration (CSA) Method B415.1-10, section 13.7.

(f) Douglas fir may be used in ASTM E2779-10, ASTM E2780-10 and CSA 

B415.1-10.

(g) The manufacturer of an affected wood heater model line must notify the 

Administrator of the date that certification testing is scheduled to begin by email to 

WoodHeaterReports@epa.gov. This notice must be received by the EPA at least 30 days 

before the start of testing. The notification of testing must include the manufacturer's 

name and physical and email addresses, the approved test laboratory's name and physical 

and email addresses, the third-party certifier name, the model name and number (or, if 

unavailable, some other way to distinguish between models), and the dates of testing. The 

laboratory may substitute certification testing of another affected wood heater on the 

original date in order to ensure regular laboratory testing operations. 

(h) The approved test laboratory must allow the manufacturer, the manufacturer’s 

approved third-party certifier, the EPA and delegated state regulatory agencies to observe 

certification testing. However, manufacturers must not involve themselves in the conduct 

of the test after the pretest burn has begun. Communications between the manufacturer 

and laboratory or third-party certifier personnel regarding operation of the wood heater 

must be limited to written communications transmitted prior to the first pretest burn of 

the certification test series. During certification tests, the manufacturer may communicate 

with laboratory personnel only in writing and only to notify them that the manufacturer 

has observed a deviation from proper test procedures. All communications must be 
Page 157 of 326

included in the test documentation required to be submitted pursuant to § 60.533(b)(5) 

and must be consistent with instructions provided in the owner's manual required under § 

60.536(g), except to the extent that they address details of the certification tests that 

would not be relevant to owners or regulators.

§ 60.535 What procedures must I use for EPA approval of a test laboratory or EPA 

approval of a third-party certifier? 

(a) Test Laboratory Approval. (1) A laboratory must apply to the Administrator 

for approval to test under this rule by submitting documentation that the laboratory is 

accredited by a nationally recognized accrediting entity under ISO-IEC Standard 17025 

to perform testing using the test methods specified under § 60.534. Laboratories 

accredited by EPA prior to [INSERT DATE 60 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER] may have until [INSERT DATE 3 

YEARS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER] to 

submit documentation that they have accreditation under ISO-IEC Standard 17025 to 

perform testing using the test methods specified under § 60.534. ISO accreditation is 

required for all other laboratories performing testing beginning on [INSERT DATE 60 

DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].

(2) As part of the application, the test laboratory must:

(i) Agree to participate biennially in an independently operated proficiency testing 

program with no direct ties to the participating laboratories;

(ii) Agree to allow the Administrator, regulatory agencies and third-party 

certifiers access to observe certification testing;
Page 158 of 326

(iii) Agree to comply with calibration, reporting and recordkeeping requirements 

that affect testing laboratories; and

(iv) Agree to perform a compliance audit test at the manufacturer’s expense at the 

testing cost normally charged to such manufacturer if the laboratory is selected by the 

Administrator to conduct the compliance audit test of the manufacturer’s model line. The 

test laboratory must provide a preliminary audit test report to the Administrator within 14 

days of the completion of testing, if the tested wood heater exceeds the applicable 

emission limit in § 60.532. The test laboratory must provide the Administrator and the 

manufacturer, within 30 days of the completion of audit testing, all documentation 

pertaining to the test, including the complete test report and raw data sheets, laboratory 

technician notes, and test results for all test runs.

(v) Have no conflict of interest and receive no financial benefit from the outcome 

of certification testing conducted pursuant to § 60.533.

(vi) Agree to not perform initial certification tests on any models manufactured by

a manufacturer for which the laboratory has conducted research and development design 

services within the last 5 years.

(vii) Agree to seal any wood heater on which it performed certification tests, 

immediately upon completion or suspension of certification testing, by using a 

laboratory-specific seal.

(viii) Agree to immediately notify the Administrator of any suspended tests 

through email and in writing, giving the date suspended, the reason(s) why, and the 

projected date for restarting. The laboratory must submit the operation and test data 

obtained, even if the test is not completed. 
Page 159 of 326

(3) If the EPA approves the laboratory, the Administrator will provide the test 

laboratory with a certificate of approval for testing under this rule. If the EPA does not 

approve the laboratory, the Administrator will give written notice to the laboratory setting 

forth the basis for the determination.

(b) Revocation of Test Laboratory Approval. (1) The Administrator may revoke 

the EPA laboratory approval if it is determined that the laboratory:

(i) Is no longer accredited by the accreditation body;

(ii) Does not follow required procedures or practices;

(iii) Has falsified data or otherwise misrepresented emission data;

(iv) Has failed to participate in a proficiency testing program, in accordance with 

its commitment under paragraph (a)(2)(i) of this section; or

(v) Has failed to seal a wood heater in accordance with paragraph (a)(2)(vii) of 

this section.

(2) Revocation of approval under this paragraph (b) will not take effect until the 

laboratory concerned has been given written notice by the Administrator setting forth the 

basis for the proposed determination and an opportunity for a hearing under § 60.539. 

However, if revocation is ultimately upheld, all tests conducted by the laboratory after 

written notice was given will, at the discretion of the Administrator, be declared invalid.

(c) Period of Test Laboratory Approval (1) With the exception of laboratories 

meeting the provisions of paragraph (c)(2) of this section, and unless revoked sooner, a 

certificate of approval for testing under this rule is valid for 5 years from the date of 

issuance.
Page 160 of 326

(2) Laboratories accredited by the EPA by [INSERT DATE 60 DAYS AFTER 

DATE OF PUBLICATION IN THE FEDERAL REGISTER], under the provisions of 

§ 60.535 as in effect prior to that date may continue to be EPA accredited and deemed 

EPA approved for testing under this subpart until [INSERT DATE 60 DAYS PLUS 3 

YEARS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER], at 

which time the EPA accreditation and approval ends unless the laboratory has obtained 

accreditation under § 60.535 as in effect on that date.

(d) Third-Party Certifier Approval. (1) A third-party certifier may apply to the 

Administrator for approval to be an EPA-approved third-party certifier by submitting 

credentials demonstrating that it has been accredited by a nationally recognized 

accrediting entity to perform certifications and inspections under ISO-IEC Standard 

17025, ISO-IEC Standard 17065 and ISO-IEC Standard 17020.

(2) As part of the application, the third-party certifier must:

(i) Agree to offer to contract with wood heater manufacturers to perform thirdparty certification activities according to the requirements of this subpart;

(ii) Agree to periodically conduct audits as described in § 60.533(m) and the 

manufacturer’s quality assurance program; 

(iii) Agree to comply with reporting and recordkeeping requirements that affect 

approved wood heater testing laboratories and third-party certifiers;

(iv) Have no conflict of interest and receive no financial benefit from the outcome 

of certification testing conducted pursuant to § 60.533; 

(v) Agree to make available to the Administrator supporting documentation for 

each wood heater certification and audit; and
Page 161 of 326

(vi) Agree to not perform initial certification reviews on any models 

manufactured by a manufacturer for which the third-party certifier has conducted 

research and development design services within the last 5 years.

(3) If approved, the Administrator will provide the third-party certifier with a 

certificate of approval. The approval will expire 5 years after being issued unless renewed 

by the third-party certifier. If the EPA denies the approval, the Administrator will give 

written notice to the third-party certifier for the basis for the determination.

(e) Revocation of Third-Party Certifier Approval. (1) The Administrator will 

revoke a third-party certifier’s EPA approval if it is determined that the certifier;

(i) Is no longer accredited by the accreditation body;

(ii) Does not follow required procedures or practices; or

(iii) Has falsified certification data or otherwise misrepresented emission data.

(2) Revocation of approval under this paragraph (e) will not take effect until the 

certifier concerned is given written notice by the Administrator setting forth the basis for 

the proposed determination and an opportunity for a hearing under § 60.539. However, if 

revocation is upheld, all certifications by the certifier after written notice was given will, 

at the discretion of the Administrator, be declared invalid.

§ 60.536 What requirements must I meet for permanent labels, temporary labels 

(hangtags) and owner's manuals?

(a) General Permanent Label Requirements.

(1) Each affected wood heater manufactured on or after the date the applicable 

standards come into effect as specified in § 60.532, must have a permanent label affixed 

to it that meets the requirements of this section.
Page 162 of 326

(2) Except for wood heaters subject to § 60.530(b)(1) through (b)(5), the 

permanent label must contain the following information:

(i) Month and year of manufacture of the individual unit;

(ii) Model name or number; 

(iii) Certification test emission value, test method and standard met (e.g., 2015, 

2020 crib wood, or 2020 cord wood); and

(iv) Serial number.

(3) The permanent label must:

(i) Be affixed in a readily visible or readily accessible location in such a manner 

that it can be easily viewed before and after the appliance is installed (an easilyremovable facade may be used for aesthetic purposes, however the bottom of a freestanding heater is not considered to be readily visible or readily accessible);

(ii) Be at least 8.9 cm long and 5.1 cm wide (3 1/2 inches long and 2 inches wide);

(iii) Be made of a material expected to last the lifetime of the wood heater;

(iv) Present the required information in a manner so that it is likely to remain 

legible for the lifetime of the wood heater; and

(v) Be affixed in such a manner that it cannot be removed from the appliance 

without damage to the label.

(4) The permanent label may be combined with any other label, as long as the 

required information is displayed, the integrity of the permanent label is not 

compromised, and the permanent label meets the requirements in § 60.536(a)(3).

(5) Any label statement under paragraph (b) or (c) of this section constitutes a 

representation by the manufacturer as to any wood heater that bears it:
Page 163 of 326

(i) That a certification of compliance was in effect at the time the wood heater left 

the possession of the manufacturer;

(ii) That the manufacturer was, at the time the label was affixed, conducting a 

quality assurance program in conformity with § 60.533(m); and

(iii) That all wood heaters individually tested for emissions by the manufacturer 

under its quality assurance program pursuant to § 60.533(m) met the applicable emissions 

limits.

(b) Permanent Label Requirements for Adjustable Burn Rate Wood Heaters and 

Pellet Stoves. If an adjustable burn rate wood heater or pellet stove belongs to a model 

line certified under § 60.533, and no wood heater in the model line has been found to 

exceed the applicable emission limits or tolerances through quality assurance testing, one 

of the following statements, as appropriate, must appear on the permanent label:

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Certified to comply with 2015 particulate emission standards.

Not approved for sale after [INSERT DATE 60 DAYS PLUS 5 YEARS AFTER 

DATE OF PUBLICATION IN THE FEDERAL REGISTER].”

or

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Certified to comply with 2020 particulate emission standards using crib wood.”

or

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Certified to comply with 2020 particulate emission standards using cord wood.”
Page 164 of 326

(c) Permanent Label Requirements for Single Burn Rate Wood Heaters. If the 

single burn rate wood heater belongs to a model line certified under § 60.533, and no 

heater in the model line has been found to exceed the applicable emission limits or 

tolerances through quality assurance testing, one of the following statements, as 

appropriate, must appear on the permanent label:

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Certified to comply with 2015 particulate emission standards for single burn rate heaters.

Not approved for sale after [INSERT DATE 60 DAYS PLUS 5 YEARS AFTER 

DATE OF PUBLICATION IN THE FEDERAL REGISTER].

This single burn rate wood heater is not approved for use with a flue damper.”

or

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Certified to comply with 2020 particulate emission standards for single burn rate heaters.

This single burn rate wood heater is not approved for use with a flue damper.”

(d) Additional Permanent Label Content. The permanent label for all certified 

wood heaters must also contain the following statement:

“This wood heater needs periodic inspection and repair for proper operation. 

Consult the owner's manual for further information. It is against federal regulations to 

operate this wood heater in a manner inconsistent with the operating instructions in the 

owner's manual.”

(e) Permanent Label Requirements for Affected Wood Heaters with Exemptions 

Under § 60.530(b). (1) If an affected wood heater is manufactured in the United States 
Page 165 of 326

for export as provided in § 60.530(b)(1), the following statement must appear on the 

permanent label:

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Export stove. May not be sold or operated within the United States.”

(2) If an affected wood heater is manufactured for use for research and 

development purposes as provided in § 60.530(b)(2), the following statement must 

appear on the permanent label:

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Not certified. Research Stove. Not approved for sale or for operation other than for 

research.”

(3) If a wood heater is exclusively a non-wood-burning heater as provided § 

60.530(b)(3), the following statement must appear on the permanent label:

“U.S. ENVIRONMENTAL PROTECTION AGENCY

This heater is not certified for wood burning. Use of any wood fuel is a violation of 

federal regulations.”

(4) If an affected wood heater is a cook stove that meets the definition in § 

60.531, the following statement must appear on the permanent label:

“U.S. ENVIRONMENTAL PROTECTION AGENCY

This unit is not a certified residential wood heater. The primary use for this unit is for 

cooking or baking.”

(5) If an affected wood heater is a camp stove that meets the definition in § 

60.531, the following statement must appear on the permanent label:

“U.S. ENVIRONMENTAL PROTECTION AGENCY
Page 166 of 326

This unit is not a certified residential wood heater. For portable and temporary use only.”

(f) Temporary Label (Hangtag) Voluntary Option.

(1) Each model certified to meet the 2020 particulate matter emission standards of 

§ 60.532(b) prior to [INSERT DATE 60 DAYS PLUS 5 YEARS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER] may display the temporary labels 

(hangtags) specified in section 3 of Appendix I of this part. The electronic template will 

be provided by the Administrator upon approval of the certification.

(2) The hangtags in paragraph (f)(1) of this section end on [INSERT DATE 60 

DAYS PLUS 5 YEARS AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER]

(3) Each model certified to meet the 2020 Cord Wood Alternative Compliance 

Option of § 60.532(c) may display the cord wood temporary label specified in section 3 

of Appendix I of this part. The electronic template will be provided by the Administrator 

upon approval of the certification.

(g) Owner’s Manual Requirements.

(1) Each affected wood heater offered for sale by a commercial owner must be 

accompanied by an owner's manual that must contain the information listed in paragraphs 

(g)(2) of this section (pertaining to installation) and paragraph (g)(3) of this section

(pertaining to operation and maintenance). Such information must be adequate to enable 

consumers to achieve optimal emissions performance. Such information must be 

consistent with the operating instructions provided by the manufacturer to the approved 

test laboratory for operating the wood heater during certification testing, except for 

details of the certification test that would not be relevant to the user. The commercial 
Page 167 of 326

owner must also make current and historical owner’s manuals available on the company 

web site and upon request to the EPA.

(2) Guidance on proper installation, include stack height, location and achieving 

proper draft.

(3) Proper operation and maintenance information, including minimizing visible 

emissions:

(i) Fuel loading and re-loading procedures; recommendations on fuel selection 

and warnings on what fuels not to use, such as unseasoned wood, treated wood, colored 

paper, cardboard, solvents, trash and garbage;

(ii) Fire starting procedures;

(iii) Proper use of air controls, including how to establish good combustion and 

how to ensure good combustion at the lowest burn rate for which the heater is warranted;

(iv) Ash removal procedures;

(v) Instructions for replacement of gaskets, air tubes and other parts that are 

critical to the emissions performance of the unit, and other maintenance and repair 

instructions;

(vi) For catalytic or hybrid models, information on the following pertaining to the 

catalytic combustor: Procedures for achieving and maintaining catalyst activity, 

maintenance procedures, procedures for determining deterioration or failure, procedures 

for replacement and information on how to exercise warranty rights; 

(vii) For catalytic or hybrid models, the following statement—

“This wood heater contains a catalytic combustor, which needs periodic inspection and 

replacement for proper operation. It is against federal regulations to operate this wood 
Page 168 of 326

heater in a manner inconsistent with operating instructions in this manual, or if the 

catalytic element is deactivated or removed.”

(viii) For noncatalytic models, the following statement—

“This wood heater needs periodic inspection and repair for proper operation. It is against 

federal regulations to operate this wood heater in a manner inconsistent with operating 

instructions in this manual.”

(4) Any manufacturer using the EPA-recommended language contained in 

Appendix I of this part to satisfy any requirement of this paragraph (g) will be considered 

to be in compliance with that requirement, provided that the particular language is printed 

in full, with only such changes as are necessary to ensure accuracy for the particular 

wood heater model line.

(h) Wood heaters that are affected by this subpart, but that have been owned and 

operated by a noncommercial owner, are not subject to paragraphs (f) and (g) of this 

section when offered for resale.

§ 60.537 What records must I keep and what reports must I submit?

(a)(1) Each manufacturer who holds a certificate of compliance pursuant to § 

60.533(c), (e) or (f) for a model line must maintain records containing the information 

required by paragraph (a)(2) through (4) of this section with respect to that model line for 

at least 5 years. 

(2) All documentation pertaining to the certification test used to obtain 

certification, including the full test report and raw data sheets, laboratory technician 

notes, calculations, the test results for all test runs, and discussions of the appropriateness 

and validity of all test runs, including runs attempted but not completed. The retained 
Page 169 of 326

certification test documentation must include, as applicable, detailed discussion of all 

anomalies, whether all burn rate categories were properly achieved, any data not used in 

the calculations and, for any test runs not completed, the data that were collected and the 

reason that the test run was not completed. The retained certification test also must 

include documentation that the burn rate for the low burn rate category was no greater 

than the rate that an operator can achieve in home use and no greater than is advertised by 

the manufacturer or retailer.

(3) Results of the quality assurance program inspections pursuant to § 60.533(m).

(4) For emissions tests conducted pursuant to the quality assurance program 

required by § 60.533(m), all test reports, data sheets, laboratory technician notes, 

calculations, and test results for all test runs, the corrective actions taken, if any, and any 

follow-up actions such as additional testing.

(b) Each approved test laboratory and third-party certifier must maintain records 

consisting of all documentation pertaining to each certification test, quality assurance 

program inspection and audit test, including the full test report and raw data sheets, 

technician notes, calculations, and the test results for all test runs. Each approved test 

laboratory must submit accreditation credentials and all proficiency test results to the 

Administrator. Each third-party certifier must submit each certification test, quality 

assurance program inspection report and ISO IEC accreditation credentials to the 

Administrator.

(c) Each manufacturer must retain each wood heater upon which certification tests 

were performed based upon which certification was granted under § 60.533(c) or (f) at 

the manufacturer's facility for a minimum of 5 years after the certification test. Each 
Page 170 of 326

wood heater must remain sealed and unaltered. Any such wood heater must be made 

available to the Administrator upon request for inspection and testing.

(d) Each manufacturer of an affected wood heater model line certified under § 

60.533(c) or (f) must submit a report to the Administrator every 2 years following 

issuance of a certificate of compliance for each model line. This report must include the 

sales for each model by state and certify that no changes in the design or manufacture of 

this model line have been made that require recertification under § 60.533(k).

(e)(1) Unless otherwise specified, all records required under this section must be 

maintained by the manufacturer, commercial owner of the affected wood heater, 

approved test laboratory or third-party certifier for a period of no less than 5 years.

(2) Unless otherwise specified, all reports to the Administrator required under this 

subpart must be made to: WoodHeaterReports@epa.gov.

(f) Within 60 days after the date of completing each performance test, e.g., initial 

certification test, tests conducted for quality assurance, and tests for renewal or 

recertification, each manufacturer must submit the performance test data electronically to 

WoodHeaterReports@epa.gov. Owners or operators who claim that some of the 

information being submitted is CBI (e.g., design drawings) must submit a complete file, 

including the information claimed to be CBI, on a compact disk or other commonly used 

electronic storage media (including, but not limited to, flash drives) by mail, and the 

same file, with the CBI omitted, electronically. The compact disk must be clearly marked 

as CBI and mailed to U.S. EPA, OECA CBI Office, Attention: Residential Wood Heater 

Compliance Program Lead, 1200 Pennsylvania Avenue NW, Washington, D.C. 20004. 

Emission data, including all information necessary to determine compliance, except 
Page 171 of 326

sensitive engineering drawings and sensitive detailed material specifications, may not be 

claimed as CBI.

(g) Within 30 days of receiving a certification of compliance for a model line, the 

manufacturer must make the full non-CBI test report and the summary of the test report 

available to the public on the manufacturer’s web site.

(h) Each manufacturer who uses the exemption for R&D heaters under § 60.530(b)(2)

must maintain records for at least 5 years documenting where the heaters were located, 

that the heaters were never offered for sale or sold and that the heaters were not used for 

the purpose of heating. § 60.538 What activities are prohibited under this subpart?

(a) No person is permitted to advertise for sale, offer for sale, sell or operate an 

affected wood heater that does not have affixed to it a permanent label pursuant to § 

60.536 (b) through (e), as applicable.

(b) No person is permitted to advertise for sale, offer for sale, or sell an affected 

wood heater labeled under § 60.536(e)(1) except for export. No person is permitted to 

operate an affected wood heater in the United States if it is labeled under § 60.536(d)(1).

(c)(1) No commercial owner is permitted to advertise for sale, offer for sale or sell 

an affected wood heater permanently labeled under § 60.536 (b) through (d), as 

applicable, unless:

(i) The affected wood heater has been certified to comply with the 2015 or 2020 

particulate matter emission standards pursuant to § 60.532, as applicable. This prohibition 

does not apply to wood heaters affected by this subpart that have been previously owned 

and operated by a noncommercial owner; and
Page 172 of 326

(ii) The commercial owner provides any purchaser or transferee with an owner's 

manual that meets the requirements of § 60.536(g) and a copy of the warranty.

(2) No commercial owner is permitted to advertise for sale, offer for sale, or sell 

an affected wood heater permanently labeled under § 60.536(e)(3), unless the affected 

wood heater has been certified to comply with the 2015 or 2020 particulate matter 

emission standards of § 60.532, as applicable.

(3) A commercial owner other than a manufacturer complies with the 

requirements of paragraph (c)(1) of this section if the commercial owner—

(i) Receives the required documentation from the manufacturer or a previous 

commercial owner; and

(ii) Provides that documentation unaltered to any person to whom the wood heater 

that it covers is sold or transferred.

(d)(1) In any case in which the Administrator revokes a certificate of compliance 

either for the submission of false or inaccurate information or other fraudulent acts, or 

based on a finding under § 60.533(l)(1)(ii) that the certification test was not valid, the 

Administrator may give notice of that revocation and the grounds for it to all commercial 

owners.

(2) On and after the date of receipt of the notice given under paragraph (d)(1) of 

this section, no commercial owner is permitted to sell any wood heater covered by the 

revoked certificate (other than to the manufacturer) unless the model line has been 

recertified in accordance with this subpart.
Page 173 of 326

(e) No person is permitted to install or operate an affected wood heater except in a 

manner consistent with the instructions on its permanent label and in the owner's manual 

pursuant to § 60.536(g), including only using fuels for which the unit is certified.

(f) No person is permitted to operate, sell or offer for sale an affected wood heater 

that was originally equipped with a catalytic combustor if the catalytic element is 

deactivated or removed.

(g) No person is permitted to operate, sell or offer for sale an affected wood heater 

that has been physically altered to exceed the tolerance limits of its certificate of 

compliance, pursuant to § 60.533(k).

(h) No person is permitted to alter, deface, or remove any permanent label 

required to be affixed pursuant to §§ 60.536(a) through (e), as applicable.

(i) If a temporary label is affixed to the wood heater, retailers may not sell or offer 

for sale that wood heater unless the temporary label affixed is in accordance with § 

60.536(f), as applicable.

§ 60.539 What hearing and appeal procedures apply to me?

(a)(1) The affected manufacturer, laboratory or third-party certifier may request a 

hearing under this section within 30 days following receipt of the required notification in 

any case where the Administrator—

(i) Denies an application for a certificate of compliance under § 60.533(c) or § 

60.533(f);

(ii) Denies an application for a renewal of certification under § 60.533(i);

(iii) Issues a notice of revocation of certification under § 60.533(1);

(iv) Denies an application for laboratory approval under § 60.535(a);
Page 174 of 326

(v) Issues a notice of revocation of laboratory approval under § 60.535(b);

(vi) Denies an application for third-party certifier approval under § 60.535(d); or

(vii) Issues a notice of revocation of third-party certifier approval under § 

60.535(e).

(2) In any case where the Administrator issues a notice of revocation under § 

60.533(n)(3)(ii), the manufacturer may request a hearing under this section with the time 

limits set out in § 60.533(n)(3)(ii). 

(b) Any hearing request must be in writing, must be signed by an authorized 

representative of the petitioning manufacturer or laboratory and must include a statement 

setting forth with particularity the petitioner's objection to the Administrator's 

determination or proposed determination.

(c)(l) Upon receipt of a request for a hearing under paragraph (a) of this section, 

the Administrator will request the Chief Administrative Law Judge to designate an 

Administrative Law Judge as Presiding Officer for the hearing. If the Chief 

Administrative Law Judge replies that no Administrative Law Judge is available to 

perform this function, the Administrator will designate a Presiding Officer who has not 

had any prior responsibility for the matter under review, and who is not subject to the 

direct control or supervision of someone who has had such responsibility.

(2) The hearing will commence as soon as practicable at a time and place fixed by 

the Presiding Officer.

(3)(i) A motion for leave to intervene in any proceeding conducted under this 

section must set forth the grounds for the proposed intervention, the position and interest 

of the movant and the likely impact that intervention will have on the expeditious 
Page 175 of 326

progress of the proceeding. Any person already a party to the proceeding may file an 

answer to a motion to intervene, making specific reference to the factors set forth in the 

foregoing sentence and paragraph (c)(3)(iii) of this section, within 10 days after service 

of the motion for leave to intervene.

(ii) A motion for leave to intervene in a proceeding must ordinarily be filed before 

the first prehearing conference or, in the absence of a prehearing conference, prior to the 

setting of a time and place for a hearing. Any motion filed after that time must include, in 

addition to the information set forth in paragraph (c)(3)(i) of this section, a statement of 

good cause for the failure to file in a timely manner. The intervener shall be bound by any 

agreements, arrangements and other matters previously made in the proceeding.

(iii) A motion for leave to intervene may be granted only if the movant 

demonstrates that his presence in the proceeding would not unduly prolong or otherwise 

prejudice the adjudication of the rights of the original parties, and that movant may be 

adversely affected by a final order. The intervener will become a full party to the 

proceeding upon the granting of leave to intervene.

(iv) Persons not parties to the proceeding may move for leave to file amicus 

curiae briefs. The movant must state his interest and the reasons why the proposed 

amicus brief is desirable. If the motion is granted, the Presiding Officer or Administrator 

will issue an order setting the time for filing such brief. An amicus curia may participate 

in any briefing after his motion is granted, and will be served with all briefs, reply briefs, 

motions and orders relating to issues to be briefed.

(4) In computing any period of time prescribed or allowed in this subpart, the day 

of the event from which the designated period begins to run will not be included. 
Page 176 of 326

Saturdays, Sundays and federal legal holidays will be included. When a stated time 

expires on a Saturday, Sunday or legal holiday, the stated time period will be extended to 

include the next business day.

(d)(l) Upon his appointment, the Presiding Officer must establish a hearing file. 

The file will consist of the notice issued by the Administrator under §§ 60.533(c)(2), 

60.533(f)(3), 60.533(i)(4), 60.533(l)(2), 60.533(n)(3)(ii)(A), 60.535(a)(3), 60.535(b)(2), 

60.535(d)(3) or 60.535(e)(2) together with any accompanying material, the request for a 

hearing and the supporting data submitted therewith, and all documents relating to the 

request for certification or approval or the proposed revocation of either.

(2) The hearing file must be available for inspection by any party, to the extent 

authorized by law, at the office of the Presiding Officer, or other place designated by him.

(e) Any party may appear in person, or may be represented by counsel or by any 

other duly authorized representative.

(f)(l) The Presiding Officer upon the request of any party, or at his discretion, may 

order a prehearing conference at a time and place specified by him to consider the 

following:

(i) Simplification of the issues,

(ii) Stipulations, admissions of fact, and the introduction of documents,

(iii) Limitation of the number of expert witnesses,

(iv) Possibility of agreement disposing of all or any of the issues in dispute,

(v) Such other matters as may aid in the disposition of the hearing, including such 

additional tests as may be agreed upon by the parties.
Page 177 of 326

(2) The results of the conference must be reduced to writing by the Presiding 

Officer and made part of the record.

(g)(l) Hearings will be conducted by the Presiding Officer in an informal but 

orderly and expeditious manner. The parties may offer oral or written evidence, subject to 

the exclusion by the Presiding Officer of irrelevant, immaterial and repetitious evidence.

(2) Witnesses will not be required to testify under oath. However, the Presiding 

Officer will call to the attention of witnesses that their statements may be subject to 

penalties under title 18 U.S.C. 1001 for knowingly making false statements or 

representations or using false documents in any matter within the jurisdiction of any 

department or agency of the United States.

(3) Any witness may be examined or cross-examined by the Presiding Officer, the 

parties or their representatives.

(4) Hearings must be recorded verbatim. Copies of transcripts of proceedings may 

be purchased by the applicant from the reporter.

(5) All written statements, charts, tabulations and similar data offered in evidence 

at the hearings must, upon a showing satisfactory to the Presiding Officer of their 

authenticity, relevancy and materiality, be received in evidence and will constitute a part 

of the record.

(h)(l) The Presiding Officer will make an initial decision which must include 

written findings and conclusions and the reasons or basis therefor on all the material 

issues of fact, law or discretion presented on the record. The findings, conclusions and 

written decision must be provided to the parties and made a part of the record. The initial 

decision will become the decision of the Administrator without further proceedings 
Page 178 of 326

unless there is an appeal to the Administrator or motion for review by the Administrator. 

Except as provided in paragraph (h)(3) of this section, any such appeal must be taken 

within 20 days of the date the initial decision was filed.

(2) On appeal from or review of the initial decision, the Administrator will have 

all the powers which he would have in making the initial decision including the discretion 

to require or allow briefs, oral argument, the taking of additional evidence or the 

remanding to the Presiding Officer for additional proceedings. The decision by the 

Administrator must include written findings and conclusions and the reasons or basis 

therefor on all the material issues of fact, law or discretion presented on the appeal or 

considered in the review.

(3) In any hearing requested under paragraph (a)(2) of this section the Presiding 

Officer must render the initial decision within 60 days of that request. Any appeal to the 

Administrator must be taken within 10 days of the initial decision, and the Administrator 

must render a decision in that appeal within 30 days of the filing of the appeal.

§ 60.539a Who implements and enforces this subpart?

(a) Under section 111(c) of the Clean Air Act, the Administrator may delegate the 

following implementation and enforcement authority to a state, local or tribal authority 

upon request:

(1) Enforcement of prohibitions on the installation and operation of affected wood 

heaters in a manner inconsistent with the installation and owner’s manual;

(2) Enforcement of prohibitions on operation of catalytic wood heaters where the 

catalyst has been deactivated or removed;
Page 179 of 326

(3) Enforcement of prohibitions on advertisement and/or sale of uncertified model

lines;

(4) Enforcement of prohibitions on advertisement and/or sale of affected heaters 

that do not have required permanent label;

(5) Enforcement of proper labeling of affected wood heaters; and

(6) Enforcement of compliance with other labeling requirements for affected 

wood heaters.

(7) Enforcement of certification testing procedures;

(8) Enforcement of requirements for sealing of the tested heaters and meeting 

parameter limits; and

(9) Enforcement of compliance requirements of EPA-approved laboratories. 

(b) Delegations shall not include:

(1) Decisions on certification;

(2) Revocation of certification;

(3) Establishment or revision of standards;

(4) Establishment or revision of test methods;

(5) Laboratory and third-party certifier approvals and revocations;

(6) Enforcing provisions governing content of owner’s manuals; and

(7) Hearings and appeals procedures.

(c) Nothing in these delegations will prohibit the Administrator from enforcing 

any applicable requirements.
Page 180 of 326

(d) Nothing in these delegations will limit delegated entities from using their 

authority under section 116 of the Clean Air Act to adopt or enforce more restrictive 

requirements.

§ 60.539b What parts of the General Provisions do not apply to me?

The following provisions of subpart A of part 60 do not apply to this subpart:

(a) Section 60.7;

(b) Section 60.8(a), (c), (d), (e), (f) and (g);

(c) Section 60.14; and

(c) Section 60.15(d).

4. Part 60 is amended by adding subpart QQQQ to read as follows:

Subpart QQQQ – Standards of Performance for New Residential Hydronic Heaters 

and Forced-Air Furnaces

Sec.

60.5472 Am I subject to this subpart?

60.5473 What definitions must I know?

60.5474 What standards and requirements must I meet and by when?

60.5475 What compliance and certification requirements must I meet and by when?

60.5476 What test methods and procedures must I use to determine compliance with the 

standards and requirements for certification?

60.5477 What procedures must I use for EPA approval of a test laboratory or EPA 

approval of a third-party certifier?

60.5478 What requirements must I meet for permanent labels, temporary labels 

(hangtags), and owner's manuals?
Page 181 of 326

60.5479 What records must I keep and what reports must I submit?

60.5480 What activities are prohibited under this subpart?

60.5481 What hearing and appeal procedures apply to me?

60.5482 Who implements and enforces this subpart?

60.5483 What parts of the General Provisions do not apply to me?

Subpart QQQQ – Standards of Performance for New Residential Hydronic Heaters 

and Forced-Air Furnaces

§ 60.5472 Am I subject to this subpart?

(a) You are subject to this subpart if you manufacture, sell, offer for sale, import 

for sale, distribute, offer to distribute, introduce or deliver for introduction into commerce 

in the United States, or install or operate a residential hydronic heater, forced-air furnace

or other central heater manufactured on or after [INSERT DATE 60 DAYS AFTER 

DATE OF PUBLICATION IN THE FEDERAL REGISTER], except as provided in 

paragraph (c) of this section.

(b) Each residential hydronic heater, forced-air furnace or other central heater

must comply with the provisions of this subpart unless exempted under paragraphs (b)(1) 

through (b)(3) of this section. These exemptions are determined by rule applicability and 

do not require additional EPA notification or public notice.

(1) Affected residential hydronic heaters, forced-air furnaces or other central 

heaters manufactured in the United States for export are exempt from the applicable 

emission limits of § 60.5474 and the requirements of § 60.5475.

(2) Affected residential hydronic heaters, forced-air furnaces or other central 

heaters used for research and development purposes that are never offered for sale or sold 
Page 182 of 326

and that are not used to provide heat are exempt from the applicable emission limits of § 

60.5474 and the requirements of § 60.5475. No more than 12 affected residential central 

heaters manufactured per model line may be exempted for this purpose.

(3) Appliances that do not burn wood or wood pellets or wood chips (such as 

coal-only central heaters that meet the definition in § 60.5473 or corn-only central 

heaters) are exempt from the applicable emission limits of § 60.5474 and the 

requirements of § 60.5475 provided that all advertising and warranties clearly denote that 

wood burning is prohibited in these appliances. 

(c) The following are not affected central heaters and are not subject to this 

subpart: 

(1) Residential wood heaters subject to subpart AAA of this part.

(2) Residential masonry heaters as defined in § 60.5473.

§ 60.5473 What definitions must I know?

As used in this subpart, all terms not defined herein have the same meaning given 

them in the Clean Air Act and subpart A of this part.

Approved test laboratory means a test laboratory that is approved for central

heater certification testing under § 60.5477 or is an independent third-party test 

laboratory that is accredited under ISO-IEC Standard 17025 to perform testing using the 

test methods specified in § 60.5476 by an accreditation body that is a full member 

signatory to the International Laboratory Accreditation Cooperation Mutual Recognition 

Arrangement and approved by the EPA for conducting testing under this subpart.

Catalytic combustor means a device coated with a noble metal used in a wood 

heater to lower the temperature required for combustion.
Page 183 of 326

Central heater means a fuel-burning device designed to burn wood or wood pellet 

fuel that warms spaces other than the space where the device is located, by the 

distribution of air heated by the furnace through ducts or liquid heated in the device and 

distributed typically through pipes. Unless otherwise specified, these devices include, but 

are not limited to, residential forced-air furnaces (small and large) and residential 

hydronic heaters.

Chip wood fuel means wood chipped into small pieces that are uniform in size, 

shape, moisture, density and energy content. 

Coal-only hydronic heater or forced-air furnace means an enclosed, coal-burning 

appliance capable of space heating or domestic water heating that has all of the following 

characteristics:

(1) Installation instructions, owner’s manual and marketing information that state 

that the use of wood in the appliance, except for coal ignition purposes, is prohibited by 

law; and

(2) The model is listed by a nationally recognized safety-testing laboratory for 

coal use only, except for coal ignition purposes.

Commercial owner means any person who owns or controls a residential hydronic 

heater, forced-air furnace or other affected central heater in the course of the business of 

the manufacture, importation, distribution, or sale of the unit.

Large residential forced-air furnace means a residential forced-air furnace that is 

capable of a heat output of 65,000 BTU per hour or greater. 

Manufactured means completed and ready for shipment (whether or not 

assembled or packaged) for purposes of determining the date of manufacture.
Page 184 of 326

Manufacturer means any entity that constructs or imports into the United States a 

central heater.

Model line means all central heaters offered for sale by a single manufacturer that 

are similar in all material respects that would affect emissions as defined in this section. 

Particulate matter (PM) means total particulate matter including coarse 

particulate (PM10) and fine particulate (PM2.5).

Pellet fuel means refined and densified solid wood shaped into small pellets or 

briquettes that are uniform in size, shape, moisture, density and energy content. 

Representative affected wood or central heater means an individual heater that is 

similar in all material respects that would affect emissions as defined in this section to 

other heaters within the model line it represents.

Residential forced-air furnace means a fuel burning device designed to burn 

wood or wood pellet fuel that warms spaces other than the space where the furnace is 

located, by the distribution of air heated by the furnace through ducts. 

Residential hydronic heater means a fuel burning device designed to burn wood 

or wood pellet fuel for the purpose of heating building space and/or water through the 

distribution, typically through pipes, of a fluid heated in the device, typically water or a 

water and antifreeze mixture.

Residential masonry heater means a factory-built or site-built wood-burning 

device in which the heat from intermittent fires burned rapidly in the firebox is stored in 

the refractory mass for slow release to building spaces. Masonry heaters are site-built

(using local materials or a combination of local materials and manufactured components) 

or site-assembled (using factory-built components), solid fuel-burning heating appliances 
Page 185 of 326

constructed mainly of refractory materials (e.g., masonry materials or soapstone. They 

typically have an interior construction consisting of a firebox and heat exchange channels 

built from refractory components, through which flue gases are routed. ASTM E-1602 

“Standard Guide for Construction of Solid Fuel Burning Masonry Heaters” provides 

design and construction information for the range of masonry heaters most commonly 

built in the United States. The site-assembled models are generally listed to UL-1482.

Sale means the transfer of ownership or control, except that a transfer of control 

of an affected central heater for research and development purposes within the scope of § 

60.5472(b)(2) is not a sale.

Similar in all material respects that would affect emissions means that the 

construction materials, exhaust and inlet air system, and other design features are within 

the allowed tolerances for components identified in § 60. 5475(k).

Small residential forced-air furnace means a residential forced-air furnace that is 

only capable of a maximum heat output of less than 65,000 BTU per hour. 

Sold at retail means the sale by a commercial owner of a central heater to the 

ultimate purchaser/user or noncommercial purchaser.

Third-party certifier (sometimes called third-party certifying body or product 

certifying body) means an independent third party that is accredited under ISO-IEC 

Standards 17025 and 17065 to perform certifications, inspections and audits by an 

accreditation body that is a full member signatory to the International Laboratory 

Accreditation Cooperation Mutual Recognition Arrangement and approved by the EPA 

for conducting certifications, inspections and audits under this subpart.
Page 186 of 326

Unseasoned wood means wood with an average moisture content of 20 percent or 

more.

Valid certification test means a test that meets the following criteria:

(1) The Administrator was notified about the test in accordance with § 60.5476(f);

(2) The test was conducted by an approved test laboratory as defined in this 

section;

(3) The test was conducted on a central heater similar in all material respects that 

would affect emissions as defined in this section to other central heaters of the model line 

that is to be certified; and 

(4) The test was conducted in accordance with the test methods and procedures 

specified in § 60.5476.

Wood heater under this subpart means an enclosed, wood burning-appliance 

capable of and intended for residential central heating or central heating and domestic 

water heating. Unless otherwise specified, these devices include, but are not limited to, 

hydronic heaters and forced-air furnaces.

§ 60.5474 What standards and requirements must I meet and by when?

(a) Standards. Unless exempted under § 60.5472, no person is permitted to:

(1) On or after [INSERT DATE 60 DAYS AFTER DATE OF PUBLICATION 

IN THE FEDERAL REGISTER], manufacture a residential hydronic heater unless it 

has been certified to meet the 2015 particulate matter emission limits in paragraph (b)(1) 

of this section. On or after December 31, 2015, no person is permitted to sell at retail a 

residential hydronic heater unless it has been certified to meet the 2015 particulate matter 

emission limits in paragraph (b)(1) of this section.
Page 187 of 326

(2) On or after [INSERT DATE 60 DAYS PLUS 5 YEARS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER] manufacture or sell at retail a 

residential hydronic heater unless it has been certified to meet the 2020 particulate matter 

emission limit in paragraph (b)(2) or (b)(3) of this section. 

(3) On or after [INSERT DATE 60 DAYS AFTER DATE OF PUBLICATION 

IN THE FEDERAL REGISTER], manufacture or sell at retail a residential forced-air 

furnace unless it complies with the work practice and operating standards in paragraphs 

(d), (e), (f) and (g) of this section and the owner’s manual requirements in Appendix I.

(4) On or after [INSERT DATE 60 DAYS PLUS 1 YEAR AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER], manufacture or sell at retail a 

small residential forced-air furnace unless it has been certified to meet the 2016

particulate matter emission limits in paragraph (b)(4) of this section

(5) On or after [INSERT DATE 60 DAYS PLUS 2 YEARS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER] manufacture or sell at retail a large 

forced-air furnace unless it has been certified to meet the 2017 particulate matter 

emission limits in paragraph (b)(5) of this section. 

(6) On or after [INSERT DATE 60 DAYS PLUS 5 YEARS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER] manufacture or sell at retail a small 

or large residential forced-air furnace unless it has been certified to meet the 2020 

particulate matter emission limit in paragraph (b)(6) of this section. 

(b)(1) 2015 residential hydronic heater particulate matter emission limit: a 

weighted average of 0.32 lb/mmBtu (0.137 g/MJ) heat output and a maximum per 
Page 188 of 326

individual burn rate of 18.0 g/hr (0.041 lb/hr) as determined by the test methods and 

procedures in § 60.5476.

(2) 2020 residential hydronic heater particulate matter emission limit: 0.10 

lb/mmBtu (0.026 g/MJ) heat output per individual burn rate as determined by the crib 

wood test methods and procedures in § 60.5476.

(3) 2020 residential hydronic heater cord wood alternative compliance option for 

particulate matter emission limit: 0.15 lb/mmBtu (0.026 g/MJ) heat output per individual 

burn rate as determined by the cord wood test methods and procedures in § 60.5476 or 

cord wood test methods approved by the Administrator.

(4) 2016 small forced-air furnace particulate matter emission limit: a weighted

average of 0.93 lb/mmBtu (0.40 g/MJ) heat output as determined by the test methods and 

procedures in § 60.5476.

(5) 2017 large forced-air furnace particulate matter emission limit: 0.93 lb/mmBtu 

(0.40 g/MJ) heat output per individual burn rate as determined by the test methods and 

procedures in § 60.5476.

(6) 2020 forced-air furnace particulate matter emission limit: 0.15 lb/mmBtu 

(0.026 g/MJ) heat output per individual burn rate as determined by the cord wood test 

methods and procedures in § 60.5476 or cord wood test methods approved by the 

Administrator.

(c) [Reserved]

(d) Chip Wood Fuel Requirements. Operators of wood central heaters, including 

hydronic heaters and forced-air furnaces, that are certified to burn chip wood fuels may 
Page 189 of 326

only burn wood chips that have been specified in the owner’s manual. The chip wood 

fuel must meet the following minimum requirements: 

(1) Moisture content: less than 35 percent

(2) Inorganic fines: less than or equal to 1 percent;

(3) Chlorides: less than or equal to 300 parts per million by weight; 

(4) Ash content: no more than 2 percent;

(5) No demolition or construction waste; and

(6) Trace metals: less than 100 mg/kg.

(e) Pellet Fuel Requirements. Operators of wood central heaters, including 

outdoor residential hydronic heaters, indoor residential hydronic heaters, and residential 

forced-air furnaces, that are certified to burn pellet fuels may only burn pellets that have 

been graded under a licensing agreement with a third-party organization approved by the 

EPA. The Pellet Fuels Institute, ENplus and CANplus are initially deemed to be 

approved third-party organizations for this purpose, and additional organizations may 

apply to the Administrator for approval. The pellet fuel must meet the following 

minimum requirements as assured through a quality assurance program licensed by a 

third-party organization approved by the EPA:

(1) Density: consistent hardness and energy content with a minimum density of 38 

pounds/cubic foot; 

(2) Dimensions: maximum length of 1.5 inches and diameter between 0.230 and 

0.285 inches; 

(3) Inorganic fines: less than or equal to 1 percent;

(4) Chlorides: less than or equal to 300 parts per million by weight; and 
Page 190 of 326

(5) Ash content: no more than 2 percent.

(6) Contains no demolition or construction waste;

(7) Trace metals: less than 100 mg/kg; and

(8) None of the prohibited fuels in (f).

(f) Prohibited Fuel Types. No person is permitted to burn any of the following 

materials in an outdoor residential hydronic heater, indoor residential hydronic heater, 

residential forced-air furnace or other affected central heater:

(1) Residential or commercial garbage;

(2) Lawn clippings or yard waste;

(3) Materials containing rubber, including tires;

(4) Materials containing plastic;

(5) Waste petroleum products, paints or paint thinners, or asphalt products;

(6) Materials containing asbestos;

(7) Construction or demolition debris;

(8) Paper products; cardboard, plywood or particleboard. The prohibition against 

burning these materials does not prohibit the use of fire starters made from paper, 

cardboard, saw dust, wax and similar substances for the purpose of starting a fire in an 

affected central heater;

(9) Railroad ties or pressure treated lumber;

(10) Manure or animal remains; 

(11) Salt water driftwood or other or other previously salt water saturated 

materials;

(12) Unseasoned wood; 
Page 191 of 326

(13) Any materials that are not included in the warranty and owner’s manual for 

the subject heater or furnace; or

(14) Any materials that were not included in the certification tests for the subject 

heater or furnace.

(g) Operation of Affected Wood Heaters. A user must operate an outdoor 

residential hydronic heater, indoor residential hydronic heater, residential forced-air 

furnace or other affected central heater in a manner consistent with the owner’s manual. 

The owner’s manual must clearly specify that operation in a manner inconsistent with the 

owner’s manual would void the warranty.

(h) Temperature Sensor Requirement. An affected wood heater equipped with a 

catalytic combustor must be equipped with a temperature sensor that can monitor 

combustor gas stream temperatures within or immediately downstream [within 2.54 

centimeters (1 inch)] of the catalytic combustor surface.

§ 60.5475 What compliance and certification requirements must I meet and by 

when?

(a) Certification Requirement. (1) Each affected residential hydronic heater,

forced-air furnace and other central heater must be certified to be in compliance with the 

applicable emission standards and other requirements of this subpart. For each model line 

manufactured or sold by a single entity, e.g., company or manufacturer, compliance with 

applicable emission standards of § 60.5474 must be determined based on testing of 

representative affected central heaters within the model line. If one entity licenses a 

model line to another entity, each entity’s model line must be certified. If an entity 
Page 192 of 326

intends to change the name of the entity or the name of the model, the manufacturer must 

apply for a new certification 60 days before making the change.

(2) The manufacturer of each model line must submit the information required in 

paragraph (b) of this section and follow either the certification process in paragraphs (c) 

through (e) of this section (for forced-air furnaces) or the certification procedure specified 

in paragraph (f) of this section. 

(3) Models qualified as meeting the Phase 2 emission levels under the 2011 EPA 

hydronic heater partnership agreement are automatically deemed to have a certificate of 

compliance for the 2015 particulate matter emission standards and be valid until the 

effective date for the 2020 particulate matter emission standards. 

(4) Models certified by the New York State Department of Environment and 

Conservation to meet the emission levels in § 60.5474(b) are automatically deemed to 

have a certificate of compliance for the 2015 particulate matter emission standards and be 

valid until the effective date for the 2020 particulate matter emission standards.

(5) Models approved by the New York State Energy Research and Development 

Authority under the Renewable Heat New York (RHNY) Biomass Boiler Program are 

automatically deemed to have a certificate of compliance for the 2015 particulate matter 

emission standards and be valid until the effective date for the 2020 particulate matter 

emission standards provided that they comply with the thermal storage requirements in 

the RHNY program.

(6) Small forced-air furnace models that are certified under CSA B415.1-10, by 

an EPA approved third-party certifier, to meet the 2016 particulate matter emission level

will be automatically deemed to have a certificate of compliance for the 2016 particulate 
Page 193 of 326

matter emission standards and be valid until the effective date for the 2020 particulate 

matter emission standards.

(7) Large forced-air furnace models that are certified under CSA B415.1-10, by 

an EPA approved third-party certifier, to meet the 2017 particulate matter emission level 

will be automatically deemed to have a certificate of compliance for the 2017 particulate 

matter emission standards.

(b) Application for a Certificate of Compliance. Any manufacturer of an affected 

residential hydronic heater or forced-air furnace or other central heater must apply to the 

Administrator for a certificate of compliance for each model line. The application must 

be submitted to: WoodHeaterReports@epa.gov. The application must be signed by a 

responsible representative of the manufacturer or an authorized representative and must 

contain the following:

(1) The model name and/or design number. The model name and/or design 

number must clearly distinguish one model from another. The name and/or design 

number cannot include the EPA symbol or logo or name or derivatives such as “EPA.” 

(2) Engineering drawings and specifications of components that may affect 

emissions (including specifications for each component listed in paragraph (k) of this 

section). Manufacturers may use assembly or design drawings that have been prepared 

for other purposes, but must designate on the drawings the dimensions of each 

component listed in paragraph (k) of this section. Manufacturers must identify 

dimensions of components listed in paragraph (k)(2) of this section that are different from 

those specified in that paragraph, and show that such differences cannot reasonably be 

anticipated to cause central heaters in the model line to exceed the applicable emission 
Page 194 of 326

limits. The drawings must identify how the emission critical parts, such as air tubes and 

catalyst, can be readily inspected and replaced. 

(3) A statement whether the firebox or any firebox component (including the 

materials listed in paragraph (k)(3) of this section) will be composed of material different 

from the material used for the firebox or firebox component in the central heater on 

which certification testing was performed and a description of any such differences and 

demonstration that any such differences may not reasonably be anticipated to adversely 

affect emissions or efficiency.

(4) Clear identification of any claimed confidential business information (CBI). 

Submit such information under separate cover to the EPA CBI Office; Attn: Residential 

Wood Heater Compliance Program Lead, 1200 Pennsylvania Ave., NW, Washington, 

DC 20004. Note that all emissions data, including all information necessary to determine 

emission rates in the format of the standard, cannot be claimed as CBI.

(5) All documentation pertaining to a valid certification test, including the 

complete test report and, for all test runs: Raw data sheets, laboratory technician notes, 

calculations and test results. Documentation must include the items specified in the 

applicable test methods. Documentation must include discussion of each test run and its 

appropriateness and validity, and must include detailed discussion of all anomalies, 

whether all burn rate categories were achieved, any data not used in the calculations and, 

for any test runs not completed, the data collected during the test run and the reason(s) 

that the test run was not completed. The documentation must show that the burn rate for 

the low burn rate category is no greater than the rate that an operator can achieve in home 

use and no greater than is advertised by the manufacturer or retailer. The test report must 
Page 195 of 326

include a summary table that clearly presents the individual and overall emission rates, 

efficiencies and heat outputs. Submit the test report and all associated required 

information according to the procedures for electronic reporting specified in § 60.5479(f).

(6) A copy of the warranties for the model line, which must include a statement 

that the warranties are void if the unit is used to burn materials for which the unit is not 

certified by the EPA and void if not operated according to the owner’s manual.

(7) A statement that the manufacturer will conduct a quality assurance program 

for the model line that satisfies the requirements of paragraph (m) of this section.

(8) A statement describing how the tested unit was sealed by the laboratory after 

the completion of certification testing and asserting that such unit will be stored by the 

manufacturer in the sealed state until 5 years after the certification test.

(9) Statements that the central heater manufactured under this certificate will be—

(i) Similar in all material respects that would affect emissions as defined in this 

subpart to the central heater submitted for certification testing, and

(ii) Labeled as prescribed in § 60.5478.

(iii) Accompanied by an owner’s manual that meets the requirements in § 

60.5478. In addition, a copy of the owner’s manual must be submitted to the EPA and be 

available to the public on the manufacturer’s web site.

(10) A statement that the manufacturer has entered into contracts with an 

approved laboratory and an approved third-party certifier that satisfy the requirements of 

paragraph (f) of this section.
Page 196 of 326

(11) A statement that the approved laboratory and approved third-party certifier 

are allowed to submit information on behalf of the manufacturer, including any claimed 

to be CBI.

(12) A statement that the manufacturer will place a copy of the certification test 

report and summary on the manufacturer’s web site available to the public within 30 days 

after the Administrator issues a certificate of compliance.

(13) A statement of acknowledgment that the certificate of compliance cannot be 

transferred to another manufacturer or model line without written approval by the 

Administrator.

(14) A statement acknowledging that it is unlawful to sell, distribute, or offer to 

sell or distribute an affected wood heater without a valid certificate of compliance.

(15) Contact information for the responsible representative of the manufacturer 

and all authorized representatives, including name, affiliation, physical address, 

telephone number and email address.

(c) Administrator Approval Process. (1) The Administrator may issue a certificate 

of compliance for a model line if the Administrator determines, based on all information 

submitted by the applicant and any other relevant information available, that:

(i) A valid certification test demonstrates that the representative affected central 

heater complies with the applicable emission standards in § 60.5474;

(ii) Any tolerances or materials for components listed in paragraph (k)(2) or (3) of 

this section that are different from those specified in those paragraphs may not reasonably 

be anticipated to cause central heaters in the model line to exceed the applicable emission 

limits; and
Page 197 of 326

(iii) The requirements of paragraph (b) of this section have been met. 

(2) The Administrator will deny certification if the Administrator determines that 

the criteria in paragraph (c)(1) of this section have not been satisfied. Upon denying 

certification under this paragraph, the Administrator will give written notice to the 

manufacturer setting forth the basis for this determination.

(d) Level of Compliance Certification. The Administrator will issue the certificate

of compliance for the most stringent particulate matter emission standard that the tested 

representative central heater meets under § 60.5474.

(e) Conditional, Temporary Certificate of Compliance. A conditional, temporary 

certificate of compliance with the Step 1 PM emission standards may be granted by the 

Administrator until [INSERT DATE 60 DAYS PLUS 1 YEAR AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER] for small or large forced-air furnaces 

based on the manufacturer’s submittal of a complete certification application meeting all 

requirements in § 60.5474(b). The application must include the full test report by an 

EPA-approved laboratory and all required compliance statements by the manufacturer

with the exception of a certificate of conformity by an EPA approved third-party certifier. 

The conditional, temporary approval would allow early marketing of forced-air furnaces 

as having a conditional, temporary certificate of compliance with the Step 1 PM emission 

standards until [INSERT DATE 60 DAYS PLUS 1 YEAR AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER] or until the Administrator 

completes the review of the application, whichever is earlier.

(f) Third-Party Certifier-Based Application Process. 
Page 198 of 326

(1) Any manufacturer of an affected central heater must apply to the 

Administrator for a certificate of compliance for each model line. The manufacturer must 

meet the following requirements: 

(i) The manufacturer must contract with a third-party certifier for certification 

services. The contract must include regular (at least annual) unannounced audits under 

ISO-IEC Standard 17065 to ensure that the manufacturer’s quality assurance plan is 

being implemented. The contract must also include a report for each audit under ISO-IEC 

Standard 17065 that fully documents the results of the audit. The contract must include

authorization and requirement for the third-party certifier to submit all such reports to the 

Administrator and the manufacturer within 30 days of the audit. The audit report must 

identify deviations from the manufacturer’s quality assurance plan and specify the

corrective actions that need to be taken to address each identified deficiency.

(ii) The manufacturer must submit the materials specified in paragraph (b) of this 

section and a quality assurance plan that meets the requirements of paragraph (m) of this 

section to the third-party certifier. The quality assurance plan must ensure that units 

within a model line will be similar in all material respects that would affect emissions to 

the wood heater submitted for certification testing, and it must include design drawings 

for the model line.

(iii) The manufacturer must apply to the third-party certifier for a certification of 

conformity with the applicable requirements of this subpart for the model line.

(A) After testing by an approved test laboratory is complete, certification of 

conformity with the emission standards in § 60.5474 must be performed by the 

manufacturer’s contracted third-party certifier. 
Page 199 of 326

(B) The third-party certifier may certify conformity if the emission tests have 

been conducted per the appropriate guidelines: the test report is complete and accurate;

the instrumentation used for the test was properly calibrated; the test report shows that the

representative affected central heater meets the applicable emission limits specified in § 

60.5474; and the quality assurance plan is adequate to ensure that units within the model 

line will be similar in all material respects that would affect emissions to the central 

heater submitted for certification testing, and that the affected heaters would meet all 

applicable requirements of this subpart. 

(iv) The manufacturer must then submit to the Administrator an application for a 

certificate of compliance that includes the certification of conformity, quality assurance

plan, test report and all supporting documentation specified in paragraph (b) of this 

section.

(v) The submission also must include a statement signed by a responsible official 

of the manufacturer or authorized representative that the manufacturer has complied with 

and will continue to comply with all requirements of this subpart for certificate of 

compliance and that the manufacturer remains responsible for compliance regardless of 

any error by the test laboratory or third-party certifier.

(2) The Administrator will issue to the manufacturer a certificate of compliance 

for a model line if it is determined, based on all of the information submitted in the 

application for certification and any other relevant information, that:

(i) A valid certification of conformity has demonstrated that the representative 

affected central heater complies with the applicable emission standards in § 60.5474; 
Page 200 of 326

(ii) Any tolerances or materials for components listed in paragraph (k)(2) or (3) of 

this section that are different from those specified in those paragraphs may not be 

reasonably anticipated to cause central heaters in the model line to exceed the applicable 

emission limits;

(iii) The requirements of paragraphs (b) of this section have been met; and

(iv) A valid certificate of conformity for the model line has been prepared and 

submitted.

(3) The Administrator will deny certification if the Administrator determines that 

the criteria in paragraph (f)(2) of this section have not been satisfied. Upon denying 

certification under this paragraph, the Administrator will give written notice to the 

manufacturer setting forth the basis for the determination. 

(g) Waiver from Submitting Test Results. An applicant for certification may apply 

for a potential waiver of the requirement to submit the results of a certification test 

pursuant to paragraph (b) of this section, if the central heater meets either of the 

following conditions:

(1) The central heaters of the model line are similar in all material respects that 

would affect emissions, as defined in § 60.5473 and paragraph (k) of this section, to 

another model line that has already been issued a certificate of compliance. A 

manufacturer that seeks a waiver of certification testing must identify the model line that 

has been certified, and must submit a copy of an agreement with the owner of the design 

permitting the applicant to produce central heaters of that design.
Page 201 of 326

(2) The manufacturer has previously conducted a valid certification test to 

demonstrate that the central heaters of the model line meet the applicable standard 

specified in § 60.5474. 

(h) Certification Period. Unless revoked sooner by the Administrator, a 

certificate of compliance will be valid for 5 years from the date of issuance or until a 

more stringent standard comes into effect, whichever is sooner.

(i) Renewal of Certification.

(1) The manufacturer must renew a model line’s certificate of compliance or 

recertify the model line every 5 years, or the manufacturer may choose to no longer 

manufacture or sell that model line after the expiration date. If the manufacturer chooses 

to no longer manufacture that model line, then the manufacturer must submit a statement 

to the Administrator to that effect.

(2) A manufacturer of an affected residential hydronic heater or forced-air furnace 

or other central heater may apply to the Administrator for potential renewal of its

certificate of compliance by submitting the material specified in paragraph (b) and 

following the procedures specified in paragraph (f), or by affirming in writing that the 

central heaters in the model line continue to be similar in all material respects that would 

affect emissions to the representative central heater submitted for testing on which the 

original certificate of compliance was based and requesting a potential waiver from 

certification testing. The application must include a copy of the review of the draft 

application and approval by the third-party certifier.
Page 202 of 326

(3) If the Administrator grants a renewal of certification, the Administrator will 

give written notice to the manufacturer setting forth the basis for the determination and 

issue a certification renewal.

(4) If the Administrator denies the request for a renewal of certification, the 

Administrator will give written notice to the manufacturer setting forth the basis for the 

determination.

(5) If the Administrator denies the request for a renewal of certification, the 

manufacturer and retailer must not manufacture or sell the previously-certified central 

heaters after the expiration date of the certificate of compliance.

(j) [Reserved]

(k) Recertification. 

(1) The manufacturer must recertify a model line whenever any change is made in 

the design submitted pursuant to paragraph (k)(2) of this section that affects or is 

presumed to affect the particulate matter emission rate for that model line. The 

manufacturer of an affected central heater must apply to the Administrator for potential 

recertification by submitting the material specified in paragraph (b) of this section and 

following the procedures specified in paragraph (f) of this section or by affirming in 

writing that the change will not cause the central heaters in the model line to exceed 

applicable emission limits and requesting a waiver from certification testing. The 

application for recertification must be reviewed and approved by the contracted thirdparty certifier and a copy of the review and approval must be included. The 

Administrator may waive this requirement upon written request by the manufacturer, if 

the manufacturer presents adequate rationale and the Administrator determines that the 
Page 203 of 326

change may not reasonably be anticipated to cause central heaters in the model line to 

exceed the applicable emission limits. The granting of such a waiver does not relieve the 

manufacturer of any compliance obligations under this subpart.

(2) Any change in the design tolerances of any of the following components 

(where such components are applicable) is presumed to affect particulate matter and 

carbon monoxide emissions and efficiency if that change exceeds ±0.64 cm (±1/4 inch) 

for any linear dimension and ±5 percent for any cross-sectional area relating to air 

introduction systems and catalyst bypass gaps unless other dimensions and crosssectional areas are previously approved by the Administrator under paragraph (c)(1)(ii) of 

this section:

(i) Firebox: Dimensions;

(ii) Air introduction systems: Cross-sectional area of restrictive air inlets and 

outlets, location and method of control;

(iii) Baffles: Dimensions and locations;

(iv) Refractory/insulation: Dimensions and location;

(v) Catalyst: Dimensions and location;

(vi) Catalyst bypass mechanism and catalyst bypass gap tolerances (when bypass 

mechanism is in closed position): Dimensions, cross-sectional area, and location;

(vii) Flue gas exit: Dimensions and location;

(viii) Door and catalyst bypass gaskets: Dimensions and fit;

(ix) Outer thermal shielding and thermal coverings: Dimensions and location;

(x) Fuel feed system: For central heaters that are designed primarily to burn wood 

pellet fuel or wood chips and other central heaters equipped with a fuel feed system, the 
Page 204 of 326

fuel feed rate, auger motor design and power rating, and the angle of the auger to the 

firebox; and

(xi) Forced air combustion system: For central heaters so equipped, the location 

and horsepower of blower motors and the fan blade size.

(3) Any change in the materials used for the following components is presumed to 

affect particulate matter emissions and efficiency:

(i) Refractory/insulation; or

(ii) Door and catalyst bypass gaskets.

(4) A change in the make, model, or composition of a catalyst is presumed to 

affect particulate matter and carbon monoxide emissions and efficiency, unless the 

change has been requested by the central heater manufacturer and has been approved in 

advance by the Administrator, based on test data that demonstrate that the replacement 

catalyst is equivalent to or better than the original catalyst in terms of particulate matter 

emission reduction.

(l) Criteria for Revocation of Certification. 

(1) The Administrator may revoke certification of a product line if it is 

determined that the central heaters being manufactured or sold in that model line do not 

comply with the requirements of this subpart. Such a determination will be based on all 

available evidence, including but not limited to:

(i) Test data from retesting of the original unit on which the certification test was 

conducted on a unit that is similar in all material respects that would affect emissions;
Page 205 of 326

(ii) A finding that the certification test was not valid. The finding will be based on 

problems or irregularities with the certification test or its documentation, but may be 

supplemented by other information;

(iii) A finding that the labeling of the central heater model line or the owner’s 

manual or the associated marketing information does not comply with the requirements 

of § 60.5478;

(iv) Failure by the manufacturer to comply with the reporting and recordkeeping 

requirements of § 60.5479;

(v) Physical examination showing that a significant percentage (as defined in the 

quality assurance plan approved pursuant to paragraph (m) of this section, but no larger 

than 1 percent) of production units inspected is not similar in all material respects that 

would affect emissions to the representative affected central heater submitted for 

certification testing; or

(vi) Failure of the manufacturer to conduct a quality assurance program in 

conformity with paragraph (m) of this section.

(vii) Failure of the approved laboratory to test the central heater using the 

methods specified in § 60.5476.

(2) Revocation of certification under this paragraph (l) will not take effect until 

the manufacturer concerned has been given written notice by the Administrator setting 

forth the basis for the proposed determination and an opportunity to request a hearing

under § 60.5481.

(m) Quality Assurance Program. 
Page 206 of 326

On or after [INSERT DATE 60 DAYS PLUS 1 YEAR AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER], for each certified model line, the 

manufacturer must conduct a quality assurance program that satisfies the requirements of 

paragraphs (m)(1) through (5) of this section. 

(1) The manufacturer must prepare and operate according to a quality assurance 

plan for each certified model line that includes specific inspection and testing 

requirements for ensuring that all units within a model line are similar in all material 

respects that would affect emissions to the central heater submitted for certification 

testing and meet the emissions standards in § 60.5474.

(2) The quality assurance plan must be approved by the third-party certifier as 

part of the certification of conformity process specified in paragraph (f) of this section.

(3) The quality assurance plan must include regular (at least annual) unannounced 

audits by the third-party certifier under ISO-IEC Standard 17065 to ensure that the 

manufacturer’s quality assurance plan is being implemented. 

(4) The quality assurance plan must include a report for each audit under ISO-IEC 

Standard 17065 that fully documents the results of the audit. The third-party certifier 

must be authorized and required to submit all such reports to the Administrator within 30 

days of the audit. The audit report must identify deviations from the manufacturer’s 

quality assurance plan and specify the corrective actions that need to be taken to address 

each identified deficiency. 

(5) Within 30 days after receiving each audit report, the manufacturer must report 

to the third-party certifier and to the Administrator its corrective actions and responses to 
Page 207 of 326

any deficiencies identified in the audit report. No such report is required if an audit report 

did not identify any deficiencies.

(n) EPA Compliance Audit Testing. 

(1)(i) The Administrator may select by written notice central heaters or model 

lines for compliance audit testing to determine compliance with the emission standards in 

§ 60.5474. 

(ii) The Administrator will transmit a written notification of the selected central 

heaters or model line(s) to the manufacturer, which will include the name and address of 

the laboratory selected to perform the audit test and the model name and serial number of 

the central heater(s) or central heater model line(s) selected to undergo audit testing.

(2)(i) The Administrator may test, or direct the manufacturer to have tested, the 

central heater(s) from the model line(s) selected under paragraph (n)(1)(i) of this section 

in a laboratory approved under § 60.5477. The Administrator may select any approved 

test laboratory or federal laboratory for this audit testing.

(ii) The expense of the compliance audit test is the responsibility of the central 

heater manufacturer.

(iii) The test must be conducted using the same test method used to obtain 

certification. If the certification test consisted of more than one particulate matter 

sampling test method, the Administrator may direct the manufacturer and test laboratory 

as to which of these methods to use for the purpose of audit testing. The Administrator 

will notify the manufacturer at least 30 days prior to any test under this paragraph, and 

allow the manufacturer and/or his authorized representatives to observe the test.

(3) Revocation of Certification.
Page 208 of 326

(i) If emissions from a central heater tested under paragraph (n)(2) of this section 

exceed the applicable emission standard by more than 50 percent using the same test 

method used to obtain certification, the Administrator will notify the manufacturer that 

certification for that model line is suspended effective 72 hours from the receipt of the 

notice, unless the suspension notice is withdrawn by the Administrator. The suspension 

will remain in effect until withdrawn by the Administrator, or the date 30 days from its 

effective date if a revocation notice under paragraph (n)(3)(ii) of this section is not issued 

within that period, or the date of final agency action on revocation, whichever occurs 

earliest.

(ii)(A) If emissions from a central heater tested under paragraph (n)(2) of this 

section exceed the applicable emission limit, the Administrator will notify the 

manufacturer that certification is revoked for that model line.

(B) A notice under paragraph (n)(3)(ii)(A) of this section will become final and 

effective 60 days after the date of written notification to the manufacturer, unless it is 

withdrawn, a hearing is requested under § 60.5481(a)(2), or the deadline for requesting a 

hearing is extended.

(C) The Administrator may extend the deadline for requesting a hearing for up to 

60 days for good cause.

(D) A manufacturer may extend the deadline for requesting a hearing for up to 6 

months, by agreeing to a voluntary suspension of certification.

(iii) Any notification under paragraph (n)(3)(i) or (n)(3)(ii) of this section will 

include a copy of a preliminary test report from the approved test laboratory or federal 

test laboratory. The test laboratory must provide a preliminary test report to the 
Page 209 of 326

Administrator within 14 days of the completion of testing, if a central heater exceeds the 

applicable emission limit in § 60.5474. The test laboratory must provide the 

Administrator and the manufacturer, within 30 days of the completion of testing, all 

documentation pertaining to the test, including the complete test report and raw data 

sheets, laboratory technician notes, and test results for all test runs.

(iv) Upon receiving notification of a test failure under paragraph (n)(3)(ii) of this 

section, the manufacturer may request that up to four additional central heaters from the 

same model line be tested at the manufacturer’s expense, at the test laboratory that 

performed the emissions test for the Administrator.

(v) Whether or not the manufacturer proceeds under paragraph (n)(3)(iv) of this 

section, the manufacturer may submit any relevant information to the Administrator, 

including any other test data generated pursuant to this subpart. The manufacturer must 

bear the expense of any additional testing.

(vi) The Administrator will withdraw any notice issued under paragraph (n)(3)(ii) 

of this section if tests under paragraph (n)(3)(iv) of this section show either—

(A) That exactly four additional central heaters were tested for the manufacturer 

and all four met the applicable emission limits; or

(B) That exactly two additional central heaters were tested for the manufacturer 

and each of them met the applicable emission limits and the average emissions of all 

three tested heaters (the original audit heater and the two additional heaters) met the 

applicable emission limits.

(vii) If the Administrator withdraws a notice pursuant to paragraph (n)(3)(vi) of 

this section, the Administrator will revise the certification values for the model line based 
Page 210 of 326

on the test data and other relevant information. The manufacturer must then revise the 

labels and marketing information accordingly.

(viii) The Administrator may withdraw any proposed revocation, if the 

Administrator finds that an audit test failure has been rebutted by information submitted 

by the manufacturer under paragraph (n)(3)(iv) of this section and/or (n)(3)(v) of this 

section or by any other relevant information available to the Administrator.

§ 60.5476 What test methods and procedures must I use to determine compliance 

with the standards and requirements for certification?

Test methods and procedures specified in this section or in appendices of this part, 

except as provided under § 60.8(b), must be used to determine compliance with the 

standards and requirements for certification under § § 60.5474 and 60.5475 and for 

reporting carbon monoxide emissions and efficiency. The EPA will post all approved 

alternative test methods on the EPA web site. The manufacturer or the manufacturer’s 

authorized representative must submit a summary and the full test report with all 

supporting information, including detailed discussion of all anomalies, whether all burn 

rate categories were properly achieved, any data not used in the calculations and, for any 

test runs not completed, the data that were collected and the reason that the test run was 

not completed. The burn rate for the low burn rate category must be no greater than the 

rate that an operator can achieve in home use and no greater than is advertised by the 

manufacturer or retailer.

(a) Canadian Standards Administration (CSA) Method B415.1-10, sections 13.7-

13.10, must be used to measure the thermal efficiency and CO emissions of outdoor and 
Page 211 of 326

indoor residential hydronic heaters and forced-air furnaces, except that the burn rates 

specified in Method 28 WHH must be used for hydronic heaters.

(b) Testing conducted with continuously fed biomass as the fuel(s) must be 

conducted according to the relevant section of the ASTM E2618-13 or adaptations 

approved by EPA. The EPA will post all approved alternative test methods on the EPA 

web site. 

(c)(1) For outdoor and indoor residential hydronic heaters to be tested under the 

2015 particulate matter emission standards in § 60.5474(b)(1), the manufacturer must 

have an EPA-approved test laboratory use:

(i) Method 28 WHH;

(ii) Method 28 WHH PTS;

(iii) ASTM E2618-13 (using crib wood); or

(iv) EN 303-5, only for units sold with thermal storage. 

(2) For outdoor and indoor residential hydronic heaters to be tested under the 

2020 particulate matter emission standards in § 60.5474(b)(2), the manufacturer must 

have an EPA-approved test laboratory use:

(i) Method 28 WHH;

(ii) Method 28 WHH PTS; or 

(iii) ASTM E2618-13 (using crib wood). 

(3) If the heater is equipped with full or partial heat storage, the manufacturer, 

retailer and installer must not sell or install the heater with less heat storage capacity than 

is used in the certification test.
Page 212 of 326

(4) The manufacturer and approved laboratory must make the following 

adjustments to the methods listed in (a), (c)(1) and (2) of this section:

(i) For ASTM E2618-13, the burn rate categories specified in Method 28 WHH 

must be used;

(ii) For EN 303-5, the organic compounds must be included as part of the PM.

(iii) For ASTM 2618-13 Appendix A1 for full thermal storage certification tests, 

the test must use the large scale as required in the test method unless the manufacturer 

requests a variance, in advance of testing, contingent upon measuring flue gas 

temperature, oxygen and CO, using a simple electronic spreadsheet calculator to estimate 

efficiency and conducting a comparison to the delivered efficiency to determine if a more 

detailed examination should be made.

(5) For particulate matter emission concentrations measured with ASTM E2515-

11, four-inch filters and Teflon membrane filters or Teflon-coated glass fiber filters may 

be used.

(6) For all tests conducted using ASTM 2515-11 pursuant to this section, the 

manufacturer and approved test laboratory must also measure the first hour of particulate 

matter emissions for each test run using a separate filter in one of the two parallel trains. 

The manufacturer and approved test laboratory must report the test results for the first 

hour separately and also include them in the total particulate matter emissions per run.

(d)(1) For hydronic heaters subject to the 2020 cord wood alternative compliance 

option specified in § 60.5474(b)(3), the manufacturers must have the approved laboratory 

conduct cord wood testing using the test methods listed below:

(i) Method 28 WHH;
Page 213 of 326

(ii) Method 28 WHH PTS; or

(iii) ASTM E2618-13 (using cord wood). 

(2) If the heater is equipped with full or partial heat storage, the manufacturer, 

retailer and installer must not sell or install the heater with less heat storage capacity than 

is used in the certification test.

(3) The manufacturer and approved laboratory must make the following 

adjustments to the methods listed in (d)(1) of this section: 

(i) For ASTM E2618-13, use the burn rate categories specified in Method 28 

WHH;

(ii) For all methods, report the results separately per burn rate category.

(e) For forced-air furnaces, use CSA Method B415.1-10 to measure the heat 

output (mmBtu/hr) and particulate matter emission rate (lb/mmBtu heat output), except 

use the burn rate categories in Method 28WHH for the 2020 particulate matter emission 

standards. For the 2020 particulate matter emission standards, report the particulate 

material, efficiency and CO emission results separately per burn rate category.

(f) For affected wood heaters subject to the particulate matter emission standards, 

emission concentrations must be measured with ASTM E2515-11, except for the 2015

certification tests using EN303-5. As required in paragraph (c)(4)(ii) of this section, the 

manufacturer and approved laboratory must add the organic gases to the PM for EN 303-

5. Four-inch filters and Teflon membrane filters or Teflon-coated glass fiber filters may 

be used in ASTM E2515-11. Method 5H is not allowed for certification testing.

(g) Douglas fir may be used in ASTM E2618-13 and CSA B415.1-10.
Page 214 of 326

(h) The manufacturer of an affected central heater model line must notify the 

Administrator of the date that certification testing is to begin, by email, to 

WoodHeaterReports@epa.gov. This notice must be at least 30 days before the start of 

testing. The notification of testing must include the manufacturer’s name and physical 

and email addresses, the approved test laboratory’s name and physical and email 

addresses, third-party certifier name, the model name and number (or, if unavailable, 

some other way to distinguish between models), and the dates of testing. The laboratory 

may substitute certification testing of another affected central heater on the original date 

in order to ensure regular laboratory testing operations.

(i) The approved test laboratory must allow the manufacturer, the manufacturer’s 

approved third-party certifier, the EPA and delegated state regulatory agencies to observe 

certification testing. However, manufacturers must not involve themselves in the conduct 

of the test after the pretest burn has begun. Communications between the manufacturer 

and laboratory or third-party certifier personnel regarding operation of the central heater 

must be limited to written communications transmitted prior to the first pretest burn of 

the certification series. During certification tests, the manufacturer may communicate 

with laboratory personnel only in writing and only to notify them that the manufacturer 

has observed a deviation from proper test procedures. All communications must be 

included in the test documentation required to be submitted pursuant to § 60.5475(b)(5) 

and must be consistent with instructions provided in the owner's manual required under § 

60.5478(f), except to the extent that they address details of the certification tests that 

would not be relevant to owners or regulators.
Page 215 of 326

§ 60.5477 What procedures must I use for EPA approval of a test laboratory or EPA 

approval of a third-party certifier?

(a) Test Laboratory Approval. (1) A laboratory must apply to the Administrator 

for approval to test under this rule by submitting documentation that the laboratory is 

accredited by a nationally recognized accrediting entity under ISO-IEC Standard 17025 

to perform testing using the test methods specified under § 60.5476. Laboratories 

accredited by EPA prior to [INSERT DATE 60 DAYS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER] may have until [INSERT DATE 3 

YEARS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER] to 

submit documentation that they have accreditation under ISO-IEC Standard 17025 to 

perform testing using the test methods specified under § 60.5476. ISO accreditation is 

required for all other laboratories performing testing beginning on [INSERT DATE 60 

DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].

(2) As part of the application, the test laboratory must:

(i) Agree to participate biennially in an independently operated proficiency testing 

program with no direct ties to the laboratories participating;

(ii) Agree to allow the Administrator, regulatory agencies and certifying bodies 

access to observe certification testing;

(iii) Agree to comply with calibration, reporting and recordkeeping requirements 

that affect testing laboratories; and

(iv) Agree to perform a compliance audit test at the manufacturer’s expense at the 

testing cost normally charged to such manufacturer if the laboratory is selected by the 

Administrator to conduct the compliance audit test of the manufacturer’s model line. The 
Page 216 of 326

test laboratory must provide a preliminary audit test report to the Administrator within 14 

days of the completion of testing, if a central heater exceeds the applicable emission limit 

in § 60.5474. The test laboratory must provide the Administrator and the manufacturer, 

within 30 days of the completion of audit testing, all documentation pertaining to the test, 

including the complete test report and raw data sheets, laboratory technician notes, and 

test results for all test runs.

(v) Have no conflict of interest and receive no financial benefit from the outcome 

of certification testing conducted pursuant to § 60.5475.

(vi) Agree to not perform initial certification tests on any models manufactured by 

a manufacturer for which the laboratory has conducted research and development design 

services within the last 5 years.

(vii) Agree to seal any wood heater on which it performed certification tests, 

immediately upon completion or suspension of certification testing, by using a 

laboratory-specific seal.

(viii) Agree to immediately notify the Administrator of any suspended tests 

through email and in writing, giving the date suspended, the reason(s) why, and the 

projected date for restarting. The laboratory must submit the operation and test data 

obtained, even if the test is not completed. 

(3) If the EPA approves the laboratory, the Administrator will provide the test 

laboratory with a certificate of approval for testing under this rule. If the EPA does not 

approve the laboratory, the Administrator will give written notice to the laboratory setting 

forth the basis for the determination.
Page 217 of 326

(b) Revocation of Test Laboratory Approval. (1) The Administrator may revoke 

the EPA laboratory approval if it is determined that the laboratory:

(i) Is no longer accredited by the accreditation body;

(ii) Does not follow required procedures or practices;

(iii) Has falsified data or otherwise misrepresented emission data;

(iv) Failed to participate in a proficiency testing program, in accordance with its 

commitment under paragraph (a)(2)(ii) of this section; or

(v) Failed to seal the central heater in accordance with paragraph (a)(2)(vii) of this 

section.

(2) Revocation of approval under this paragraph (b) will not take effect until the 

laboratory concerned has been given written notice by the Administrator setting forth the 

basis for the proposed determination and an opportunity for a hearing under § 60.5481. 

However, if revocation is ultimately upheld, all tests conducted by the laboratory after 

written notice was given will, at the discretion of the Administrator, be declared invalid.

(c) Period of Test Laboratory Approval. (1) With the exception of laboratories 

meeting the provisions of paragraph (c)(2) of this section, and unless revoked sooner, a 

certificate of approval for testing under this rule is valid for 5 years from the date of 

issuance..

(2) Laboratories accredited by the EPA by [INSERT DATE 60 DAYS AFTER 

DATE OF PUBLICATION IN THE FEDERAL REGISTER], under the provisions of 

§ 60.535 as in effect prior to that date may continue to be EPA accredited and deemed 

EPA approved for testing under this subpart until [INSERT DATE 60 DAYS PLUS 3 

YEARS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER], at 
Page 218 of 326

which time the EPA accreditation and approval ends unless the laboratory has obtained 

accreditation under § 60.5477 as in effect on that date.

(d) Third-Party Certifier Approval

(1) A Third-party certifier may apply to the Administrator for approval to be an 

EPA-approved third-party certifier by submitting credentials demonstrating that it has 

been accredited by a nationally recognized accrediting entity to perform certifications and 

inspections under ISO-IEC Standard 17025, ISO-IEC Standard 17065 and ISO-IEC 

Standard 17020.

(2) As part of the application, the third-party certifier must:

(i) Agree to offer to contract with central heater manufacturers to perform thirdparty certification activities according to the requirements set out in this subpart.

(ii) Agree to periodically conduct audits as described in § 60.5475(m) and the 

manufacturer’s quality assurance program; 

(iii) Agree to comply with reporting and recordkeeping requirements that affect 

approved central heater testing laboratories and third-party certifiers;

(iv) Have no conflict of interest and receive no financial benefit from the outcome 

of certification testing conducted pursuant to § 60.5475; 

(v) Agree to make available to the Administrator supporting documentation for 

each central heater certification and audit; and

(vi) Agree to not perform initial certification reviews on any models 

manufactured by a manufacturer for which the third-party certifier has conducted 

research and development design services within the last 5 years.
Page 219 of 326

(3) If approved, the Administrator will provide the third-party certifier with a 

certificate of approval. The approval will expire 5 years after being issued unless renewed 

by the third-party certifier. If the EPA denies the approval, the Administrator will give 

written notice to the third-party certifier for the basis for the determination.

(e) Revocation of Third-Party Certifier Approval. (1) The Administrator will 

revoke the third-party certifier’s EPA approval if it is determined that the certifier:

(i) Is no longer accredited by the accreditation body;

(ii) Does not follow required procedures or practices; or

(iii) Has falsified certification data or otherwise misrepresented emission data.

(2) Revocation of approval under this paragraph (f) will not take effect until the 

certifier concerned is given written notice by the Administrator setting forth the basis for 

the proposed determination and an opportunity for a hearing under § 60.5481. However, 

if revocation is upheld, all certifications by the certifier after written notice was given 

will, at the discretion of the Administrator, be declared invalid.

§ 60.5478 What requirements must I meet for permanent labels, temporary labels 

(hangtags), and owner's manuals?

(a) General Permanent Label Requirements.

(1) Each affected central heater manufactured or sold on or after the date the 

applicable standards come into effect as specified in § 60.5474, must have a permanent 

label affixed to it that meets the requirements of this section.

(2) The permanent label must contain the following information:

(i) Month and year of manufacture of the individual unit;

(ii) Model name and number;
Page 220 of 326

(iii) Certification test emission value, test method, and standard met; and

(iv) Serial number.

(3) The permanent label must:

(i) Be affixed in a readily visible or accessible location in such a manner that it 

can be easily viewed before and after the appliance is installed (a easily removable façade 

can be used for aesthetic purposes);

(ii) Be at least 8.9 cm long and 5.1 cm wide (3 1/2 inches long and 2 inches wide);

(iii) Be made of a material expected to last the lifetime of the central heater;

(iv) Present the required information in a manner so that it is likely to remain 

legible for the lifetime of the central heater; and

(v) Be affixed in such a manner that it cannot be removed without damage to the 

label.

(4) The permanent label may be combined with any other label, as long as the 

required information is displayed, the integrity of the permanent label is not 

compromised, and the permanent label meets the requirements of § 60.5478(a)(3).

(5) Any label statement under paragraph (b) of this section constitutes a 

representation by the manufacturer as to any central heater that bears it:

(i) That a certification of compliance was in effect at the time the central heater

left the possession of the manufacturer;

(ii) That the manufacturer was, at the time the label was affixed, conducting a 

quality assurance program in conformity with § 60.5475(m); and
Page 221 of 326

(iii) That all the central heaters individually tested for emissions by the 

manufacturer under its quality assurance program pursuant to § 60.5475(m) met the 

applicable emissions limit.

(b) Permanent Label Requirements for Central Heaters. If a central heater

belongs to a model line certified under § 60.5475, and no unit in the model line has been 

found to exceed the applicable emission limits or tolerances through quality assurance 

testing, one of the following statements, as appropriate, must appear on the permanent 

label:

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Certified to comply with the 2015 particulate emission standards.

Not approved for sale after [INSERT DATE 60 DAYS PLUS 5 YEARS AFTER 

DATE OF PUBLICATION IN THE FEDERAL REGISTER]”

or

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Certified to comply with the 2016 particulate emission standards.

Not approved for sale after [INSERT DATE 60 DAYS PLUS 5 YEARS AFTER 

DATE OF PUBLICATION IN THE FEDERAL REGISTER]”

or

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Certified to comply with the 2017 particulate emission standards.

Not approved for sale after [INSERT DATE 60 DAYS PLUS 5 YEARS AFTER 

DATE OF PUBLICATION IN THE FEDERAL REGISTER]”

or
Page 222 of 326

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Certified to comply with the 2020 particulate emission standards using crib wood.”

or

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Certified to comply with the 2020 particulate emission standards using cord wood.”

(c) Additional Permanent Label Content. The permanent label for all certified 

central heaters must also contain the following statement on the permanent label:

“This appliance needs periodic inspection and repair for proper operation. Consult 

owner's manual for further information. It is against federal regulations to operate this 

appliance in a manner inconsistent with operating instructions in the owner's manual.”

(d) Permanent Label Requirements for Affected Wood Heaters with Exemptions 

under § 60.5472(b).

(1) If an affected central heater is manufactured in the United States for export as 

provided in § 60.5472(b)(1), the following statement must appear on the permanent label:

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Export appliance. May not be sold or operated in the United States.”

(2) If an affected central heater is manufactured for use for research and 

development purposes as provided in § 60.5472(b)(2), the following statement must 

appear on the permanent label:

“U.S. ENVIRONMENTAL PROTECTION AGENCY

Not certified. Research Appliance. Not approved for sale or for operation other than for 

research.”
Page 223 of 326

(3) If an affected central heater is a non wood-burning central heater exclusively 

as provided in § 60.5472(b)(3), the following statement must appear on the permanent 

label:

“U.S. ENVIRONMENTAL PROTECTION AGENCY

This appliance is not certified for wood burning. Use of any wood fuel is a violation of 

federal regulations.”

(e) Temporary Label (Hangtag) Voluntary Options.

(1) Each model line certified to meet the 2020 particulate emission standards prior 

to [INSERT DATE 60 DAYS PLUS 5 YEARS AFTER DATE OF PUBLICATION 

IN THE FEDERAL REGISTER] may display the hangtags specified in section 3 of 

Appendix I of this part. The electronic template will be provided by the Administrator 

upon approval of the certification.

(2) The hangtags in (e)(1) of this section end upon [INSERT DATE 60 DAYS 5 

YEARS AFTER DATE OF PUBLICATION IN THE FEDERAL REGISTER].

(3) Each model certified to meet the 2020 Cord Wood Alternative Compliance 

Option may display the cord wood temporary label specified in section 3 of Appendix I

of this part. The electronic template will be provided by the Administrator upon approval 

of the certification.

(f) Owner’s Manual Requirements(1) Each affected central heater offered for sale 

by a commercial owner must be accompanied by an owner's manual that must contain the 

information listed in paragraph (f)(2) of this section (pertaining to installation), and 

paragraph (f)(3) of this section (pertaining to operation and maintenance). Such 

information must be adequate to enable consumers to achieve optimal emissions 
Page 224 of 326

performance. Such information must be consistent with the operating instructions 

provided by the manufacturer to the approved test laboratory for operating the central 

heater during certification testing, except for details of the certification test that would not 

be relevant to the ultimate user. The commercial owner must also make current and 

historical owner’s manuals available on the company web site and upon request to the 

EPA.

(2) Guidance on proper installation information, including stack height, heater 

location and achieving proper draft.

(3) Proper operation and maintenance information, including minimizing visible 

emissions.

(i) Fuel loading and re-loading procedures, recommendations on fuel selection 

and warnings on what fuels not to use, such as unseasoned wood, treated wood, colored 

paper, cardboard, solvents, trash and garbage.

(ii) Fire starting procedures

(iii) Proper use of air controls, including how to establish good combustion and 

how to ensure good combustion at the lowest burn rate for which the heater is warranted;

(iv) Ash removal procedures

(v) Instructions for replacement of gaskets and other parts that are critical to the 

emissions performance of the unit and other maintenance and repair instructions; 

(vi) For catalytic models, information on the following pertaining to the catalytic 

combustor: Procedures for achieving and maintaining catalyst activity, maintenance 

procedures, procedures for determining deterioration or failure, procedures for 

replacement and information on how to exercise warranty rights; 
Page 225 of 326

(vii) For catalytic models, the following statement—

“This wood heater contains a catalytic combustor, which needs periodic inspection and 

replacement for proper operation. It is against federal regulations to operate this wood 

heater in a manner inconsistent with operating instructions in this manual, or if the 

catalytic element is deactivated or removed.”; and

(viii) For noncatalytic models, the following statement—

“This wood heater needs periodic inspection and repair for proper operation. It is against 

federal regulations to operate this wood heater in a manner inconsistent with operating 

instructions in this manual.”

(4) Any manufacturer using the EPA-recommended language contained in 

Appendix I of this part to satisfy any requirement of this paragraph (f) will be considered 

to be in compliance with that requirement, provided that the particular model language is 

printed in full, with only such changes as are necessary to ensure accuracy for the 

particular model line.

(g) Central heaters that are affected by this subpart, but that have been owned and 

operated by a noncommercial owner, are not subject to paragraphs (e) and (f) of this

section when offered for resale.

§ 60.5479 What records must I keep and what reports must I submit?

(a)(1)Each manufacturer who holds a certificate of compliance pursuant to § 

60.5475(a)(2) for a model line must maintain records containing the information required 

by paragraph (a)(2) through (4) of this section with respect to that model line for at least 

5 years.
Page 226 of 326

(2) All documentation pertaining to the certification test used to obtain 

certification, including the full test report and raw data sheets, laboratory technician 

notes, calculations, and the test results for all test runs, and discussions of the 

appropriateness and validity of all test runs, including runs attempted but not completed. 

The retained certification test documentation must include, as applicable, detailed 

discussions of all anomalies, whether all burn rate categories were properly achieved, any 

data not used in the calculations and, for any test runs not completed, the data that were 

collected and the reason that the test run was not completed. The retained certification 

test also must include documentation that the burn rate for the low burn category was no 

greater than the rate that an operator can achieve in home use and no greater than is 

advertised by the manufacturer or retailer.

(3) Results of the quality assurance program inspections required pursuant to § 

60.5475(m).

(4) For emissions tests conducted pursuant to the quality assurance program 

required by § 60.5475(m), all test reports, data sheets, laboratory technician notes, 

calculations, and test results for all test runs, the corrective actions taken, if any, and any 

follow-up actions such as additional testing.

(b) Each approved test laboratory and third-party certifier must maintain records 

consisting of all documentation pertaining to each certification test, quality assurance 

program inspection and audit test, including the full test report and raw data sheets, 

technician notes, calculations, the test results for all test runs. Each approved test 

laboratory must submit accreditation credentials and all proficiency test results to the 

Administrator. Each third-party certifier must submit each certification test, quality 
Page 227 of 326

assurance program inspection report and ISO-IEC accreditation credentials to the 

Administrator.

(c) Each manufacturer must retain each central heater upon which certification 

tests were performed and certification granted under § 60.5475(a)(2) at the 

manufacturer’s facility for 5 years after the certification test. Each central heater must 

remain sealed and unaltered. Any such central heater must be made available upon 

request to the Administrator for inspection and testing.

(d) Each manufacturer of an affected central heater model line certified pursuant 

to § 60.5475(a)(2) must submit a report to the Administrator every 2 years following 

issuance of a certificate of compliance for each model line. This report must include the 

sales for each model by state and certify that no changes in the design or manufacture of 

the model line have been made that require recertification pursuant to § 60.5475(k).

(e)(1) Unless otherwise specified, all records required under this section must be 

maintained by the manufacturer, commercial owner of the affected central heater, 

approved test laboratory or third-party certifier for a period of no less than 5 years.

(2) Unless otherwise specified, all reports to the Administrator required under this 

subpart must be made to: WoodHeaterReports@epa.gov.

(f) Within 60 days after the date of completing each performance test (e.g., initial 

certification test, tests conducted for quality assurance and tests for renewal or 

recertification), each manufacturer must submit performance test data electronically to 

WoodHeaterReports@epa.gov. Owners or operators who claim that some of the 

information being submitted for performance tests is CBI (e.g., design drawings) must 

submit a complete file, including information claimed to be CBI on a compact disk or 
Page 228 of 326

other commonly used electronic storage media (including, but not limited to, flash 

drives), by mail, and the same file with the CBI omitted, electronically. The compact disk 

must be clearly marked as CBI and mailed to U.S. EPA, OECA CBI Office, Attention: 

Residential Wood Heater Compliance Program, Washington, D.C. 20004. Emission data 

and all information necessary to determine compliance, except sensitive engineering 

drawings and sensitive detailed material specifications, cannot be claimed as CBI.

(g) Within 30 days of receiving a certification of compliance for a model line, the 

manufacturer must make the full non-CBI test report and the summary of the test report 

available on the manufacturer’s web site.

(h) Each manufacturer who uses the exemption for R&D heaters under § 

60.5472(b)(2) must maintain records for at least 5 years documenting where the heaters 

were located, that the heaters were never offered for sale or sold and that the heaters were 

not used for the purpose of heating.

§ 60.5480 What activities are prohibited under this subpart?

(a) No person is permitted to advertise for sale, offer for sale, sell or operate an 

affected residential hydronic heater or forced-air furnace or other central heater that does 

not have affixed to it a permanent label pursuant to § 60.5478(b) through (d), as 

applicable.

(b) No person is permitted to advertise for sale, offer for sale, or sell an affected 

central heater labeled under § 60.5478(d)(1) except for export. No person is permitted to 

operate an affected central heater in the United States if it is labeled under § 

60.5478(d)(1). 
Page 229 of 326

(c)(1) No commercial owner is permitted to advertise for sale, offer for sale, or 

sell an affected central heater permanently labeled under § 60.5478(b) unless:

(i) The affected appliance has been certified to comply with the particulate 

emission standards pursuant to § 60.5474 as applicable; and

(ii) The commercial owner provides any purchaser or transferee with an owner's 

manual that meets the requirements of § 60.5478(f), a copy of the warranty and a 

moisture meter.

(2) A commercial owner other than a manufacturer complies with the 

requirements of paragraph (c)(1) of this section if the commercial owner:

(i) Receives the required documentation from the manufacturer or a previous 

commercial owner; and

(ii) Provides that documentation unaltered to any person to whom the central 

heater that it covers is sold or transferred.

(d)(1) In any case in which the Administrator revokes a certificate of compliance 

either for the knowing submission of false or inaccurate information or other fraudulent 

acts, or based on a finding under § 60.5475(l)(1)(ii) that the certification test was not 

valid, the Administrator may give notice of that revocation and the grounds for it to all 

commercial owners.

(2) On and after the date of receipt of the notice given under paragraph (d)(1) of 

this section, no commercial owner is permitted to sell any central heater covered by the 

revoked certificate (other than to the manufacturer) unless the model line has been 

recertified in accordance with this subpart.
Page 230 of 326

(e) No person is permitted to install or operate an affected central heater except in 

a manner consistent with the instructions on its permanent label and in the owner's 

manual pursuant to § 60.5478(f), including only using fuels for which the unit is certified.

(f) No person is permitted to operate, sell or offer for sale an affected central

heater that was originally equipped with a catalytic combustor if the catalytic element is 

deactivated or removed.

(g) No person is permitted to operate, sell or offer for sale an affected central 

heater that has been physically altered to exceed the tolerance limits of its certificate of 

compliance, pursuant to§ 60.5475(k).

(i) No person is permitted to alter, deface, or remove any permanent label 

required to be affixed pursuant to § 60.5478(a) through (d), as applicable.

(i) If a temporary label is affixed to the central heater, retailers may not sell or 

offer for sale that central heater unless the temporary label affixed is in accordance with § 

60.5478(e), as applicable.

§ 60.5481 What hearing and appeal procedures apply to me?

(a)(1) The affected manufacturer, laboratory or third-party certifier may request a 

hearing under this section within 30 days following receipt of the required notification in 

any case where the Administrator—

(i) Denies an application for a certificate of compliance under § 60.5475 (a)(2);

(ii) Denies an application for a renewal of certification under § 60.5475(i);

(iii) Issues a notice of revocation of certification under § 60.5475(l); (iv) Denies 

an application for laboratory approval under § 60.5477(a);

(v) Issues a notice of revocation of laboratory approval under § 60.5477(b).

(vi) Denies an application for third-party certifier approval under § 60.5477(d); or
Page 231 of 326

(vii) Issues a notice of revocation of third-party certifier approval under § 

60.5477(e).

(2) In any case where the Administrator issues a notice of revocation under § 

60.5475(n)(3)(ii),, the manufacturer may request a hearing under this section with the 

time limits set out in § 60.5475(n)(3)(ii). 

(b) Any hearing request must be in writing, must be signed by an authorized 

representative of the petitioning manufacturer or laboratory, and must include a statement 

setting forth with particularity the petitioner's objection to the Administrator's 

determination or proposed determination.

(c)(l) Upon receipt of a request for a hearing under paragraph (a) of this section, 

the Administrator will request the Chief Administrative Law Judge to designate an 

Administrative Law Judge as Presiding Officer for the hearing. If the Chief 

Administrative Law Judge replies that no Administrative Law Judge is available to 

perform this function, the Administrator will designate a Presiding Officer who has not 

had any prior responsibility for the matter under review, and who is not subject to the 

direct control or supervision of someone who has had such responsibility.

(2) The hearing will commence as soon as practicable at a time and place fixed by 

the Presiding Officer.

(3)(i) A motion for leave to intervene in any proceeding conducted under this 

section must set forth the grounds for the proposed intervention, the position and interest 

of the movant and the likely impact that intervention will have on the expeditious 

progress of the proceeding. Any person already a party to the proceeding may file an 

answer to a motion to intervene, making specific reference to the factors set forth in the 
Page 232 of 326

foregoing sentence and paragraph (c)(3)(iii) of this section within 10 days after service of 

the motion for leave to intervene.

(ii) A motion for leave to intervene in a proceeding must ordinarily be filed before 

the first prehearing conference or, in the absence of a prehearing conference, prior to the 

setting of a time and place for a hearing. Any motion filed after that time must include, in 

addition to the information set forth in paragraph (c)(3)(i) of this section, a statement of 

good cause for the failure to file in a timely manner. The intervener shall be bound by any 

agreements, arrangements and other matters previously made in the proceeding.

(iii) A motion for leave to intervene may be granted only if the movant 

demonstrates that his presence in the proceeding would not unduly prolong or otherwise 

prejudice the adjudication of the rights of the original parties, and that movant may be 

adversely affected by a final order. The intervener will become a full party to the 

proceeding upon the granting of leave to intervene.

(iv) Persons not parties to the proceeding may move for leave to file amicus 

curiae briefs. The movant must state his interest and the reasons why the proposed 

amicus brief is desirable. If the motion is granted, the Presiding Officer or Administrator 

will issue an order setting the time for filing such brief. An amicus curia may participate 

in any briefing after his motion is granted, and will be served with all briefs, reply briefs, 

motions, and orders relating to issues to be briefed.

(4) In computing any period of time prescribed or allowed in this subpart, the day 

of the event from which the designated period begins to run will not be included. 

Saturdays, Sundays, and federal legal holidays will be included. When a stated time 
Page 233 of 326

expires on a Saturday, Sunday or legal holiday, the stated time period will be extended to 

include the next business day.

(d)(l) Upon his appointment the Presiding Officer must establish a hearing file. 

The file will consist of the notice issued by the Administrator under §§ 60.5475(c)(2), 

60.5475(f)(3), 60.5475(i)(4), 60.5475(l)(2), 60.5475(n)(3)(ii)(A), 60.5477(a)(3), 

60.5477(b)(2), 60.5477(d)(3) or 60.5477(e)(2), together with any accompanying 

material, the request for a hearing and the supporting data submitted therewith, and all 

documents relating to the request for certification or approval, or the proposed revocation 

of either.

(2) The hearing file must be available for inspection by any party, to the extent 

authorized by law, at the office of the Presiding Officer, or other place designated by him.

(e) Any party may appear in person, or may be represented by counsel or by any 

other duly authorized representative.

(f)(l) The Presiding Officer, upon the request of any party, or at his discretion, 

may order a prehearing conference at a time and place specified by him to consider the 

following:

(i) Simplification of the issues;

(ii) Stipulations, admissions of fact, and the introduction of documents;

(iii) Limitation of the number of expert witnesses;

(iv) Possibility of agreement disposing of all or any of the issues in dispute; and

(v) Such other matters as may aid in the disposition of the hearing, including such

additional tests as may be agreed upon by the parties.
Page 234 of 326

(2) The results of the conference must be reduced to writing by the Presiding 

Officer and made part of the record.

(g)(l) Hearings shall be conducted by the Presiding Officer in an informal but 

orderly and expeditious manner. The parties may offer oral or written evidence, subject to 

the exclusion by the Presiding Officer of irrelevant, immaterial and repetitious evidence.

(2) Witnesses will not be required to testify under oath. However, the Presiding

Officer will call to the attention of witnesses that their statements may be subject to 

penalties under title 18 U.S.C. 1001 for knowingly making false statements or 

representations or using false documents in any matter within the jurisdiction of any 

department or agency of the United States.

(3) Any witness may be examined or cross-examined by the Presiding Officer, the 

parties, or their representatives.

(4) Hearings must be recorded verbatim. Copies of transcripts of proceedings may 

be purchased by the applicant from the reporter.

(5) All written statements, charts, tabulations and similar data offered in evidence 

at the hearings must, upon a showing satisfactory to the Presiding Officer of their 

authenticity, relevancy and materiality, be received in evidence and will constitute a part 

of the record.

(h)(l) The Presiding Officer will make an initial decision which must include 

written findings and conclusions and the reasons or basis therefor on all the material 

issues of fact, law, or discretion presented on the record. The findings, conclusions and 

written decision must be provided to the parties and made a part of the record. The initial 

decision will become the decision of the Administrator without further proceedings 
Page 235 of 326

unless there is an appeal to the Administrator or motion for review by the Administrator. 

Except as provided in paragraph (h)(3) of this section, any such appeal must be taken 

within 20 days of the date the initial decision was filed.

(2) On appeal from or review of the initial decision the Administrator will have all 

the powers which he would have in making the initial decision including the discretion to 

require or allow briefs, oral argument, the taking of additional evidence or the remanding 

to the Presiding Officer for additional proceedings. The decision by the Administrator 

must include written findings and conclusions and the reasons or basis therefor on all the 

material issues of fact, law, or discretion presented on the appeal or considered in the 

review.

(3) In any hearing requested under paragraph (a)(2) of this section the Presiding 

Officer must render the initial decision within 60 days of that request. Any appeal to the 

Administrator must be taken within 10 days of the initial decision, and the Administrator 

must render a decision in that appeal within 30 days of the filing of the appeal.

§ 60.5482 Who implements and enforces this subpart?

(a) Under section 111(c) of the Clean Air Act, the Administrator may delegate the 

following implementation and enforcement authority to a state, local or tribal authority 

upon request:

(1) Enforcement of prohibitions on the installation and operation of affected 

central heaters in a manner inconsistent with the installation and owner’s manual;

(2) Enforcement of prohibitions on operation of catalytic central heaters where the 

catalyst has been deactivated or removed;
Page 236 of 326

(3) Enforcement of prohibitions on advertisement and/or sale of uncertified model

lines;

(4) Enforcement of prohibitions on advertisement and/or sale of affected central 

heaters that do not have required permanent label;

(5) Enforcement of proper labeling of affected central heaters;

(6) Enforcement of compliance with other labeling requirements for affected 

central heaters.

(7) Enforcement of certification testing procedures;

(8) Enforcement of requirements for sealing of the tested central heaters and 

meeting parameter limits; and

(9) Enforcement of compliance requirements of EPA-approved laboratories. 

(b) Delegations shall not include:

(1) Decisions on certification;

(2) Revocation of certification;

(3) Establishment or revision of standards;

(4) Establishment or revision of test methods;

(5) Laboratory and third-party certifier approvals and revocations;

(6) Enforcing provisions governing content of owner’s manuals; and

(7) Hearings and appeals procedures.

(c) Nothing in these delegations will prohibit the Administrator from enforcing 

any applicable requirements.
Page 237 of 326

(d) Nothing in these delegations will limit delegated entities from using their 

authority under section 116 of the Clean Air Act to adopt or enforce more restrictive 

requirements.

§ 60.5483 What parts of the General Provisions do not apply to me?

The following provisions of subpart A of part 60 do not apply to this subpart:

(a) Section 60.7;

(b) Section 60.8(a), (c), (d), (e), (f) and (g); and

(c) Section 60.15(d).

5. Part 60 Appendix A-8 is amended by adding Method 28R to follow Method 

28A to read as follows:

Test Method 28R for Certification and Auditing of Wood Heaters

1.0 Scope and Application

1.1 This test method applies to certification and auditing of wood-fired room 

heaters and fireplace inserts.

1.2 The test method covers the fueling and operating protocol for measuring 

particulate emissions, as well as determining burn rates, heat output and efficiency.

1.3 Particulate emissions are measured by the dilution tunnel method as specified 

in ASTM E2515-11 Standard Test Method for Determination of Particulate Matter 

Emissions Collected in a Dilution Tunnel. Upon request, four-inch filters may be used. 

Upon request, Teflon membrane filters or Teflon-coated glass fiber filters may be used. 

2.0 Procedures

2.1 This method incorporates the provisions of ASTM E2780-10 except as 

follows:
Page 238 of 326

2.1.1 The burn rate categories, low burn rate requirement, and weightings in 

Method 28 shall be used.

2.1.2 The startup procedures shall be the same as in Method 28.

2.1.3 Manufacturers shall not specify a smaller volume of the firebox for testing 

than the full usable firebox.

2.1.4 Prior to testing, the heater must be operated for a minimum of 50 hours 

using a medium burn rate. The conditioning may be at the manufacturer’s facility prior to 

the certification test. If the conditioning is at the certification test laboratory, the pre-burn 

for the first test can be included as part of the conditioning requirement.

2.2 Manufacturers may use ASTM E871-82 (reapproved 2013) as an alternative 

to the procedures in Method 5H or Method 28 for determining total weight basis moisture 

in the analysis sample of particulate wood fuel.

6. Part 60 Appendix A-8 is amended by adding Method 28 WHH to follow 

Method 28R to read as follows:

Test Method 28 WHH for Measurement of Particulate Emissions and Heating 

Efficiency of Wood-Fired Hydronic Heating Appliances

1.0 Scope and Application

1.1 This test method applies to wood-fired hydronic heating appliances. The units 

typically transfer heat through circulation of a liquid heat exchange media such as water 

or a water-antifreeze mixture.

1.2 The test method measures particulate emissions and delivered heating 

efficiency at specified heat output rates based on the appliance’s rated heating capacity.
Page 239 of 326

1.3 Particulate emissions are measured by the dilution tunnel method as specified 

in ASTM E2515-11 Standard Test Method for Determination of Particulate Matter 

Emissions Collected in a Dilution Tunnel. Upon request, four-inch filters may be used. 

Upon request, Teflon membrane filters or Teflon-coated glass fiber filters may be used. 

Delivered efficiency is measured by determining the heat output through measurement of 

the flow rate and temperature change of water circulated through a heat exchanger 

external to the appliance and determining the input from the mass of dry wood fuel and 

its higher heating value. Delivered efficiency does not attempt to account for pipeline 

loss.

1.4 Products covered by this test method include both pressurized and nonpressurized heating appliances intended to be fired with wood. These products are woodfired hydronic heating appliances that the manufacturer specifies for indoor or outdoor 

installation. They are often connected to a heat exchanger by insulated pipes and 

normally include a pump to circulate heated liquid. They are used to heat structures such 

as homes, barns and greenhouses and can heat domestic hot water, spas or swimming 

pools.

1.5 Distinguishing features of products covered by this standard include:

1.5.1 Manufacturer specifies for indoor or outdoor installation.

1.5.2 A firebox with an access door for hand loading of fuel.

1.5.3 Typically, an aquastat that controls combustion air supply to maintain the 

liquid in the appliance within a predetermined temperature range provided sufficient fuel 

is available in the firebox.

1.5.4 A chimney or vent that exhausts combustion products from the appliance.
Page 240 of 326

1.6 The values stated are to be regarded as the standard whether in I-P or SI units. 

The values given in parentheses are for information only.

2.0 Summary of Method and References

2.1 Particulate matter emissions are measured from a wood-fired hydronic heating 

appliance burning a prepared test fuel crib in a test facility maintained at a set of 

prescribed conditions. Procedures for determining burn rates, and particulate emissions 

rates and for reducing data are provided.

2.2 Referenced Documents

2.2.1 EPA Standards

2.2.1.1 Method 28 Certification and Auditing of Wood Heaters

2.2.2 Other Standards

2.2.2.1 ASTM E2515-11 Standard Test Method for Determination of Particulate 

Matter Emissions Collected in a Dilution Tunnel.

2.2.2.2 CAN/CSA-B415.1-10 Performance Testing of Solid-Fuel-Burning 

Heating Appliances.

3.0 Terminology

3.1 Definitions

3.1.1 Hydronic Heating – A heating system in which a heat source supplies 

energy to a liquid heat exchange media such as water that is circulated to a heating load 

and returned to the heat source through pipes.

3.1.2 Aquastat – A control device that opens or closes a circuit to control the rate 

of fuel consumption in response to the temperature of the heating media in the heating 

appliance.
Page 241 of 326

3.1.3 Delivered Efficiency – The percentage of heat available in a test fuel charge 

that is delivered to a simulated heating load as specified in this test method. 

3.1.4 Manufacturer’s Rated Heat Output Capacity − The value in Btu/hr (MJ/hr) 

that the manufacturer specifies that a particular model of hydronic heating appliance is 

capable of supplying at its design capacity as verified by testing, in accordance with 

Section 13.

3.1.5 Burn Rate − The rate at which test fuel is consumed in an appliance. 

Measured in pounds (lbs) or kilograms of wood (dry basis) per hour (lb/hr or kg/hr).

3.1.6 Firebox − The chamber in the appliance in which the test fuel charge is 

placed and combusted.

3.1.7 Test Fuel Charge − The collection of test fuel layers placed in the appliance 

at the start of the emission test run.

3.1.8 Test Fuel Layer – Horizontal arrangement of test fuel units.

3.1.9 Test Fuel Unit − One or more test fuel pieces with 3⁄4 inch (19 mm) spacers 

attached to the bottom and to one side. If composed of multiple test fuel pieces, the 

bottom spacer may be one continuous piece.

3.1.10 Test Fuel Piece − A single 4 x 4 (4 ± 0.25 inches by 4 ± 0.25 inches)[100 ± 

6 mm by 100 ± 6 mm] white or red oak wood piece cut to the length required.

3.1.11 Test Run – An individual emission test that encompasses the time required 

to consume the mass of the test fuel charge.

3.1.12 Overall Efficiency (SLM) – The efficiency for each test run as determined 

using the CSA B415.1-10 stack loss method. 
Page 242 of 326

3.1.13 Thermopile - A device consisting of a number of thermocouples connected 

in series, used for measuring differential temperature.

4.0 Summary of Test Method

4.1 Dilution Tunnel. Emissions are determined using the “dilution tunnel” method 

specified in ASTM E2515-11 Standard Test Method for Determination of Particulate 

Matter Emissions Collected in a Dilution Tunnel. The flow rate in the dilution tunnel is 

maintained at a constant level throughout the test cycle and accurately measured. 

Samples of the dilution tunnel flow stream are extracted at a constant flow rate and drawn 

through high efficiency filters. The filters are dried and weighed before and after the test 

to determine the emissions catch and this value is multiplied by the ratio of tunnel flow to 

filter flow to determine the total particulate emissions produced in the test cycle.

4.2 Efficiency. The efficiency test procedure takes advantage of the fact that this 

type of appliance delivers heat through circulation of the heated liquid (water) from the 

appliance to a remote heat exchanger and back to the appliance. Measurements of the 

water temperature difference as it enters and exits the heat exchanger along with the 

measured flow rate allow for an accurate determination of the useful heat output of the 

appliance. The input is determined by weight of the test fuel charge, adjusted for moisture 

content, multiplied by the higher heating value. Additional measurements of the 

appliance weight and temperature at the beginning and end of a test cycle are used to 

correct for heat stored in the appliance. Overall efficiency (SLM) is determined using the 

CSA B415.1-10 stack loss method for data quality assurance purposes.

4.3 Operation. Appliance operation is conducted on a hot-to-hot test cycle 

meaning that the appliance is brought to operating temperature and a coal bed is 
Page 243 of 326

established prior to the addition of the test fuel charge and measurements are made for 

each test fuel charge cycle. The measurements are made under constant heat draw 

conditions within predetermined ranges. No attempt is made to modulate the heat demand 

to simulate an indoor thermostat cycling on and off in response to changes in the indoor 

environment. Four test categories are used. These are:

4.3.1 Category I: A heat output of 15 percent or less of manufacturer’s rated heat 

output capacity.

4.3.2 Category II: A heat output of 16 percent to 24 percent of manufacturer’s 

rated heat output capacity.

4.3.3 Category III: A heat output of 25 percent to 50 percent of manufacturer’s 

rated heat output capacity.

4.3.4 Category IV: Manufacturer’s rated heat output capacity.

5.0 Significance and Use

5.1 The measurement of particulate matter emission rates is an important test 

method widely used in the practice of air pollution control.

5.1.1 These measurements, when approved by state or federal agencies, are often 

required for the purpose of determining compliance with regulations and statutes.

5.1.2 The measurements made before and after design modifications are necessary 

to demonstrate the effectiveness of design changes in reducing emissions and make this 

standard an important tool in manufacturers’ research and development programs.

5.2 Measurement of heating efficiency provides a uniform basis for comparison of 

product performance that is useful to the consumer. It is also required to relate emissions 

produced to the useful heat production.
Page 244 of 326

5.3 This is a laboratory method and is not intended to be fully representative of all 

actual field use. It is recognized that users of hand-fired, wood-burning equipment have a 

great deal of influence over the performance of any wood-burning appliance. Some 

compromises in realism have been made in the interest of providing a reliable and 

repeatable test method.

6.0 Test Equipment

6.1 Scale. A platform scale capable of weighing the appliance under test and 

associated parts and accessories when completely filled with water to an accuracy of ±1.0 

pound (±0.5 kg).

6.2 Heat Exchanger. A water-to-water heat exchanger capable of dissipating the 

expected heat output from the system under test.

6.3 Water Temperature Difference Measurement. A Type – T ‘special limits’ 

thermopile with a minimum of 5 pairs of junctions shall be used to measure the 

temperature difference in water entering and leaving the heat exchanger. The temperature 

difference measurement uncertainty of this type of thermopile is equal to or less than ± 

0.50oF (± 0. 25oC). Other temperature measurement methods may be used if the 

temperature difference measurement uncertainty is equal to or less than ±0.50oF (± 0. 

25oC). 

6.4 Water Flow Meter. A water flow meter shall be installed in the inlet to the 

load side of the heat exchanger. The flow meter shall have an accuracy of ± 1 percent of 

measured flow. 
Page 245 of 326

6.4.1 Optional - Appliance Side Water Flow Meter. A water flow meter with an 

accuracy of ± 1 percent of the flow rate is recommended to monitor supply side water 

flow rate.

6.5 Optional Recirculation Pump. Circulating pump used during test to prevent 

stratification of liquid being heated.

6.6 Water Temperature Measurement – Thermocouples or other temperature 

sensors to measure the water temperature at the inlet and outlet of the load side of the 

heat exchanger. Must meet the calibration requirements specified in section 10.1.

6.7 Wood Moisture Meter - Calibrated electrical resistance meter capable of 

measuring test fuel moisture to within 1 percent moisture content. Must meet the 

calibration requirements specified in section10.4.

6.8 Flue Gas Temperature Measurement - Must meet the requirements of CSA 

B415.1-10, clause 6.2.2.

6.9 Test Room Temperature Measurement - Must meet the requirements of CSA 

B415.1-10, clause 6.2.1.

6.10 Flue Gas Composition Measurement - Must meet the requirements of CSA 

B415.1-10, clauses 6.3.1 through 6.3.3.

7.0 Safety

7.1 These tests involve combustion of wood fuel and substantial release of heat 

and products of combustion. The heating system also produces large quantities of very 

hot water and the potential for steam production and system pressurization. Appropriate 

precautions must be taken to protect personnel from burn hazards and respiration of 

products of combustion.
Page 246 of 326

8.0 Sampling, Test Specimens and Test Appliances

8.1 Test specimens shall be supplied as complete appliances including all controls 

and accessories necessary for installation in the test facility. A full set of specifications 

and design and assembly drawings shall be provided when the product is to be placed 

under certification of a third-party agency. The manufacturer’s written installation and 

operating instructions are to be used as a guide in the set-up and testing of the appliance.

9.0 Preparation of Test Equipment

9.1 The appliance is to be placed on a scale capable of weighing the appliance 

fully loaded with a resolution of ±1.0 lb (0.5 kg).

9.2 The appliance shall be fitted with the type of chimney recommended or 

provided by the manufacturer and extending to 15 ±0.5 feet (4.6 ± 0.15 m) from the 

upper surface of the scale. If no flue or chimney system is recommended or provided by 

the manufacturer, connect the appliance to a flue of a diameter equal to the flue outlet of 

the appliance. The flue section from the appliance flue collar to 8 ±0.5 feet above the 

scale shall be single wall stove pipe and the remainder of the flue shall be double wall 

insulated class A chimney.

9.3 Optional Equipment Use

9.3.1 A recirculation pump may be installed between connections at the top and 

bottom of the appliance to minimize thermal stratification if specified by the 

manufacturer. The pump shall not be installed in such a way as to change or affect the 

flow rate between the appliance and the heat exchanger.
Page 247 of 326

9.3.2 If the manufacturer specifies that a thermal control valve or other device be 

installed and set to control the return water temperature to a specific set point, the valve 

or other device shall be installed and set per the manufacturer’s written instructions.

9.4 Prior to filling the tank, weigh and record the appliance mass.

9.5 Heat Exchanger

9.5.1 Plumb the unit to a water-to-water heat exchanger with sufficient capacity to 

draw off heat at the maximum rate anticipated. Route hoses, electrical cables, and 

instrument wires in a manner that does not influence the weighing accuracy of the scale 

as indicated by placing dead weights on the platform and verifying the scale’s accuracy.

9.5.2 Locate thermocouples to measure the water temperature at the inlet and 

outlet of the load side of the heat exchanger.

9.5.3 Install a thermopile meeting the requirements of section 6.3 to measure the 

water temperature difference between the inlet and outlet of the load side of the heat 

exchanger.

9.5.4 Install a calibrated water flow meter in the heat exchanger load side supply 

line. The water flow meter is to be installed on the cooling water inlet side of the heat 

exchanger so that it will operate at the temperature at which it is calibrated.

9.5.5 Place the heat exchanger in a box with 2 in. (50 mm) of expanded 

polystyrene (EPS) foam insulation surrounding it to minimize heat losses from the heat 

exchanger. 

9.5.6 The reported efficiency and heat output rate shall be based on measurements 

made on the load side of the heat exchanger.
Page 248 of 326

9.5.7 Temperature instrumentation per section 6.6 shall be installed in the 

appliance outlet and return lines. The average of the outlet and return water temperature 

on the supply side of the system shall be considered the average appliance temperature 

for calculation of heat storage in the appliance (TFavg and TIavg). Installation of a water 

flow meter in the supply side of the system is optional. 

9.6 Fill the system with water. Determine the total weight of the water in the 

appliance when the water is circulating. Verify that the scale indicates a stable weight 

under operating conditions. Make sure air is purged properly.

10.0 Calibration and Standardization

10.1 Water Temperature Sensors. Temperature measuring equipment shall be 

calibrated before initial use and at least semi-annually thereafter. Calibrations shall be in 

compliance with National Institute of Standards and Technology (NIST) Monograph 175, 

Standard Limits of Error.

10.2 Heat Exchanger Load Side Water Flow Meter. 

10.2.1 The heat exchanger load side water flow meter shall be calibrated within 

the flow range used for the test run using NIST traceable methods. Verify the calibration 

of the water flow meter before and after each test run and at least once during each test 

run by comparing the water flow rate indicated by the flow meter to the mass of water 

collected from the outlet of the heat exchanger over a timed interval. Volume of the 

collected water shall be determined based on the water density calculated from section 

13, Eq. 8, using the water temperature measured at the flow meter. The uncertainty in the 

verification procedure used shall be 1 percent or less. The water flow rate determined by 
Page 249 of 326

the collection and weighing method shall be within 1 percent of the flow rate indicated by 

the water flow meter. 

10.3 Scales. The scales used to weigh the appliance and test fuel charge shall be 

calibrated using NIST traceable methods at least once every 6 months.

10.4 Moisture Meter. The moisture meter shall be calibrated per the 

manufacturer’s instructions and checked before each use.

10.5 Flue Gas Analyzers – In accordance with CSA B415.1-10, clause 6.8.

11.0 Conditioning

11.1 Prior to testing, the appliance is to be operated for a minimum of 50 hours 

using a medium heat draw rate. The conditioning may be at the manufacturer’s facility 

prior to the certification test. If the conditioning is at the certification test laboratory, the 

pre-burn for the first test can be included as part of the conditioning requirement. If 

conditioning is included in pre-burn, then the appliance shall be aged with fuel meeting 

the specifications outlined in sections 12.2 with a moisture content between 19 and 25 

percent on a dry basis. Operate the appliance at a medium burn rate (Category II or III) 

for at least 10 hours for noncatalytic appliances and 50 hours for catalytic appliances. 

Record and report hourly flue gas exit temperature data and the hours of operation. The 

aging procedure shall be conducted and documented by a testing laboratory.

12.0 Procedure

12.1 Appliance Installation. Assemble the appliance and parts in conformance 

with the manufacturer's written installation instructions. Clean the flue with an 

appropriately sized, wire chimney brush before each certification test series.
Page 250 of 326

12.2 Fuel. Test fuel charge fuel shall be red (Quercus ruba L.) or white (Quercus

alba) oak 19 to 25 percent moisture content on a dry basis. Piece length shall be 80 

percent of the firebox depth rounded down to the nearest 1 inch (25mm) increment. For 

example, if the firebox depth is 46 inches (1168mm) the 4 x 4 piece length would be 36 

inches (46 inches x 0.8 = 36.8 inches rounded down to 36 inches). Pieces are to be placed 

in the firebox parallel to the longest firebox dimension. For fireboxes with sloped 

surfaces that create a non-uniform firebox length, the piece length shall be adjusted for 

each layer based on 80 percent of the length at the level where the layer is placed. Pieces 

are to be spaced 3⁄4 inches (19 mm) apart on all faces. The first fuel layer may be 

assembled using fuel units consisting of multiple 4 x 4s consisting of single pieces with 

bottom and side spacers of 3 or more pieces if needed for a stable layer. The second layer 

may consist of fuel units consisting of no more than two pieces with spacers attached on 

the bottom and side. The top two layers of the fuel charge must consist of single pieces 

unless the fuel charge is only three layers. In that instance only the top layer must consist 

of single units. Three-quarter inch (19 mm) by 1.5 inch (38 mm) spacers shall be attached 

to the bottom of piece to maintain a 3⁄4 inch (19 mm) separation. When a layer consists of 

two or more units of 4 x 4s an additional 3⁄4 inch (19 mm) thick by 1.5 inch (38 mm) wide 

spacer shall be attached to the vertical face of each end of one 4 x 4, such that the 3⁄4 inch 

(19 mm) space will be maintained when two 4 x 4 units or pieces are loaded side by side. 

In cases where a layer contains an odd number of 4 x 4s one piece shall not be attached, 

but shall have spacers attached in a manner that will provide for the 3⁄4 inch (19 mm) 

space to be maintained (See Figure 1). Spacers shall be attached perpendicular to the 

length of the 4 x 4s such that the edge of the spacer is 1 ± 0.25 inch from the end of the 4 
Page 251 of 326

x 4s in the previous layers. Spacers shall be red or white oak and will be attached with 

either nails (non-galvanized), brads or oak dowels. The use of kiln-dried wood is not 

allowed.

12.2.1 Using a fuel moisture meter as specified in section 6.7 of the test method, 

determine the fuel moisture for each test fuel piece used for the test fuel load by 

averaging at least five fuel moisture meter readings measured parallel to the wood grain. 

Penetration of the moisture meter insulated electrodes for all readings shall be 1/4 the 

thickness of the fuel piece or 19 mm (3/4 in.), whichever is lesser. One measurement 

from each of three sides shall be made at approximately 3 inches from each end and the 

center. Two additional measurements shall be made centered between the other three 

locations. Each individual moisture content reading shall be in the range of 18 to 28 

percent on a dry basis. The average moisture content of each piece of test fuel shall be in 

the range of 19 to 25 percent. It is not required to measure the moisture content of the 

spacers. Moisture shall not be added to previously dried fuel pieces except by storage 

under high humidity conditions and temperature up to 100oF. Fuel moisture shall be 

measured within 4 hours of using the fuel for a test.

12.2.2 Firebox Volume. Determine the firebox volume in cubic feet. Firebox 

volume shall include all areas accessible through the fuel loading door where firewood

could reasonably be placed up to the horizontal plane defined by the top of the loading 

door. A drawing of the firebox showing front, side and plan views or an isometric view 

with interior dimensions shall be provided by the manufacturer and verified by the 

laboratory. Calculations for firebox volume from computer aided design (CAD) software 

programs are acceptable and shall be included in the test report if used. If the firebox 
Page 252 of 326

volume is calculated by the laboratory the firebox drawings and calculations shall be 

included in the test report.

12.2.3 Test Fuel Charge. Test fuel charges shall be determined by multiplying the 

firebox volume by 10 pounds (4.54 kg) per ft3 (28L), or a higher load density as 

recommended by the manufacturer’s printed operating instructions, of wood (as used wet 

weight). Select the number of pieces of standard fuel that most nearly match this target 

weight. This is the standard fuel charge for all tests. For example, if the firebox loading 

area volume is 10 ft3(280L) and the firebox depth is 46 inches (1168 mm), test fuel 

charge target is 100 lbs (45 kg) minimum and the piece length is 36 inches (914 mm). If 

eight 4 x 4s, 36 inches long weigh 105 lbs (48 kg), use 8 pieces for each test fuel charge. 

All test fuel charges will be of the same configuration.

12.3 Sampling Equipment. Prepare the particulate emission sampling equipment 

as defined by ASTM E2515-11 Standard Test Method for Determination of Particulate 

Matter Emissions Collected In a Dilution Tunnel. Upon request, four-inch filters may be 

used. Upon request, Teflon membrane filters or Teflon-coated glass fiber filters may be 

used.

12.4 Appliance Startup. The appliance shall be fired with wood fuel of any 

species, size and moisture content at the laboratories’ discretion to bring it up to 

operating temperature. Operate the appliance until the water is heated to the upper 

operating control limit and has cycled at least two times. Then remove all unburned fuel, 

zero the scale and verify the scales accuracy using dead weights.

12.4.1 Pretest Burn Cycle. Reload appliance with oak wood and allow it to burn 

down to the specified coal bed weight. The pretest burn cycle fuel charge weight shall be 
Page 253 of 326

within ±10 percent of the test fuel charge weight. Piece size and length shall be selected 

such that charcoalization is achieved by the time the fuel charge has burned down to the 

required coal bed weight. Pieces with a maximum thickness of approximately 2 inches 

have been found to be suitable. Charcoalization is a general condition of the test fuel bed 

evidenced by an absence of large pieces of burning wood in the coal bed and the 

remaining fuel pieces being brittle enough to be broken into smaller charcoal pieces with 

a metal poker. Manipulations to the fuel bed prior to the start of the test run are to be 

done to achieve charcoalization while maintaining the desired heat output rate. During 

the pre-test burn cycle and at least one hour prior to starting the test run, adjust water 

flow to the heat exchanger to establish the target heat draw for the test. For the first test 

run the heat draw rate shall be equal to the manufacturer’s rated heat output capacity.

12.4.1.1 Allowable Adjustments. Fuel addition or subtractions, and coal bed 

raking shall be kept to a minimum but are allowed up to 15 minutes prior to the start of 

the test run. For the purposes of this method, coal bed raking is the use of a metal tool 

(poker) to stir coals, break burning fuel into smaller pieces, dislodge fuel pieces from 

positions of poor combustion, and check for the condition of charcoalization. Record all 

adjustments to and additions or subtractions of fuel, and any other changes to the 

appliance operations that occur during pretest ignition period. During the 15-minute 

period prior to the start of the test run, the wood heater loading door shall not be open 

more than a total of 1 minute. Coal bed raking is the only adjustment allowed during this 

period.

12.4.2 Coal Bed Weight. The appliance is to be loaded with the test fuel charge 

when the coal bed weight is between 10 percent and 20 percent of the test fuel charge 
Page 254 of 326

weight. Coals may be raked as necessary to level the coal bed but may only be raked and 

stirred once between 15 to 20 minutes prior to the addition of the test fuel charge.

12.5 Test Runs. For all test runs, the return water temperature to the hydronic 

heater must be equal to or greater than 120°F. Aquastat or other heater output control 

device settings that are adjustable shall be set using manufacturer specifications, either as 

factory set or in accordance with the owner’s manual, and shall remain the same for all 

burn categories.

Complete a test run in each heat output rate category, as follows:

12.5.1 Test Run Start. Once the appliance is operating normally and the pretest 

coal bed weight has reached the target value per section 12.4.2, tare the scale and load the 

full test charge into the appliance. Time for loading shall not exceed 5 minutes. The 

actual weight of the test fuel charge shall be measured and recorded within 30 minutes 

prior to loading. Start all sampling systems. 

12.5.1.1 Record all water temperatures, differential water temperatures and water 

flow rates at time intervals of one minute or less. 

12.5.1.2 Record particulate emissions data per the requirements of ASTM E2515.

12.5.1.3 Record data needed to determine overall efficiency (SLM) per the 

requirements of CSA B415.1-10, clauses 6.2.1, 6.2.2, 6.3, 8.5.7, 10.4.3 (a), 10.4.3(f), and 

13.7.9.3

12.5.1.3.1 Measure and record the test room air temperature in accordance with 

the requirements of CSA B415.1-10, clauses 6.2.1, 8.5.7 and 10.4.3 (g).

12.5.1.3.2 Measure and record the flue gas temperature in accordance with the 

requirements of CSA B415.1-10, clauses 6.2.2, 8.5.7 and 10.4.3 (f).
Page 255 of 326

12.5.1.3.3 Determine and record the carbon monoxide (CO) and carbon dioxide 

(CO2) concentrations in the flue gas in accordance with CSA B415.1-10, clauses 6.3, 

8.5.7 and 10.4.3 (i) and (j).

12.5.1.3.4 Measure and record the test fuel weight per the requirements of CSA 

B415.1-10, clauses 8.5.7 and 10.4.3 (h).

12.5.1.3.5 Record the test run time per the requirements of CSA B415.1-10,

clauses 10.4.3 (a).

12.5.1.4 Monitor the average heat output rate on the load side of the heat 

exchanger. If the heat output rate gets close to the upper or lower limit of the target range 

(±5 percent) adjust the water flow through the heat exchanger to compensate. Make 

changes as infrequently as possible while maintaining the target heat output rate. The first 

test run shall be conducted at the Category IV heat output rate to validate that the 

appliance is capable of producing the manufacturer’s rated heat output capacity.

12.5.2 Test Fuel Charge Adjustment. It is acceptable to adjust the test fuel charge 

(i.e., reposition) once during a test run if more than 60 percent of the initial test fuel 

charge weight has been consumed and more than 10 minutes have elapsed without a 

measurable (1 lb or 0. 5 kg ) weight change while the operating control is in the demand 

mode. The time used to make this adjustment shall be less than 60 seconds.

12.5.3 Test Run Completion. The test run is completed when the remaining 

weight of the test fuel charge is 0.0 lb (0.0 kg). End the test run when the scale has 

indicated a test fuel charge weight of 0.0 lb (0.0 kg) or less for 30 seconds.
Page 256 of 326

12.5.3.1 At the end of the test run, stop the particulate sampling train and overall 

efficiency (SLM) measurements, and record the run time, and all final measurement 

values.

12.5.4 Heat Output Capacity Validation. The first test run must produce a heat 

output rate that is within 10 percent of the manufacturer’s rated heat output capacity 

(Category IV) throughout the test run and an average heat output rate within 5 percent of 

the manufacturer’s rated heat output capacity. If the appliance is not capable of producing 

a heat output within these limits, the manufacturer’s rated heat output capacity is 

considered not validated and testing is to be terminated. In such cases, the tests may be 

restarted using a lower heat output capacity if requested by the manufacturer.

12.5.5 Additional Test Runs. Using the manufacturer’s rated heat output capacity 

as a basis, conduct a test for additional heat output categories as specified in section 4.3. 

It is not required to run these tests in any particular order.

12.5.6 Alternative Heat Output Rate for Category I. If an appliance cannot be 

operated in the Category I heat output range due to stopped combustion, two test runs 

shall be conducted at heat output rates within Category II, provided that the completed 

test run burn rate is no greater than the burn rate expected in home use. If this rate cannot 

be achieved, the test is not valid.

When the alternative heat output rate is used, the weightings for the weighted 

averages indicated in Table 2 shall be the average of the Category I and II weightings and 

shall be applied to both Category II results. The two completed runs in Category II will 

be deemed to meet the requirement for runs completed in both Category I and Category 

II. Appliances that are not capable of operation within Category II (<25 percent of 
Page 257 of 326

maximum) cannot be evaluated by this test method. The test report must include full 

documentation and discussion of the attempted runs, completed rums and calculations. 

12.5.6.1 Stopped Fuel Combustion. Evidence that an appliance cannot be operated 

at a Category I heat output rate due to stopped fuel combustion shall include 

documentation of two or more attempts to operate the appliance in burn rate Category I 

and fuel combustion has stopped prior to complete consumption of the test fuel charge. 

Stopped fuel combustion is evidenced when an elapsed time of 60 minutes or more has 

occurred without a measurable (1 lb or 0.5 kg) weight change in the test fuel charge while 

the appliance operating control is in the demand mode. Report the evidence and the 

reasoning used to determine that a test in burn rate Category I cannot be achieved. For 

example, two unsuccessful attempts to operate at an output rate of 10 percent of the rated 

output capacity are not sufficient evidence that burn rate Category I cannot be achieved. 

Note that section 12.5.6 requires that the completed test run burn rate can be no greater 

than the burn rate expected in home use. If this rate cannot be achieved, the test is not 

valid.

12.5.7 Appliance Overheating. Appliances shall be capable of operating in all heat 

output categories without overheating to be rated by this test method. Appliance 

overheating occurs when the rate of heat withdrawal from the appliance is lower than the 

rate of heat production when the unit control is in the idle mode. This condition results in 

the water in the appliance continuing to increase in temperature well above the upper 

limit setting of the operating control. Evidence of overheating includes: 1 hour or more of 

appliance water temperature increase above the upper temperature set-point of the 

operating control, exceeding the temperature limit of a safety control device (independent 
Page 258 of 326

from the operating control), boiling water in a non-pressurized system or activation of a 

pressure or temperature relief valve in a pressurized system.

12.6 Additional Test Runs. The testing laboratory may conduct more than one test 

run in each of the heat output categories specified in section 4.3.1. If more than one test 

run is conducted at a specified heat output rate, the results from at least two-thirds of the 

test runs in that heat output rate category shall be used in calculating the weighted 

average emission rate (See section 14.1.14). The measurement data and results of all test 

runs shall be reported regardless of which values are used in calculating the weighted 

average emission rate.

13.0 Calculation of Results

13.1 Nomenclature

ET – Total particulate emissions for the full test run as determined per ASTM E2515-11 in 

grams

Eg/MJ – Emissions rate in grams per megajoule of heat output

Elb/mmBtu output – Emissions rate in pounds per million Btu of heat output

Eg/kg – Emissions factor in grams per kilogram of dry fuel burned

Eg/hr – Emissions factor in grams per hour

HHV – Higher heating value of fuel = 8600 Btu/lb (19.990 MJ/kg)

LHV – Lower heating value of fuel = 7988 Btu/lb (18.567 MJ/kg)

ΔT – Temperature difference between water entering and exiting the heat exchanger

Qout − Total heat output in BTU’s (megajoules)

Qin − Total heat input available in test fuel charge in BTU (megajoules)

M − Mass flow rate of water in lb/min (kg/min)
Page 259 of 326

Vi – Volume of water indicated by a totalizing flow meter at the ith reading in gallons 

(liters)

Vf – Volumetric flow rate of water in heat exchange system in gallons per minute 

(liters/min)

Θ – Total length of test run in hours

ti − Data sampling interval in minutes

ηdel – Delivered heating efficiency in percent

Fi − Weighting factor for heat output category i (See Table 2)

T1 – Temperature of water at the inlet on the supply side of the heat exchanger

T2 – Temperature of the water at the outlet on the supply side of the heat exchanger

T3 – Temperature of water at the inlet to the load side of the heat exchanger

TIavg − Average temperature of the appliance and water at start of the test

TIavg – (T1 + T2)/2 at the start of the test, °F Eq.1

TFavg – Average temperature of the appliance and water at the end of the test

TFavg – (T1 + T2)/2 at the end of the test, °F Eq.2

MC – Fuel moisture content in percent dry basis

MCi – Average moisture content of individual 4 x 4 fuel pieces in percent dry basis

MCsp – Moisture content of spacers assumed to be 10 percent dry basis

σ – Density of water in pounds per gallon

Cp – Specific heat of water in Btu /lb, °F

Csteel − Specific heat of steel (0.1 Btu/ lb, oF)

Wfuel – Fuel charge weight in pounds (kg)

Wi – Weight of individual fuel 4 x 4 pieces in pounds (kg)
Page 260 of 326

Wsp – Weight of all spacers used in a fuel load in pounds (kg)

Wapp − Weight of empty appliance in pounds

Wwa – Weight of water in supply side of the system in pounds

13.2 After the test is completed, determine the particulate emissions ET in 

accordance with ASTM E2515-11.

13.3 Determine Average Fuel Load Moisture Content

MCAve = [[ Σ Wi x MCi] + [ Wsp x MCsp ]] ÷ Wfuel, % Eq. 3

13.4 Determine heat input

Qin = (Wfuel/(1+(MC/100))) x HHV, BTU Eq. 4

Qin LHV = (Wfuel/(1+(MC/100))) x LHV, BTU Eq. 5

13.5 Determine Heat Output and Efficiency

13.5.1 Determine heat output as:

Qout = Σ [Heat output determined for each sampling time interval]+ Change in heat stored 

in the appliance.

 ( ) ( ) ( ) out p i i i i Wapp CSteel Cp aWwater TFavg TIavg Q   C  T  M  t     

, BTU Eq. 6

Note: The subscript (i) indicates the parameter value for sampling time interval ti.

Mi = Mass flow rate = gal/min x density of water (lb/gal) = lb/min

Mi =Vfi · σi, lb/min Eq. 7

Σi = (62.56 + ( -.0003413 x T3i) + ( -.00006225 x T3i

2

)) 0.1337, lbs/gal Eq. 8

Cp = 1.0014 + ( -.000003485 x T3i) Btu/lb, oF Eq. 9

Csteel = 0.1 Btu/lb, oF

Cpa = 1.0014 + (-.000003485 X (TIavg +TFavg)/2), Btu/lb-oF Eq. 10

Vfi = (Vi –Vi-1)/(ti-ti-1), gal/min Eq. 11
Page 261 of 326

Note: Vi is the total water volume at the end of interval i and Vi-1 is the total water volume 

at the beginning of the time interval. This calculation is necessary when a totalizing type 

water meter is used.

13.5.2 Determine heat output rate as:

Heat Output Rate = Qout/Θ, BTU/hr Eq. 12

13.5.3 Determine emission rates and emission factors as:

Eg/MJ = ET/(Qout x 0.001055), g/MJ Eq. 13

Elb/MM BTU output = (ET/453.59)/(Qoutput x 10-6), lb/mmBtu Out Eq. 14

Eg/kg = ET/(Wfuel/(1+MC/100)), g/dry kg Eq, 15

Eg/hr = ET/Θ, g/hr Eq. 16

13.5.4 Determine delivered efficiency as:

ηdel = (Qout/Qin) x 100, % Eq. 17

ηdel LHV = (Qout/Qin LHV) x 100, % Eq. 18

13.5.5 Determine ηSLM - Overall Efficiency (SLM) using Stack Loss 

For determination of the average overall thermal efficiency (ηSLM) for the test run, 

use the data collected over the full test run and the calculations in accordance with CSA 

B415.1-10, clause 13.7 except for 13.7.2 (e), (f), (g), and (h), use the following average 

fuel properties for oak: percent C = 50.0, percent H = 6.6, percent O = 43.2, percent ash = 

0.2 percent. The averaging period for determination of efficiency by the stack loss 

method allows averaging over 10 minute time periods for flue gas temperature, flue gas 

CO2, and flue gas CO for the determination of the efficiency. However, under some 

cycling conditions the “on” period may be short relative to this 10 minute period. For this 

reason, during cycling operation the averaging period for these parameters may not be 
Page 262 of 326

longer than the burner on period divided by 10. The averaging period need not be shorter 

than one minute. During the off period, under cycling operation, the averaging periods 

specified may be used. Where short averaging times are used, however, the averaging 

period for fuel consumption may still be at 10 minutes. This average wood consumption 

rate shall be applied to all of the smaller time intervals included. 

13.5.5.1 Whenever the CSA B415.1-10 overall efficiency is found to be lower 

than the overall efficiency based on load side measurements, as determined by Eq. 16 of 

this method, section 14.1.7 of the test report must include a discussion of the reasons for 

this result.

13.6 Weighted Average Emissions and Efficiency

13.6.1 Determine the weighted average emission rate and delivered efficiency from 

the individual tests in the specified heat output categories. The weighting factors (Fi) are 

derived from an analysis of ASHRAE bin data which provides details of normal building 

heating requirements in terms of percent of design capacity and time in a particular 

capacity range – or “bin” - over the course of a heating season. The values used in this 

method represent an average of data from several cities located in the northern United 

States.

Weighted average delivered efficiency: ηavg = Σ ηi x Fi, % Eq. 19

Weighted average emissions: Eavg = ΣEi x Fi, % Eq. 20

13.7 Average Heat Output (Qout-8hr) and Efficiency ((ηavg-8hr) for 8 hour burn time.

13.7.1 Units tested under this standard typically require infrequent fuelling, 8 to 12 

hours intervals being typical. Rating unit’s based on an average output sustainable over an 
Page 263 of 326

8 hour duration will assist consumers in appropriately sizing units to match the theoretical 

heat demand of their application.

13.7.2 Calculations:

Qout-8hr = X1 + { ( 8 - Y1 ) x [ ( X2 - X1 ) / ( Y2 - Y1 ) ] }, % Eq. 21

ηavg-8hr = ηdel1 + { ( 8 - Y1 ) x [ (ηdel2 - ηdel1 ) / ( Y2 - Y1 ) ] }, % Eq. 22

Where:

Y1 = Test duration just above 8 hrs

Y2 = Test duration just below 8 hrs

X1 = Actual load for duration Y1

X2 = Actual load for duration Y2

ηdel1 = Average delivered efficiency for duration Y1

ηdel2 = Average delivered efficiency for duration Y2

13.7.2.1 Determine the test durations and actual load for each category as recorded 

in Table 1A.

13.7.2.2 Determine the data point that has the nearest duration greater than 8 hrs. 

X1 = Actual load, 

Y1 = Test duration, and

ηdel1 = Average delivered efficiency for this data point

13.7.2.3 Determine the data point that has the nearest duration less than 8 hours.

X2 = Actual load, 

Y2 = Test duration, and 

ηdel2 = Average delivered efficiency for this data point

13.7.2.4 Example:
Page 264 of 326

Category Actual Load Duration

Category Actual Load Duration ηdel

(Btu/Hr) (Hr)

(%)

1 15,000 10.2 

70.0

2 26,000 8.4

75.5

3 50,000 6.4

80.1

4 100,000 4.7

80.9

Category 2 duration is just above 8 hours, therefore: X1 = 26,000 Btu/hr, ηdel1 = 75.5% and 

Y1 = 8.4 hrs

Category 3 duration is just below 8 hours, therefore: X2 = 50,000 Btu/hr, ηdel2 = 80.1% and 

Y2 = 6.4 hrs

Qout-8hr = 26,000 + {(8 - 8.4) x [(50,000 - 26,000) / (6.4 - 8.4)]}

= 30,800 BTU/hr

ηavg-8hr = 75.5 + {(8 - 8.4) x [(80.1 – 75.5) / (6.4 - 8.4)]} = 76.4%

13.8 Carbon Monoxide Emissions 

For each minute of the test period, the carbon monoxide emission rate shall be 

calculated as: 

COg/min = Qstd ∙ COs ∙ 3.30x10-5 Eq. 23

Total CO emissions for each of the three test periods (CO_1, CO_2, CO_3) shall be 

calculated as the sum of the emission rates for each of the 1 minute intervals. 
Page 265 of 326

Total CO emission for the test run, COT, shall be calculated as the sum of CO_1, CO_2, 

and CO_3. 

14.0 Report

14.1.1 The report shall include the following.

14.1.2 Name and location of the laboratory conducting the test.

14.1.3 A description of the appliance tested and its condition, date of receipt and 

dates of tests.

14.1.4 A statement that the test results apply only to the specific appliance tested.

14.1.5 A statement that the test report shall not be reproduced except in full, 

without the written approval of the laboratory.

14.1.6 A description of the test procedures and test equipment including a 

schematic or other drawing showing the location of all required test equipment. Also, a 

description of test fuel sourcing, handling and storage practices shall be included.

14.1.7 Details of deviations from, additions to or exclusions from the test method, 

and their data quality implications on the test results (if any), as well as information on 

specific test conditions, such as environmental conditions.

14.1.8 A list of participants and observers present for the tests.

14.1.9 Data and drawings indicating the fire box size and location of the fuel 

charge.

14.1.10 Drawings and calculations used to determine firebox volume.

14.1.11 Information for each test run fuel charge including piece size, moisture 

content, and weight.
Page 266 of 326

14.1.12 All required data for each test run shall be provided in spreadsheet format. 

Formulae used for all calculations shall be accessible for review.

14.1.13 Test run duration for each test.

14.1.14 Calculated results for delivered efficiency at each burn rate and the 

weighted average emissions reported as total emissions in grams, pounds per mm Btu of 

delivered heat, grams per MJ of delivered heat, grams per kilogram of dry fuel and grams 

per hour. Results shall be reported for each heat output category and the weighted 

average.

14.1.15 Tables 1A, 1B, 1C and Table 2 must be used for presentation of results in 

test reports.

14.1.16 A statement of the estimated uncertainty of measurement of the emissions 

and efficiency test results.

14.1.17 Raw data, calibration records, and other relevant documentation shall be 

retained by the laboratory for a minimum of 7 years.

15.0 Precision and Bias

15.1 Precision—It is not possible to specify the precision of the procedure in 

Method 28 WHH because the appliance operation and fueling protocols and the 

appliances themselves produce variable amounts of emissions and cannot be used to 

determine reproducibility or repeatability of this measurement method.

15.2 Bias—No definitive information can be presented on the bias of the 

procedure in Method 28 WHH for measuring solid fuel burning hydronic heater 

emissions because no material having an accepted reference value is available.

16.0 Keywords
Page 267 of 326

16.1 Solid fuel, hydronic heating appliances, wood-burning hydronic heaters.

Table 1A. Data Summary Part A

Table 1B. Data Summary Part B

Table 1C: Hangtag Information (optional)

MANUFACTURER:

MODEL NUMBER:

MAXIMUM OUTPUT RATING: Qmax BTU/HR

ANNUAL EFFICIENCY RATING: Ŋavg (Using higher heating value)

PARTICLE EMISSIONS: Eavg GRAMS/HR (average)

LBS/MILLION BTU OUTPUT

CARBON MONOXIDE: COg/MIN GRAMS/MINUTE
Page 268 of 326

Table 2. Annual Weighting 

Category Weighting 

Factor (Fi)

ηdel,i x Fi Eg/MJ,i x Fi Eg/kg,i x Fi Elb/mmBtu Out,i x Fi Eg/hr,i x Fi

I 0.437

II 0.238

III 0.275

IV 0.050

Totals 1.000
Page 269 of 326
Page 270 of 326

7. Part 60 Appendix A-8 is amended by adding Method 28 WHH-PTS to follow 

Method 28 WHH to read as follows:

A Test Method for Certification of Cord Wood-Fired Hydronic Heating Appliances 

with Partial Thermal Storage: Measurement of Particulate Matter (PM) and 

Carbon Monoxide (CO) Emissions and Heating Efficiency of Wood-Fired Hydronic 

Heating Appliances with Partial Thermal Storage

1.0 Scope and Application

1.1 This test method applies to wood-fired hydronic heating appliances with heat 

storage external to the appliance. The units typically transfer heat through circulation of a 

liquid heat exchange media such as water or a water-antifreeze mixture. Throughout this 

document, the term “water” will be used to denote any of the heat transfer liquids 

approved for use by the manufacturer. 

1.2 The test method measures PM and CO emissions and delivered heating 

efficiency at specified heat output rates referenced against the appliance’s rated heating 

capacity as specified by the manufacturer and verified under this test method. 

1.3 PM emissions are measured by the dilution tunnel method as specified in the 

EPA Method 28 WHH and the standards referenced therein with the exceptions noted in 

section 12.5.9. Delivered efficiency is measured by determining the fuel energy input and 

appliance output. Heat output is determined through measurement of the flow rate and 

temperature change of water circulated through a heat exchanger external to the appliance 

and the increase in energy of the external storage. Heat input is determined from the mass 

of dry wood fuel and its higher heating value (HHV). Delivered efficiency does not 

attempt to account for pipeline loss. 
Page 271 of 326

1.4 Products covered by this test method include both pressurized and nonpressurized hydronic heating appliances intended to be fired with wood and for which the 

manufacturer specifies for indoor or outdoor installation. The system, which includes the 

heating appliance and external storage, is commonly connected to a heat exchanger by 

insulated pipes and normally includes a pump to circulate heated liquid. These systems 

are used to heat structures such as homes, barns and greenhouses. They also provide heat 

for domestic hot water, spas and swimming pools. 

1.5 Distinguishing features of products covered by this standard include: 

1.5.1 The manufacturer specifies the application for either indoor or outdoor 

installation. 

1.5.2 A firebox with an access door for hand loading of fuel. 

1.5.3 Typically an aquastat mounted as part of the appliance that controls 

combustion air supply to maintain the liquid in the appliance within a predetermined 

temperature range provided sufficient fuel is available in the firebox. The appliance may 

be equipped with other devices to control combustion. 

1.5.4 A chimney or vent that exhausts combustion products from the appliance. 

1.5.5 A liquid storage system, typically water, which is not large enough to accept 

all of the heat produced when a full load of wood is burned and the storage system starts 

a burn cycle at 125°F. 

1.5.6 The heating appliances require external thermal storage and these units will 

only be installed as part of a system which includes thermal storage. The manufacturer 

specifies the minimum amount of thermal storage required. However, the storage system 
Page 272 of 326

shall be large enough to ensure that the boiler (heater) does not cycle, slumber, or go into 

an off-mode when operated in a Category III load condition (See section 4.3). 

1.6 The values stated are to be regarded as the standard whether in I-P or SI units. 

The values given in parentheses are for information only. 

2.0 Summary of Method and References 

2.1 PM and CO emissions are measured from a wood–fired hydronic heating 

appliance burning a prepared test fuel charge in a test facility maintained at a set of 

prescribed conditions. Procedures for determining heat output rates, PM and CO 

emissions, and efficiency and for reducing data are provided. 

2.2 Referenced Documents 

2.2.1 EPA Standards 

2.2.1.1 Method 28 Certification and Auditing of Wood Heaters 

2.2.1.2 Method 28 WHH Measurement of Particulate Emissions and Heating 

Efficiency of Wood-Fired Hydronic Heating Appliances and the Standards Referenced 

therein.

2.2.2 Other Standards 

2.2.2.1 CAN/CSA-B415.1-10 Performance Testing of Solid-Fuel-Burning 

Heating Appliances 

3.0 Terminology 

3.1 Definitions 

3.1.1 Hydronic Heating – A heating system in which a heat source supplies 

energy to a liquid heat exchange media such as water that is circulated to a heating load 

and returned to the heat source through pipes. 
Page 273 of 326

3.1.2 Aquastat – A control device that opens or closes a circuit to control the rate 

of fuel consumption in response to the temperature of the heating media in the heating 

appliance. 

3.1.3 Delivered Efficiency – The percentage of heat available in a test fuel charge 

that is delivered to a simulated heating load or the storage system as specified in this test 

method. 

3.1.4 Emission Factor – The emission of a pollutant expressed in mass per unit of 

energy (typically) output from the boiler/heater.

3.1.5 Emission Index – The emission of a pollutant expressed in mass per unit 

mass of fuel used.

3.1.6 Emission Rate – The emission of a pollutant expressed in mass per unit time 

3.1.7 Manufacturer’s Rated Heat Output Capacity −The value in Btu/hr (MJ/hr) 

that the manufacturer specifies that a particular model of hydronic heating appliance is 

capable of supplying at its design capacity as verified by testing, in accordance with 

section 12.5.4. 

3.1.8 Heat Output Rate − The average rate of energy output from the appliance 

during a specific test period in Btu/hr (MJ/hr).

3.1.9 Firebox − The chamber in the appliance in which the test fuel charge is 

placed and combusted. 

3.1.10 NIST – National Institute of Standards and Technology.

3.1.11 Test Fuel Charge − The collection of test fuel placed in the appliance at the 

start of the emission test run. 
Page 274 of 326

3.1.12 Test Run – An individual emission test which encompasses the time 

required to consume the mass of the test fuel charge. The time of the test run also 

considers the time for the energy to be drawn from the thermal storage. 

3.1.13 Test Run Under “Cold-to-Cold” Condition – Under this test condition the 

test fuel is added into an empty chamber along with kindling and ignition materials 

(paper). The boiler/heater at the start of this test is typically 125o to 130oF. 

3.1.14 Test Run Under “Hot-to-Hot” Condition – Under this test condition the test 

fuel is added onto a still-burning bed of charcoals produced in a pre-burn period. The 

boiler/heater water is near its operating control limit at the start of the test. 

3.1.15 Overall Efficiency, also known as Stack Loss Efficiency – The efficiency 

for each test run as determined using the CSA B415.1-10 stack loss method (SLM). 

3.1.16 Phases of a Burn Cycle – The “startup phase” is defined as the period from 

the start of the test until 15 percent of the test fuel charge is consumed. The “steady-state

phase” is defined as the period from the end of the startup phase to a point at which 80 

percent of the test fuel charge is consumed. The “end phase” is defined as the time from 

the end of the steady-state period to the end of the test. 

3.1.17 Thermopile – A device consisting of a number of thermocouples connected 

in series, used for measuring differential temperature. 

3.1.18 Slumber Mode – This is a mode in which the temperature of the water in 

the boiler/heater has exceeded the operating control limit and the control has changed the 

boiler/heater fan speed, dampers, and/or other operating parameters to minimize the heat 

output of the boiler/heater. 

4.0 Summary of Test Method 
Page 275 of 326

4.1 Dilution Tunnel. Emissions are determined using the “dilution tunnel” method 

specified in EPA Method 28 WHH and the standards referenced therein. The flow rate in 

the dilution tunnel is maintained at a constant level throughout the test cycle and 

accurately measured. Samples of the dilution tunnel flow stream are extracted at a 

constant flow rate and drawn through high efficiency filters. The filters are dried and 

weighed before and after the test to determine the emissions collected and this value is 

multiplied by the ratio of tunnel flow to filter flow to determine the total particulate 

emissions produced in the test cycle. 

4.2 Efficiency. The efficiency test procedure takes advantage of the fact that this 

type of system delivers heat through circulation of the heated liquid (water) from the 

system to a remote heat exchanger (e.g. baseboard radiators in a room) and back to the 

system. Measurements of the cooling water temperature difference as it enters and exits 

the test system heat exchanger along with the measured flow rate allow for an accurate 

determination of the useful heat output of the appliance. Also included in the heat output 

is the change in the energy content in the storage system during a test run. Energy input 

to the appliance during the test run is determined by weight of the test fuel charge, 

adjusted for moisture content, multiplied by the higher heating value. Additional 

measurements of the appliance weight and temperature at the beginning and end of a test 

cycle are used to correct for heat stored in the appliance. Overall efficiency (SLM) is 

determined using the CSA B415.1-10 stack loss method for data quality assurance 

purposes. 

4.3 Operation. Four test categories are defined for use in this method. These are: 
Page 276 of 326

4.3.1 Category I: A heat output of 15 percent or less of manufacturer’s rated heat 

output capacity. 

4.3.2 Category II: A heat output of 16 percent to 24 percent of manufacturer’s 

rated heat output capacity. 

4.3.3 Category III: A heat output of 25 percent to 50 percent of manufacturer’s 

rated heat output capacity. 

4.3.4 Category IV: Manufacturer’s Rated Heat Output Capacity. These heat 

output categories refer to the output from the system by way of the load heat exchanger 

installed for the test. The output from just the boiler/heater part of the system may be 

higher for all or part of a test, as part of this boiler/heater output goes to storage. 

For the Category III and IV runs, appliance operation is conducted on a hot-to-hot test 

cycle meaning that the appliance is brought to operating temperature and a coal bed is 

established prior to the addition of the test fuel charge and measurements are made for 

each test fuel charge cycle. The measurements are made under constant heat draw 

conditions within pre-determined ranges. No attempt is made to modulate the heat 

demand to simulate an indoor thermostat cycling on and off in response to changes in the 

indoor environment. 

For the Category I and II runs, the unit is tested with a “cold start.” At the 

manufacturer’s option, the Category II and III runs may be waived and it may be assumed 

that the particulate emission values and efficiency values determined in the startup, 

steady-state, and end phases of Category I are applicable in Categories II and III for the 

purpose of determining the annual averages in lb/mmBtu and g/MJ (See section 13). For 
Page 277 of 326

the annual average in g/hr, the length of time for stored heat to be drawn from thermal 

storage shall be determined for the test load requirements of the respective category. 

All test operations and measurements shall be conducted by personnel of the 

laboratory responsible for the submission of the test report. 

5.0 Significance and Use 

5.1 The measurement of particulate matter emission and CO rates is an important 

test method widely used in the practice of air pollution control. 

5.1.1 These measurements, when approved by state or federal agencies, are often 

required for the purpose of determining compliance with regulations and statutes. 

5.1.2 The measurements made before and after design modifications are necessary 

to demonstrate the effectiveness of design changes in reducing emissions and make this 

standard an important tool in manufacturers’ research and development programs. 

5.2 Measurement of heating efficiency provides a uniform basis for comparison of 

product performance that is useful to the consumer. It is also required to relate emissions 

produced to the useful heat production. 

5.3 This is a laboratory method and is not intended to be fully representative of all 

actual field use. It is recognized that users of hand-fired, wood-burning equipment have a 

great deal of influence over the performance of any wood-burning appliance. Some 

compromises in realism have been made in the interest of providing a reliable and 

repeatable test method. 

6.0 Test Equipment
Page 278 of 326

6.1 Scale. A platform scale capable of weighing the boiler/heater under test and 

associated parts and accessories when completely filled with water to an accuracy of ± 

1.0 pound (± 0.5 kg) and a readout resolution of ± 0.2 pound (± 0.1 kg). 

6.2 Heat Exchanger. A water-to-water heat exchanger capable of dissipating the 

expected heat output from the system under test. 

6.3 Water Temperature Difference Measurement. A Type – T ‘special limits’ 

thermopile with a minimum of 5 pairs of junctions shall be used to measure the 

temperature difference in water entering and leaving the heat exchanger. The temperature 

difference measurement uncertainty of this type of thermopile is equal to or less than ± 

0.50oF (± 0.25oC). Other temperature measurement methods may be used if the 

temperature difference measurement uncertainty is equal to or less than ± 0.50oF (± 

0.25oC). This measurement uncertainty shall include the temperature sensor, sensor well 

arrangement, piping arrangements, lead wire, and measurement / recording system. The 

response time of the temperature measurement system shall be less than half of the time 

interval at which temperature measurements are recorded. 

6.4 Water Flow Meter. A water flow meter shall be installed in the inlet to the 

load side of the heat exchanger. The flow meter shall have an accuracy of ± 1 percent of 

measured flow. 

6.4.1 Optional – Appliance Side Water Flow Meter. A water flow meter with an 

accuracy of ± 1 percent of the flow rate is recommended to monitor supply side water 

flow rate. 

6.5 Optional Recirculation Pump. Circulating pump used during test to prevent 

stratification, in the boiler/heater, of liquid being heated. 
Page 279 of 326

6.6 Water Temperature Measurement. Thermocouples or other temperature 

sensors to measure the water temperature at the inlet and outlet of the load side of the 

heat exchanger must meet the calibration requirements specified in 10.1 of this method. 

6.7 Lab Scale. For measuring the moisture content of wood slices as part of the 

overall wood moisture determination. Accuracy of ±0.01 pounds.

6.8 Flue Gas Temperature Measurement. Must meet the requirements of CSA 

B415.1-10, clause 6.2.2. 

6.9 Test Room Temperature Measurement. Must meet the requirements of CSA 

B415.1-10, clause 6.2.1. 

6.10 Flue Gas Composition Measurement. Must meet the requirements of CSA 

B415.1-10, clauses 6.3.1 through 6.3.3. 

6.11 Dilution Tunnel CO Measurement. In parallel with the flue gas composition 

measurements, the CO concentration in the dilution tunnel shall also be measured and 

reported at time intervals not to exceed one minute. This analyzer shall meet the zero and 

span drift requirements of CSA B415.1-10. In addition the measurement repeatability 

shall be better than ±15 ppm over the range of CO levels observed in the dilution tunnel. 

7.0 Safety 

7.1 These tests involve combustion of wood fuel and substantial release of heat 

and products of combustion. The heating system also produces large quantities of very 

hot water and the potential for steam production and system pressurization. Appropriate 

precautions must be taken to protect personnel from burn hazards and respiration of 

products of combustion. 

8.0 Sampling, Test Specimens and Test Appliances 
Page 280 of 326

8.1 Test specimens shall be supplied as complete appliances, as described in 

marketing materials, including all controls and accessories necessary for installation in 

the test facility. A full set of specifications, installation and operating instructions, and 

design and assembly drawings shall be provided when the product is to be placed under 

certification of a third-party agency. The manufacturer’s written installation and 

operating instructions are to be used as a guide in the set-up and testing of the appliance 

and shall be part of the test record. 

8.2 The size, connection arrangement, and control arrangement for the thermal 

storage shall be as specified in the manufacturer’s documentation. It is not necessary to 

use the specific storage system that the boiler/heater will be marketed with. However, the 

capacity of the system used in the test cannot be greater than that specified as the 

minimum allowable for the boiler/heater. 

8.3 All system control settings shall be the as-shipped, default settings. These 

default settings shall be the same as those communicated in a document to the installer or 

end user. These control settings and the documentation of the control settings as to be 

provided to the installer or end user shall be part of the test record. 

8.4 Where the manufacturer defines several alternatives for the connection and 

loading arrangement, one shall be defined in the appliance documentation as the default 

or standard installation. It is expected that this will be the configuration for use with a 

simple baseboard heating system. This is the configuration to be followed for these tests. 

The manufacturer’s documentation shall define the other arrangements as optional or 

alternative arrangements. 

9.0 Preparation of Test Equipment 
Page 281 of 326

9.1 The appliance is to be placed on a scale capable of weighing the appliance 

fully loaded with a resolution of ±0.2 lb (0.1 kg). 

9.2 The appliance shall be fitted with the type of chimney recommended or 

provided by the manufacturer and extending to 15 ±0.5 feet (4.6 ±0.15 m) from the upper 

surface of the scale. If no flue or chimney system is recommended or provided by the 

manufacturer, connect the appliance to a flue of a diameter equal to the flue outlet of the 

appliance. The flue section from the appliance flue collar to 8 ±0.5 feet above the scale 

shall be single wall stove pipe and the remainder of the flue shall be double wall insulated 

class A chimney. 

9.3 Optional Equipment Use 

9.3.1 A recirculation pump may be installed between connections at the top and 

bottom of the appliance to minimize thermal stratification if specified by the 

manufacturer. The pump shall not be installed in such a way as to change or affect the 

flow rate between the appliance and the heat exchanger. 

9.3.2 If the manufacturer specifies that a thermal control valve or other device be 

installed and set to control the return water temperature to a specific set point, the valve 

or other device shall be installed and set per the manufacturer’s written instructions. 

9.4 Prior to filling the boiler/heater with water, weigh and record the appliance 

mass. 

9.5 Heat Exchanger 

9.5.1 Plumb the unit to a water-to-water heat exchanger with sufficient capacity to 

draw off heat at the maximum rate anticipated. Route hoses and electrical cables and 
Page 282 of 326

instrument wires in a manner that does not influence the weighing accuracy of the scale

as indicated by placing dead weights on the platform and verifying the scale’s accuracy. 

9.5.2 Locate thermocouples to measure the water temperature at the inlet and 

outlet of the load side of the heat exchanger. 

9.5.3 Install a thermopile (or equivalent instrumentation) meeting the 

requirements of section 6.3 to measure the water temperature difference between the inlet 

and outlet of the load side of the heat exchanger

9.5.4 Install a calibrated water flow meter in the heat exchanger load side supply 

line. The water flow meter is to be installed on the cooling water inlet side of the heat 

exchanger so that it will operate at the temperature at which it is calibrated. 

9.5.5 Place the heat exchanger in a box with 2 in. (50 mm) of expanded 

polystyrene (EPS) foam insulation surrounding it to minimize heat losses from the heat 

exchanger. 

9.5.6 The reported efficiency and heat output rate shall be based on measurements 

made on the load side of the heat exchanger. 

9.5.7 Temperature instrumentation per section 6.6 shall be installed in the 

appliance outlet and return lines. The average of the outlet and return water temperature 

on the supply side of the system shall be considered the average appliance temperature 

for calculation of heat storage in the appliance (TFavg and TIavg). Installation of a water 

flow meter in the supply side of the system is optional. 

9.6 Storage Tank. The storage tank shall include a destratification pump as 

illustrated in Figure 1. The pump will draw from the bottom of the tank and return to the 

top as illustrated. Temperature sensors (TS1 and TS2 in Figure 1) shall be included to 
Page 283 of 326

measure the temperature in the recirculation loop. The valve plan in Figure 1 allows the 

tank recirculation loop to operate and the boiler/heater-to-heat exchanger loop to operate 

at the same time but in isolation. This would typically be done before the start of a test or 

following completion of a test to determine the end of test average tank temperature. The 

nominal flow rate in the storage tank recirculation loop can be estimated based on pump 

manufacturers’ performance curves and any significant restriction in the recirculation 

loop. 

9.7 Fill the system with water. Determine the total weight of the water in the 

appliance when the water is circulating. Verify that the scale indicates a stable weight 

under operating conditions. Make sure air is purged properly. 

10.0 Calibration and Standardization 

10.1 Water Temperature Sensors. Temperature measuring equipment shall be 

calibrated before initial use and at least semi-annually thereafter. Calibrations shall be in 

compliance with National Institute of Standards and Technology (NIST) Monograph 175, 

Standard Limits of Error. 

10.2 Heat Exchanger Load Side Water Flow Meter. 

10.2.1 The heat exchanger load side water flow meter shall be calibrated within 

the flow range used for the test run using NIST-traceable methods. Verify the calibration 

of the water flow meter before and after each test run and at least once during each test 

run by comparing the water flow rate indicated by the flow meter to the mass of water 

collected from the outlet of the heat exchanger over a timed interval. Volume of the 

collected water shall be determined based on the water density calculated from section 

13, Eq. 12, using the water temperature measured at the flow meter. The uncertainty in 
Page 284 of 326

the verification procedure used shall be 1 percent or less. The water flow rate determined 

by the collection and weighing method shall be within 1 percent of the flow rate indicated 

by the water flow meter. 

10.3 Scales. The scales used to weigh the appliance and test fuel charge shall be 

calibrated using NIST-traceable methods at least once every 6 months. 

10.4 Flue Gas Analyzers – In accordance with CSA B415.1-10, clause 6.8. 

11.0 Conditioning 

11.1 Prior to testing, an appliance is to be operated for a minimum of 50 hours 

using a medium heat draw rate. The conditioning may be at the manufacturer’s facility 

prior to the certification test. If the conditioning is at the certification test laboratory, the 

pre-burn for the first test can be included as part of the conditioning requirement. If 

conditioning is included in pre-burn, then the appliance shall be aged with fuel meeting 

the specifications outlined in section 12.2 with a moisture content between 19 and 25 

percent on a dry basis. Operate the appliance at a medium heat output rate (Category II or 

III) for at least 10 hours for non-catalytic appliances and 50 hours for catalytic 

appliances. Record and report hourly flue gas exit temperature data and the hours of 

operation. The aging procedure shall be conducted and documented by a testing 

laboratory. 

12.0 Procedure 

12.1 Appliance Installation. Assemble the appliance and parts in conformance 

with the manufacturer's written installation instructions. Clean the flue with an 

appropriately sized, wire chimney brush before each certification test series. 
Page 285 of 326

12.2 Fuel. Test fuel charge fuel shall be red (Quercus ruba L.) or white (Quercus 

Alba) oak 19 to 25 percent moisture content on a dry basis. Piece length shall be 80 

percent of the firebox depth rounded down to the nearest 1 inch (25mm) increment. For 

example, if the firebox depth is 46 inches (1168mm) the piece length would be 36 inches 

(46 inches x 0.8 = 36.8 inches, rounded down to 36 inches). Pieces are to be placed in the 

firebox parallel to the longest firebox dimension. For fireboxes with sloped surfaces that 

create a non-uniform firebox length, the piece length shall be adjusted for each layer 

based on 80 percent of the length at the level where the layer is placed. The test fuel shall 

be cord wood with cross section dimensions and weight limits as defined in CSA B415.1-

10, section 8.3, Table 4. The use of dimensional lumber is not allowed. 

12.2.1 Select three pieces of cord wood from the same batch of wood as the test 

fuel and the same weight as the average weight of the pieces in the test load ± 1.0 lb. 

From each of these three pieces, cut three slices. Each slice shall be 1⁄2 inch to 3⁄4 inch 

thick. One slice shall be cut across the center of the length of the piece. The other two 

slices shall be cut half way between the center and the end. Immediately measure the 

mass of each piece in pounds. Dry each slice in an oven at 220°F for 24 hours or until no 

further weight change occurs. The slices shall be arranged in the oven so as to provide 

separation between faces. Remove from the oven and measure the mass of each piece 

again as soon as practical, in pounds. 

The moisture content of each slice, on a dry basis, shall be calculated as: 

MCslice = 100 ∙ (WSliceWet – WSliceDry)

 WSliceDry

Where: 
Page 286 of 326

WSliceWet = weight of the slice before drying in pounds 

WSliceDry = weight of the slice after drying in pounds 

MCSlice = moisture content of the slice in % dry basis 

The average moisture content of the entire test load (MC) shall be determined 

using Eq. 6. Each individual slice shall have a moisture content in the range of 18 percent 

to 28 percent on a dry basis. The average moisture content for the test fuel load shall be 

in the range of 19 percent to 25 percent. Moisture shall not be added to previously dried 

fuel pieces except by storage under high humidity conditions and temperature up to 

100oF. Fuel moisture measurement shall begin within 4 hours of using the fuel batch for a 

test. Use of a pin-type meter to estimate the moisture content prior to a test is 

recommended. 

12.2.2 Firebox Volume. Determine the firebox volume in cubic feet. Firebox 

volume shall include all areas accessible through the fuel loading door where firewood 

could reasonably be placed up to the horizontal plane defined by the top of the loading 

door. A drawing of the firebox showing front, side and plan views or an isometric view 

with interior dimensions shall be provided by the manufacturer and verified by the 

laboratory. Calculations for firebox volume from computer aided design (CAD) software 

programs are acceptable and shall be included in the test report if used. If the firebox 

volume is calculated by the laboratory the firebox drawings and calculations shall be 

included in the test report. 

12.2.3 Test Fuel charge. Test fuel charges shall be determined by multiplying the 

firebox volume by 10 pounds (4.54 kg) per ft3(28L), or a higher load density as 

recommended by the manufacturer’s printed operating instructions, of wood (as used wet 
Page 287 of 326

weight). Select the number of pieces of cord wood that most nearly match this target 

weight. However, the test fuel charge cannot be less than the target of 10 pounds (4.54 

kg) per ft3(28L). 

12.3 Sampling Equipment. Prepare the particulate emission sampling equipment 

as defined by EPA Method 28 WHH and the standards referenced therein. 

12.4 Appliance Startup. The appliance shall be fired with wood fuel of any 

species, size and moisture content, at the laboratory’s discretion, to bring it up to 

operating temperature. Operate the appliance until the water is heated to the upper 

operating control limit and has cycled at least two times. Then remove all unburned fuel, 

zero the scale and verify the scales accuracy using dead weights.

12.4.1 Startup Procedure for Category III and IV Test Runs, “Hot-to-Hot.” 

12.4.1.1 Pretest t Burn Cycle. Following appliance startup (section 12.4), reload 

appliance with oak cord wood and allow it to burn down to the specified coal bed weight. 

The pre-test burn cycle fuel charge weight shall be within ±10 percent of the test fuel 

charge weight. Piece size and length shall be selected such that charcoalization is 

achieved by the time the fuel charge has burned down to the required coal bed weight. 

Pieces with a maximum thickness of approximately 2 inches have been found to be 

suitable. Charcoalization is a general condition of the test fuel bed evidenced by an 

absence of large pieces of burning wood in the coal bed and the remaining fuel pieces 

being brittle enough to be broken into smaller charcoal pieces with a metal poker. 

Manipulations to the fuel bed prior to the start of the test run are to be done to achieve 

charcoalization while maintaining the desired heat output rate. During the pre-test burn 

cycle and at least one hour prior to starting the test run, adjust water flow to the heat 
Page 288 of 326

exchanger to establish the target heat draw for the test. For the first test run the heat draw 

rate shall be equal to the manufacturer’s rated heat output capacity. 

12.4.1.2 Allowable Adjustments. Fuel addition or subtractions, and coal bed 

raking shall be kept to a minimum but are allowed up to 15 minutes prior to the start of 

the test run. For the purposes of this method, coal bed raking is the use of a metal tool 

(poker) to stir coals, break burning fuel into smaller pieces, dislodge fuel pieces from 

positions of poor combustion, and check for the condition of charcoalization. Record all 

adjustments to and additions or subtractions of fuel, and any other changes to the 

appliance operations that occur during pretest ignition period. During the 15-minute 

period prior to the start of the test run, the wood heater loading door shall not be open 

more than a total of 1 minute. Coal bed raking is the only adjustment allowed during this 

period. 

12.4.1.3 Coal Bed Weight. The appliance is to be loaded with the test fuel charge 

when the coal bed weight is between 10 percent and 20 percent of the test fuel charge 

weight. Coals may be raked as necessary to level the coal bed but may only be raked and 

stirred once between 15 to 20 minutes prior to the addition of the test fuel charge. 

12.4.1.4 Storage. The Category III and IV test runs may be done either with or 

without the thermal storage. If thermal storage is used, the initial temperature of the 

storage must be 125°F or greater at the start of the test. The storage may be heated during 

the pre-test burn cycle or it may be heated by external means. If thermal storage is used, 

prior to the start of the test run, the storage tank destratification pump, shown in Figure 1, 

shall be operated until the total volume pumped exceeds 1.5 times the tank volume and 

the difference between the temperature at the top and bottom of the storage tank (TS1 and 
Page 289 of 326

TS2) is less than 1°F. These two temperatures shall then be recorded to determine the 

starting average tank temperature. The total volume pumped may be based on the 

nominal flow rate of the destratification pump (See section 9.6). If the Category III and 

IV runs are done with storage, it is recognized that during the last hour of the pre-burn 

cycle the storage tank must be mixed to achieve a uniform starting temperature and 

cannot receive heat from the boiler/heater during this time. During this time period, the 

boiler/heater might cycle or go into a steady reduced output mode. (Note – this would 

happen, for example, in a Category IV run if the actual maximum output of the 

boiler/heater exceed the manufacturer’s rated output.) A second storage tank may be used 

temporarily to enable the boiler/heater to operate during this last hour of the pre-burn 

period as it will during the test period. The temperature of this second storage tank is not 

used in the calculations but the return water to the boiler/heater (after mixing device if 

used) must be 125°F or greater. 

12.4.2 Startup Procedure for Category I and II Test Runs, “Cold-to-Cold.” 

12.4.2.1 Initial Temperatures. This test shall be started with both the boiler/heater 

and the storage at a minimum temperature of 125°F. The boiler/heater maximum 

temperature at the start of this test shall be 135°F. The boiler/heater and storage may be 

heated through a pre-burn or it may be heated by external means. 

12.4.2.2 Firebox Condition at Test Start. Prior to the start of this test remove all 

ash and charcoal from the combustion chamber(s). The loading of the test fuel and 

kindling should follow the manufacturer’s recommendations, subject to the following 

constraints: Up to 10 percent kindling and paper may be used which is in addition to the 
Page 290 of 326

fuel load. Further, up to 10 percent of the fuel load (i.e., included in the 10 lb/ft3) may be 

smaller than the main fuel. This startup fuel shall still be larger than 2 inches. 

12.4.2.3 Storage. The Category I and II test runs shall be done with thermal 

storage. The initial temperature of the storage must be 125°F or greater at the start of the 

test. The storage may be heated during the pre-test burn cycle or it may be heated by 

external means. Prior to the start of the test run, the storage tank destratification pump, 

shown in Figure 1, shall be operated until the total volume pumped exceeds 1.5 times the 

tank volume and the difference between the temperature at the top and bottom of the 

storage tank (TS1 and TS2) is less than 1°F. These two temperatures shall then be 

recorded to determine the starting average tank temperature. The total volume pumped 

may be based on the nominal flow rate of the destratification pump (See section 9.6). 

12.5 Test Runs. For all test runs, the return water temperature to the hydronic 

heater must be equal to or greater than 120°F (this is lower than the initial tank 

temperature to allow for any pipeline losses). Where the storage system is used, flow of 

water from the boiler/heater shall be divided between the storage tank and the heat 

exchanger such that the temperature change of the circulating water across the heat 

exchanger shall be 30 ±5°F, averaged over the entire test run. This is typically adjusted 

using the system valves. 

Complete a test run in each heat output rate category, as follows: 

12.5.1 Test Run Start. For Category III and IV runs: once the appliance is 

operating normally and the pretest coal bed weight has reached the target value per 

section 12.4.1, tare the scale and load the full test charge into the appliance. Time for 
Page 291 of 326

loading shall not exceed 5 minutes. The actual weight of the test fuel charge shall be 

measured and recorded within 30 minutes prior to loading. Start all sampling systems. 

For Category I and II runs: once the appliance has reached the starting 

temperature, tare the scale and load the full test charge, including kindling into the 

appliance. The actual weight of the test fuel charge shall be measured and recorded 

within 30 minutes prior to loading. Light the fire following the manufacturer’s written 

normal startup procedure. Start all sampling systems. 

12.5.1.1 Record all water temperatures, differential water temperatures and water 

flow rates at time intervals of one minute or less. 

12.5.1.2 Record particulate emissions data per the requirements of EPA Method 

28 WHH and the standards referenced therein. 

12.5.1.3 Record data needed to determine overall efficiency (SLM) per the 

requirements of CSA B415.1-10 clauses 6.2.1, 6.2.2, 6.3, 8.5.7, 10.4.3(a), 10.4.3(f), and 

13.7.9.3 

12.5.1.3.1 Measure and record the test room air temperature in accordance with 

the requirements of CSA B415.1-10, clauses 6.2.1, 8.5.7 and 10.4.3(g). 

12.5.1.3.2 Measure and record the flue gas temperature in accordance with the 

requirements of CSA B415.1-10, clauses 6.2.2, 8.5.7 and 10.4.3(f). 

12.5.1.3.3 Determine and record the carbon monoxide (CO) and carbon dioxide 

(CO2) concentrations in the flue gas in accordance with CSA B415.1-10, clauses 6.3, 

8.5.7 and 10.4.3(i) and (j). 

12.5.1.3.4 Measure and record the test fuel weight per the requirements of CSA 

B415.1-10, clauses 8.5.7 and 10.4.3(h). 
Page 292 of 326

12.5.1.3.5 Record the test run time per the requirements of CSA B415.1-10, 

clause 10.4.3(a). 

12.5.1.3.6 Record and document all settings and adjustments, if any, made to the 

boiler/heater as recommended/required by manufacturer’s instruction manual for 

different combustion conditions or heat loads. These may include temperature setpoints, 

under and over-fire air adjustment, or other adjustments that could be made by an 

operator to optimize or alter combustion. All such settings shall be included in the report 

for each test run. 

12.5.1.4 Monitor the average heat output rate on the load side of the heat 

exchanger based on water temperatures and flow. If the heat output rate over a 10 minute 

averaging period gets close to the upper or lower limit of the target range (±5 percent), 

adjust the water flow through the heat exchanger to compensate. Make changes as 

infrequently as possible while maintaining the target heat output rate. The first test run 

shall be conducted at the Category IV heat output rate to validate that the appliance is 

capable of producing the manufacturer’s rated heat output capacity. 

12.5.2 Test Fuel Charge Adjustment. It is acceptable to adjust the test fuel charge 

(i.e., reposition) once during a test run if more than 60 percent of the initial test fuel 

charge weight has been consumed and more than 10 minutes have elapsed without a 

measurable (1 lb or 0.5 kg ) weight change while the operating control is in the demand 

mode. The time used to make this adjustment shall be less than 60 seconds. 

12.5.3 Test Run Completion. For the Category III and IV, “hot-to-hot” test runs, 

the test run is completed when the remaining weight of the test fuel charge is 0.0 lb (0.0 
Page 293 of 326

kg). (WFuelBurned = Wfuel) End the test run when the scale has indicated a test fuel charge 

weight of 0.0 lb (0.0 kg) or less for 30 seconds. 

For the Category I and II “cold-to-cold” test runs, the test run is completed; and 

the end of a test is defined at the first occurrence of any one of the following: 

(a) The remaining weight of the test fuel charge is less than 1 percent of the 

total test fuel weight (WFuelBurned > 0.99 ∙ Wfuel);

(b) The automatic control system on the boiler/heater switches to an off mode. 

In this case, the boiler/heater fan (if used) is typically stopped and all air flow dampers 

are closed by the control system. Note that this off mode cannot be an “overheat” or 

emergency shutdown which typically requires a manual reset; or

(c) If the boiler/heater does not have an automatic off mode: After 90 percent 

of the fuel load has been consumed and the scale has indicated a rate of change of the test 

fuel charge of less than 1.0 lb/hr for a period of 10 minutes or longer. Note - this is not 

considered “stopped fuel combustion,” See section 12.5.6.1. 

12.5.3.1 At the end of the test run, stop the particulate sampling train and overall 

efficiency (SLM) measurements, and record the run time, and all final measurement 

values. 

12.5.3.2 At the end of the test run, continue to operate the storage tank 

destratification pump until the total volume pumped exceeds 1.5 times the tank volume. 

The maximum average of the top and bottom temperatures measured after this time may 

be taken as the average tank temperature at the end of the tests (TFSavg, See section 

13.1). The total volume pumped may be based on the nominal flow rate of the 

destratification pump (See section 9.6). 
Page 294 of 326

12.5.3.3 For the Category I and II test runs, there is a need to determine the 

energy content of the unburned fuel remaining in the chamber if the remaining mass in 

the chamber is greater than 1 percent of the test fuel weight. Following the completion of 

the test, as soon as safely practical, this remaining fuel is removed from the chamber, 

separated from the remaining ash and weighed. This separation could be implemented 

with a slotted “scoop” or similar tool. A 1⁄4 inch opening size in the separation tool shall 

be used to separate the ash and charcoal. This separated char is assigned a heating value 

of 12,500 Btu/lb. 

12.5.4 Heat Output Capacity Validation. The first test run must produce a heat 

output rate that is within 10 percent of the manufacturer’s rated heat output capacity 

(Category IV) throughout the test run and an average heat output rate within 5 percent of 

the manufacturer’s rated heat output capacity. If the appliance is not capable of producing 

a heat output within these limits, the manufacturer’s rated heat output capacity is 

considered not validated and testing is to be terminated. In such cases, the tests may be 

restarted using a lower heat output capacity if requested by the manufacturer. 

Alternatively, during the Category IV run, if the rated output cannot be maintained for a 

15 minute interval, the manufacturer may elect to reduce the rated output to match the 

test and complete the Category IV run on this basis. The target outputs for Categories I, 

II, and III shall then be recalculated based on this change in rated output capacity. 

12.5.5 Additional Test Runs. Using the manufacturer’s rated heat output capacity 

as a basis, conduct a test for additional heat output categories as specified in section 4.3. 

It is not required to run these tests in any particular order. 
Page 295 of 326

12.5.6 Alternative Heat Output Rate for Category I. If an appliance cannot be 

operated in the Category I heat output range due to stopped combustion, two test runs 

shall be conducted at heat output rates within Category II. When this is the case, the 

weightings for the weighted averages indicated in section 14.1.15 shall be the average of 

the Category I and II weighting’s and shall be applied to both Category II results. 

Appliances that are not capable of operation within Category II (<25 percent of 

maximum) cannot be evaluated by this test method. 

12.5.6.1 Stopped Fuel Combustion. Evidence that an appliance cannot be operated 

at a Category I heat output rate due to stopped fuel combustion shall include 

documentation of two or more attempts to operate the appliance in heat output rate 

Category I and fuel combustion has stopped prior to complete consumption of the test 

fuel charge. Stopped fuel combustion is evidenced when an elapsed time of 60 minutes or 

more has occurred without a measurable (1 lb or 0.5 kg) weight change in the test fuel 

charge while the appliance operating control is in the demand mode. Report the evidence 

and the reasoning used to determine that a test in heat output rate Category I cannot be 

achieved. For example, two unsuccessful attempts to operate at an output rate of 10 

percent of the rated output capacity are not sufficient evidence that heat output rate 

Category I cannot be achieved. 

12.5.7 Appliance Overheating. Appliances with their associated thermal storage 

shall be capable of operating in all heat output categories without overheating to be rated 

by this test method. Appliance overheating occurs when the rate of heat withdrawal from 

the appliance is lower than the rate of heat production when the unit control is in the idle 

mode. This condition results in the water in the appliance continuing to increase in 
Page 296 of 326

temperature well above the upper limit setting of the operating control. Evidence of 

overheating includes: 1 hour or more of appliance water temperature increase above the 

upper temperature set-point of the operating control, exceeding the temperature limit of a 

safety control device (independent from the operating control – typically requires manual 

reset), boiling water in a non-pressurized system or activation of a pressure or 

temperature relief valve in a pressurized system. 

12.5.8 Option to Eliminate Tests in Category II and III. Following successful 

completion of a test run in Category I, the manufacturer may eliminate the Category II 

and III tests. For the purpose of calculating the annual averages for particulates and 

efficiency, the values obtained in the Category I run shall be assumed to apply also to 

Category II and Category III. It is envisioned that this option would be applicable to 

systems which have sufficient thermal storage such that the fuel load in the Category I 

test can be completely consumed without the system reaching its upper operating 

temperature limit. In this case, the boiler/heater would likely be operating at maximum 

thermal output during the entire test and this output rate may be higher than the 

manufacturer’s rated heat output capacity. The Category II and III runs would then be the 

same as the Category I run. It may be assumed that the particulate emission values and 

efficiency values determined in the startup, steady-state, and end phases of Category I are 

applicable in Categories II and III, for the purpose of determining the annual averages in 

lb/mmBtu and g/MJ (See section 13). For the annual average in g/hr, the length of time 

for stored heat to be drawn from thermal storage shall be determined for the test load 

requirements of the respective category. 
Page 297 of 326

12.5.9 Modification to Measurement Procedure in EPA Method 28 WHH to 

Determine Emissions Separately During the Startup, Steady-State and End Phases. With 

one of the two particulate sampling trains used, filter changes shall be made at the end of 

the startup phase and the steady-state phase (See section 3.0). This shall be done to 

determine the particulate emission rate and particulate emission index for the startup, 

steady-state, and end phases individually. For this one train, the particulates measured 

during each of these three phases shall be added together to also determine the particulate 

emissions for the whole run. 

12.5.10 Modification to Measurement Procedure in EPA Method 28 WHH and 

the Standards Referenced therein on Averaging Period for Determination of Efficiency 

by the Stack Loss Method. The methods currently defined in Method 28 WHH allow 

averaging over 10-minute time periods for flue gas temperature, flue gas CO2, and flue 

gas CO for the determination of the efficiency with the stack loss method. However, 

under some cycling conditions the “on” period may be short relative to this 10-minute 

period. For this reason, during cycling operation the averaging period for these 

parameters may not be longer than the burner on period divided by 10. The averaging 

period need not be shorter than one minute. During the off period, under cycling 

operation, averaging periods as specified in EPA Method 28 WHH and the standards 

referenced therein, may be used. Where short averaging times are used, however, the 

averaging period for fuel consumption may still be at 10 minutes. This average wood 

consumption rate shall be applied to all of the smaller time intervals included. 

12.6 Additional Test Runs. The testing laboratory may conduct more than one test 

run in each of the heat output categories specified in section 4.3. If more than one test run 
Page 298 of 326

is conducted at a specified heat output rate, the results from at least two-thirds of the test 

runs in that heat output rate category shall be used in calculating the weighted average 

emission rate. The measurement data and results of all test runs shall be reported 

regardless of which values are used in calculating the weighted average emission rate. 

13.0 Calculation of Results 

13.1 Nomenclature. 

COs – Carbon monoxide measured in the dilution tunnel at arbitrary time in ppm dry 

basis. 

COg/min – Carbon monoxide emission rate in g/min. 

COT – Total carbon monoxide emission for the full test run in grams. 

CO_1 – Startup period carbon monoxide emissions in grams. 

CO_2 – Steady-state period carbon monoxide emission in grams. 

CO_3 – End period carbon monoxide emission in grams. 

ET – Total particulate emissions for the full test run as determined per EPA Method 28 

WHH and the standards referenced therein in grams. 

E1 – Startup period particulate emissions in grams. 

E2 – Steady-state period particulate emissions in grams. 

E3 – End period particulate emissions in grams. 

E1_g/kg – Startup period particulate emission index in grams per kg fuel. 

E2_g/kg – Steady-state period particulate emission index in grams per kg fuel. 

E3_g/kg – End period particulate emission index in grams per kg fuel. 

E1_g/hr – Startup period particulate emission rate in grams per hour. 

E2_g/hr – Steady-state period particulate emission rate in grams per hour. 
Page 299 of 326

E3_g/hr – End period particulate emission rate in grams per hour. 

Eg/MJ – Emission rate in grams per MJ of heat output. 

Elb/mmBtu output – Emissions rate in pounds per million Btu of heat output. 

Eg/kg – Emissions factor in grams per kilogram of dry fuel burned. 

Eg/hr – Emission factor in grams per hour. 

HHV – Higher heating value of fuel = 8600 Btu/lb (19.990 MJ/kg). 

LHV – Lower heating value of fuel = 7988 Btu/lb (18.567 MJ/kg). 

ΔT – Temperature difference between cooling water entering and exiting the heat 

exchanger. 

Qout − Total heat output in Btu (MJ). 

Qin − Total heat input available in test fuel charge in Btu’s (MJ). 

Qstd – Volumetric flow rate in dilution tunnel in dscfm. 

M − Mass flow rate of water in lb/min (kg/min). 

Vi – Volume of water indicated by a totalizing flow meter at the ith reading in gallons 

(liters). 

Vf – Volumetric flow rate of water in heat exchange system in gallons per minute 

(liters/min). 

Θ – Total length of burn period in hours (Θ1+ Θ2+ Θ3). 

Θ1 – Length of time of the startup period in hours. 

Θ2 – Length of time of the steady-state period in hours. 

Θ3 – Length of time of the end period in hours.

Θ4 – Length of time for stored heat to be used following a burn period in hours. 

ti − Data sampling interval in minutes. 
Page 300 of 326

ηdel – Delivered heating efficiency in percent. 

Fi − Weighting factor for heat output category i. (See Table 2.)

T1 – Temperature of water at the inlet on the supply side of the heat exchanger, °F. 

T2 – Temperature of the water at the outlet on the supply side of the heat exchanger, °F. 

T3 – Temperature of cooling water at the inlet to the load side of the heat exchanger, °F. 

T4 – Temperature of cooling water at the outlet of the load side of the heat exchanger, °F. 

T5 – Temperature of the hot water supply as it leaves the boiler/heater, °F. 

T6 – Temperature of return water as it enters the boiler/heater, °F. 

T7 – Temperature in the boiler/heater optional destratification loop at the top of the 

boiler/heater, °F. 

T8 – Temperature in the boiler/heater optional destratification loop at the bottom of the 

boiler/heater, °F. 

TIavg − Average temperature of the appliance and water at start of the test. 

TIavg − (T5 + T6)/2 at the start of the test, °F. Eq. 1 

TFavg – Average temperature of the appliance and water at the end of the test. 

TFavg − (T5 + T6)/2 at the end of the test, °F. Eq. 2 

TIS1 − Temperature at the inlet to the storage system at the start of the test. 

TIS2 − Temperature at the outlet from the storage system at the start of the test. 

TFS1 − Temperature at the inlet to the storage system at the end of the test. 

TFS2 − Temperature at the outlet from the storage system at the end of the test. 

TISavg − Average temperature of the storage system at the start of the test. 

TISavg − (TIS1 + TIS2)/2 at the end of the test. Eq. 3 

TFSavg − Average temperature of the storage system at the end of the test. 
Page 301 of 326

TFSavg − (TFS1 + TFS2)/2. Eq. 4 

MC – Fuel moisture content in percent dry basis. 

σ – Density of water in pounds per gallon. 

σInitial – Density of water in the boiler/heater system at the start of the test in pounds per 

gallons. 

σboiler/heater – Density of water in the boiler/heater system at an arbitrary time during the 

test in pounds per gallon. 

Cp – Specific heat of water in Btu /lb, °F. 

Csteel − Specific heat of steel (0.1 Btu/ lb, oF). 

Vboiler/heater – total volume of water in the boiler/heater system on the weight scale in 

gallons. 

Wfuel – Fuel charge weight, as-fired or “wet”, in pounds (kg). 

Wfuel_1 − Fuel consumed during the startup period in pounds (kg). 

Wfuel_2 – Fuel consumed during the steady state period in pounds (kg). 

Wfuel_3 – Fuel consumed during the end period in pounds (kg). 

WFuelBurned – Weight of fuel that has been burned from the start of the test to an arbitrary 

time, including the needed correction for the change in density and weight of the water in 

the boiler/heater system on the scale in pounds (kg). 

WRemainingFuel – Weight of unburned fuel separated from the ash at the end of a test. Useful 

only for Category I and Category II tests. 

Wapp − Weight of empty appliance in pounds (kg). 

Wwat – Weight of water in supply side of the system in pounds (kg). 
Page 302 of 326

WScaleInitial – Weight reading on the scale at the start of the test, just after the test load has 

been added in pounds (kg). 

WScale – Reading of the weight scale at an arbitrary time during the test run in pounds 

(kg). 

WStorageTank − Weight of the storage tank empty in pounds (kg). 

WWaterStorage − Weight of the water in the storage tank at TISavg in pounds (kg). 

13.2 After the test is completed, determine the particulate emissions ET in 

accordance with EPA Method 28 WHH and the standards referenced therein. 

13.3 Determination of the weight of fuel that has been burned at an arbitrary time 

For the purpose of tracking the consumption of the test fuel load during a test run 

the following may be used to calculate the weight of fuel that burned since the start of the 

test: 

WFuelBurned = (WScaleInitial – WScale) + VBoiler/heater ∙ (σInitial – σboiler/heater) Eq. 5

Water density, σ, is calculated using Equation 12. 

13.4 Determine Average Fuel Load Moisture Content. 

MC = ∑ WSliceWet_i – MCSlice_i Eq. 6

∑ WSliceWet_i

13.5 Determine Heat Input. 

Qin = (Wfuel/(1+(MC/100))) x HHV, Btu (MJ). Eq. 7 

Qin LHV = (Wfuel/(1+(MC/100))) x LHV, Btu (MJ). Eq. 8 

13.5.1 Correction to Qin for the Category I and II tests, where there is greater than 

1 percent of the test fuel charge in the chamber at the end of the test period. 

QInCorrected = Qin – WRemaining ∙ 12,500 Btu Eq. 9 

 lb 

13.6 Determine Heat Output, Efficiency, and Emissions. 
Page 303 of 326

13.6.1 Determine heat output as: 

Qout = Σ [Heat output determined for each sampling time interval] + Change in heat stored 

in the appliance + Change in heat in storage tank. 

Qout = Σ[Cpi ∙Δ Ti ∙ Mi ∙ ti] + (Wapp ∙ Csteel + Wwater ∙ Cpa) ∙ (TFavg – TIavg) 

+ (WStorageTank ∙ Csteel + WWaterStorage ∙ Cpa) ∙ (TFSavg – TISavg) Btu (MJ) Eq. 10

Note: The subscript (i) indicates the parameter value for sampling time interval ti. 

Mi = Mass flow rate = gal/min x density of water (lb/gal) = lb/min. 

Mi=Vfi · σi, lb/min. Eq. 11 

σ i = (62.56 + ( -.0003413 x T3i ) + ( -.00006225 x T3i

2

)) 0.1337, lb/gal. Eq. 12

Cp = 1.0014 + ( -.000003485 x T3i ) Btu/lb, -oF. Eq. 13 

Csteel = 0.1 Btu/lb, -oF. 

Cpa = 1.0014 + (-.000003485 X (TIavg +TFavg)/2), Btu/lb, oF. Eq. 14

Vfi = (Vi –Vi-1)/(ti-ti-1), gal/min. Eq. 15 

Note: Vi is the total water volume at the end of interval i and Vi-1 is the total water 

volume at the beginning of the time interval. This calculation is necessary when a 

totalizing type water meter is used. 

13.6.2 Determine Heat Output Rate Over Burn Period (Θ1+ Θ2+ Θ3) as: 

Heat Output Rate = Qout/Θ, Btu/hr (MJ/hr). Eq. 16 

13.6.3 Determine Emission Rates and Emission Factors as: 

Eg/MJ = ET/(Qout x 0.001055), g/MJ. Eq. 17 

Elb/MM Btu output = (ET/453.59)/(Qout x 10-6), lb/mmBtu out. Eq. 18 

Eg/kg = ET/(Wfuel/(1+MC/100)), g/dry kg. Eq. 19 

Eg/hr = ET/(Θ1+ Θ2+ Θ3+ Θ4), g/hr. Eq. 20 

Θ4= (WStorageTank ∙ Csteel + WWaterStorage ∙ Cpa) ∙ (TFSavg – TISavg)/(Qout /Θ) Eq. 21
Page 304 of 326

If thermal storage is not used in a Category III or IV run, then Θ4 = 0 

E1_g/kg = E1/(Wfuel_1/(1+MC/100)), g/dry kg.

E2_g/kg = E2/(Wfuel_2/(1+MC/100)), g/dry kg.

E3_g/kg = E3/(Wfuel_3/(1+MC/100)), g/dry kg.

E1_g/hr = E1/Θ1, g/hr.

E2_g/hr = E2/Θ2, g/hr.

E3_g/hr = E3/Θ3, g/hr.

13.6.4 Determine delivered efficiency as: 

ηdel = (Qout/QInCorrected) x 100, %. Eq. 22 

ηdel LHV = (Qout/Qin LHV) x 100, %. Eq. 23 

13.6.5 Determine ηSLM - Overall Efficiency, also known as Stack Loss Efficiency, 

using stack loss method (SLM). 

For determination of the average overall thermal efficiency (ηSLM) for the test run, 

use the data collected over the full test run and the calculations in accordance with CSA 

B415.1-10, clause 13.7 except for 13.7.2(e), (f), (g), and (h), use the following average 

fuel properties for oak: %C = 50.0, %H = 6.6, %O = 43.2, %Ash = 0.2. 

13.6.5.1 Whenever the CSA B415.1-10 overall efficiency is found to be lower 

than the overall efficiency based on load side measurements, as determined by Eq. 22 of 

this method, section 14.1.7 of the test report must include a discussion of the reasons for 

this result. For a test where the CSA B415.1-10 overall efficiency SLM is less than 2 

percentage points lower than the overall efficiency based on load side measurements, the 

efficiency based on load side measurements shall be considered invalid. [Note on the 

rationale for the 2 percentage points limit. The SLM method does not include 

boiler/heater jacket losses and, for this reason, should provide an efficiency which is 
Page 305 of 326

actually higher than the efficiency based on the energy input and output measurements or 

“delivered efficiency.” A delivered efficiency that is higher than the efficiency based on 

the SLM could be considered suspect. A delivered efficiency greater than 2 percentage 

points higher than the efficiency based on the SLM, then, clearly indicates a 

measurement error.] 

13.6.6 Carbon Monoxide Emissions 

For each minute of the test period, the carbon monoxide emission rate shall be 

calculated as: 

COg/min = Qstd ∙ COs ∙ 3.30x10-5 Eq. 24 

Total CO emissions for each of the three test periods (CO_1, CO_2, CO_3) shall be 

calculated as the sum of the emission rates for each of the 1-minute intervals. 

Total CO emission for the test run, COT, shall be calculated as the sum of CO_1, CO_2, 

and CO_3. 

13.7 Weighted Average Emissions and Efficiency. 

13.7.1 Determine the weighted average emission rate and delivered efficiency 

from the individual tests in the specified heat output categories. The weighting factors 

(Fi) are derived from an analysis of ASHRAE bin data which provides details of normal 

building heating requirements in terms of percent of design capacity and time in a 

particular capacity range – or “bin” – over the course of a heating season. The values 

used in this method represent an average of data from several cities located in the 

northern United States. 

Weighted average delivered efficiency: ηavg = Σ ηi x Fi, %. Eq. 25 

Weighted average emissions: Eavg = Σ Ei x Fi, % Eq. 26 
Page 306 of 326

If, as discussed in section 12.5.8, the option to eliminate tests in Category II and 

III is elected, the values of efficiency and particulate emission rate as measured in 

Category I, shall be assigned also to Category II and III for the purpose of determining 

the annual averages. 

14.0 Report 

14.1.1 The report shall include the following: 

14.1.2 Name and location of the laboratory conducting the test. 

14.1.3 A description of the appliance tested and its condition, date of receipt and 

dates of tests. 

14.1.4 A description of the minimum amount of external thermal storage that is 

required for use with this system. This shall be specified both in terms of volume in 

gallons and stored energy content in Btu with a storage temperature ranging from 125°F 

to the manufacturer’s specified setpoint temperature. 

14.1.5. A statement that the test results apply only to the specific appliance tested. 

14.1.6 A statement that the test report shall not be reproduced except in full, 

without the written approval of the laboratory. 

14.1.7 A description of the test procedures and test equipment including a 

schematic or other drawing showing the location of all required test equipment. Also, a 

description of test fuel sourcing, handling and storage practices shall be included. 

14.1.8 Details of deviations from, additions to or exclusions from the test method, 

and their data quality implications on the test results (if any), as well as information on 

specific test conditions, such as environmental conditions. 

14.1.9 A list of participants and their roles and observers present for the tests. 
Page 307 of 326

14.1.10 Data and drawings indicating the fire box size and location of the fuel 

charge. 

14.1.11 Drawings and calculations used to determine firebox volume. 

14.1.12 Information for each test run fuel charge including piece size, moisture 

content and weight. 

14.1.13 All required data and applicable blanks for each test run shall be provided 

in spreadsheet format both in the printed report and in a computer file such that the data 

can be easily analyzed and calculations easily verified. Formulas used for all calculations 

shall be accessible for review. 

14.1.14 For each test run, Θ1,Θ2, Θ3, the total CO and particulate emission for 

each of these three periods, and Θ4. 

14.1.15 Calculated results for delivered efficiency at each heat output rate and the 

weighted average emissions reported as total emissions in grams, pounds per mm Btu of 

delivered heat, grams per MJ of delivered heat, grams per kilogram of dry fuel and grams 

per hour. Results shall be reported for each heat output category and the weighted 

average. 

14.1.16 Tables 1A, 1B, 1C, 1D, 1E and Table 2 must be used for presentation of 

results in test reports. 

14.1.17 A statement of the estimated uncertainty of measurement of the emissions 

and efficiency test results. 

14.1.18 A plot of CO emission rate in grams/minute vs. time, based on 1 minute 

averages, for the entire test period, for each run. 
Page 308 of 326

14.1.19 A plot of estimated boiler/heater energy release rate in Btu/hr based on 10 

minute averages, for the entire test period, for each run. This will be calculated from the 

fuel used, the wood heating value and moisture content, and the SLM efficiency during 

each 10 minute period. 

14.1.20 Raw data, calibration records, and other relevant documentation shall be 

retained by the laboratory for a minimum of 7 years. 

15.0 Precision and Bias 

15.1 Precision − It is not possible to specify the precision of the procedure in this 

test method because the appliance operation and fueling protocols and the appliances 

themselves produce variable amounts of emissions and cannot be used to determine 

reproducibility or repeatability of this test method.

15.2 Bias − No definitive information can be presented on the bias of the 

procedure in this test method for measuring solid fuel burning hydronic heater emissions 

because no material having an accepted reference value is available. 

16.0 Keywords 

16.1 Solid fuel, hydronic heating appliances, wood-burning hydronic heaters, 

partial thermal storage. 
Page 309 of 326

Table 1A. Data Summary Part A

Θ Wfuel MCave Qin Qout

Category

Run 

No

Load % 

Capacity

Target 

Load

Actual 

Load

Actual 

Load 

Test 

Duration

Wood 

Weight 

as-fired

Wood 

Moisture

Heat 

Input

Heat 

Output

Btu/hr Btu/

hr

Btu/

hr

% of 

max hrs lb %DB Btu Btu

I

< 15% of 

max

II

16-24% of 

max

III

25-50% of 

max

IV

Max 

capacity

Table 1B. Data Summary Part B 

T2 

Min ET E E Eg/hr Eg/kg ηdel ΗSLM

Category

Run 

No

Load % 

Capacity

Min 

Return 

Water 

Temp.

Total PM 

Emissions

PM 

Output 

Based

PM 

Output 

Based

PM 

Rate

PM 

Factor

Delivered 

Efficiency

Stack 

Loss 

Efficiency

°F g

lb/mm 

Btu Out g/MJ g/hr g/kg % %

I < 15% of 

max

II 16-24% 

of max

III 25-50% 

of max

IV Max 

capacity
Page 310 of 326

Table 1C. Data Summary Part C 

Θ1 Θ2 Θ3 CO_1 CO_2 CO_3 COT

Category

Run 

No

Load % 

Capacity

Startup 

Time. 

Steady 

State 

Time

End 

Time

Startup 

CO 

emission

Steady 

State CO 

emission

End CO 

emission

Total CO 

emission

min min min g g g g

I < 15% of 

max

II 16-24% of 

max

III 25-50% of 

max

IV Max 

capacity
Page 311 of 326

Table 1D. Data Summary Part D 

E1 E2 E3 E1_g/kg E2_g/kg E3_g/kg

Category

Run 

No

Load % 

Capacity

Startup 

PM 

Steady 

State PM End PM

Startup 

PM 

emission 

index

Steady 

State PM 

emission

index

End PM 

emission 

index

g g g g/kg fuel g/kg fuel g/kg fuel 

I < 15% of 

max

II 16-24% of 

max

III 25-50% of 

max

IV Max 

capacity
Page 312 of 326

Table 1E: Label Summary Information 

MANUFACTURER:

MODEL NUMBER:

ANNUAL EFFICIENCY RATING: ηavg (Using higher heating value)

PARTICLE EMISSIONS: Eavg grams/hr (Average)

lbs/mmBtu/hr Output

Table 2. Annual Weighting 

Category Weighting 

Factor (Fi)

ηdel,i x Fi Eg/MJ,i x Fi Eg/kg,i x Fi Elb/mmBtu Out,i x Fi Eg/hr,i x Fi

I 0.437

II 0.238

III 0.275

IV 0.050

Totals 1.000
Page 313 of 326

Figure 1. Schematic of Equipment Test Setup
Page 314 of 326

Figure 2. Schematic of Test Equipment Set-up

Note: Illustrated appliance pump location and flow path through the appliance.

2.28. Part 60 is amended by revising Appendix I to read as follows:

Appendix I to Part 60—Owner's Manuals and Temporary Labels for Wood Heaters 

Subject to Subparts AAA and QQQQ of Part 60

1. Introduction

The purpose of this appendix is to provide specific instructions and examples to

manufacturers for compliance with the owner's manual provisions of subparts AAA and 

QQQQ of this part.

2. Instructions for Preparation of Wood Heater Owner's Manuals

2.1 Introduction
Page 315 of 326

Although the owner's manuals do not require premarket approval, EPA will 

monitor the contents to ensure that sufficient information is included to provide heater 

proper operation and maintenance information affecting emissions to consumers. The 

manufacturer must make current and historical owner’s manuals available on the 

company web site and upon request to the EPA. The purpose of this section is to provide 

instructions to manufacturers for compliance with the owner's manual provisions of § 

60.536(g) of subpart AAA that applies to wood heaters and § 60.5478(g) of subpart 

QQQQ that applies to hydronic heaters and forced-air furnaces. A checklist of topics and 

illustrative language is provided as instructions. Owner's manuals should be tailored to 

specific wood heater models, as appropriate.

2.2 Topics Required To Be Addressed in Owner's Manual

(a) Wood heater description and compliance status;

(b) Tamper warnings;

(c) Overall heater warranty information and catalyst information and warranty (if 

catalyst-equipped);

(d) Fuel selection;

(e) Achieving and maintaining catalyst light-off (if catalyst-equipped);

(f) Catalyst monitoring (if catalyst-equipped);

(g) Troubleshooting catalytic-equipped heaters (if catalyst-equipped);

(h) Catalyst replacement (if catalyst-equipped);

(i) Wood heater proper operation and maintenance, including minimizing visible 

emissions;
Page 316 of 326

(j) Wood heater proper installation, including location, stack height and achieving 

proper draft;

(k) Use of smoke detectors and carbon monoxide monitors; and 

(l) Efficiency.

2.3 Sample Text/Descriptions

(a) The following are example texts and/or further descriptions illustrating the 

topics identified above. Although the regulation requires manufacturers to address (where 

applicable) the 10 topics identified above, the exact language is not specified. Manuals 

should be written specific to the model and design of the wood heater. The following 

instructions are composed of generic descriptions and texts. 

(b) If manufacturers choose to use the language provided in the example, the 

portion in italics should be revised as appropriate. Any manufacturer electing to use the 

EPA example language will be considered to be in compliance with owner's manual 

requirements provided that the particular language is printed in full with only such 

changes as are necessary to ensure accuracy. 

Example language is not provided for certain topics, since these areas are 

generally heater specific. For these topics, manufacturers should develop text that is 

specific to the proper operation and maintenance of their particular products.

2.3.1 Wood Heater Description and Compliance Status

Owner's manuals must include:

(a) Manufacturer and model;
Page 317 of 326

(b) Compliance status (2015 standard, 2016 standard, 2017 standard, 2020 

standard, crib wood standard or cord wood alternative standard, last allowable sell date, 

etc.); and

(c) Heat output range.

Exhibit 1—Example Text covering (a), (b), and (c) above:

“This manual describes the installation and operation of the Brand X, Model 0 

catalytic equipped wood heater. This heater meets the 2015 U.S. Environmental 

Protection Agency's crib wood emission limits for wood heaters sold after [INSERT 

DATE 60 DAYS AFTER DATE OF PUBLICATION IN THE FEDERAL 

REGISTER]. Under specific test conditions this heater has been shown to deliver heat at 

rates ranging from 8,000 to 35,000 Btu/hr.”

2.3.2 Tamper Warnings

The following statement must be included in the owner's manual for all units:

“This wood heater has a manufacturer-set minimum low burn rate that must not 

be altered. It is against federal regulations to alter this setting or otherwise operate this 

wood heater in a manner inconsistent with operating instructions in this manual.”

The following statement must be included in the owner's manual for catalystequipped units:

“This wood heater contains a catalytic combustor, which needs periodic 

inspection and replacement for proper operation. It is against federal regulations to 

operate this wood heater in a manner inconsistent with operating instructions in this 

manual, or if the catalytic element is deactivated or removed.”
Page 318 of 326

2.3.3 Overall Heater Warranty Information and Catalyst Information and 

Warranty (if catalyst-equipped)

The following information must be included with or supplied in the owner's and 

warranty manuals:

(a) Manufacturer and model, including catalyst if catalyst-equipped;

(b) Warranty details, including catalyst if catalyst-equipped; and

(c) Instructions for warranty claims.

Exhibit 2—Example Text covering (a), (b), and (c) for catalysts:

“The combustor supplied with this heater is a Brand Z, Long Life Combustor. 

Consult the catalytic combustor warranty also supplied with this wood heater. Warranty 

claims should be addressed to:

Stove or Catalyst Manufacturer____________________

Address____________________

Phone #____________________”

2.3.3.1 This section should also provide clear instructions on how to exercise the 

warranty (how to package parts for return shipment, etc.).

2.3.4 Fuel Selection

Owner's manuals must include:

(a) Instructions on acceptable fuels;

(b) Warning against inappropriate fuels; and

(c) How to determine seasoned wood compared to unseasoned wood, how to use 

moisture meters and other techniques and the importance of seasoned wood.

Exhibit 3—Example Text covering (a) and (b):
Page 319 of 326

“This heater is designed to burn natural wood only. Higher efficiencies and lower 

emissions generally result when burning air dried seasoned hardwoods, as compared to 

softwoods or to green or freshly cut hardwoods. DO NOT BURN:

(1) Garbage;

(2) Lawn clippings or yard waste;

(3) Materials containing rubber, including tires;

(4) Materials containing plastic;

(5) Waste petroleum products, paints or paint thinners, or asphalt products;

(6) Materials containing asbestos;

(7) Construction or demolition debris;

(8) Railroad ties or pressure-treated wood;

(9) Manure or animal remains; 

(10) Salt water driftwood or other previously salt water saturated materials;

(11) Unseasoned wood; or

(12) Paper products, cardboard, plywood, or particleboard. The prohibition 

against burning these materials does not prohibit the use of fire starters made from paper, 

cardboard, saw dust, wax and similar substances for the purpose of starting a fire in an 

affected wood heater.

Burning these materials may result in release of toxic fumes or render the heater 

ineffective and cause smoke.”

2.3.5 Achieving and Maintaining Catalyst Light-Off

Owner's manuals must describe in detail proper procedures for:

(a) Operation of catalyst bypass (stove specific);
Page 320 of 326

(b) Achieving catalyst light-off from a cold start; and

(c) Achieving catalyst light-off when refueling.

2.3.5.1 No example text is supplied for describing operation of catalyst bypass 

mechanisms (Item (a) above) since these are typically stove-specific. Manufacturers must 

provide instructions specific to their model describing:

(1) Bypass position during startup;

(2) Bypass position during normal operation; and

(3) Bypass position during reloading.

Exhibit 4—Example Text for Item (b):

“The temperature in the stove and the gases entering the combustor must be raised 

to between 500° to 700°F for catalytic activity to be initiated. During the startup of a cold 

stove, a medium to high firing rate must be maintained for about 20 minutes. This 

ensures that the stove, catalyst, and fuel are all stabilized at proper operating 

temperatures. Even though it is possible to have gas temperatures reach 600°F within 2 to 

3 minutes after a fire is started, if the fire is allowed to die down immediately, it may go 

out or the combustor may stop working. Once the combustor starts working, heat 

generated in it by burning the smoke will keep it working.”

Exhibit 5—Example Text for Item (c):

“REFUELING: During the refueling and rekindling of a cool fire, or a fire that 

has burned down to the charcoal phase, operate the stove at a medium to high firing rate 

for about 10 minutes to ensure that the catalyst reaches approximately 600°F.”

2.3.6 Catalyst Monitoring

Owner's manuals must include:
Page 321 of 326

(a) Recommendation to visually inspect combustor at least three times during the 

heating season;

(b) Discussion on expected combustor temperatures for monitor-equipped units; 

and

(c) Suggested monitoring and inspection techniques and importance of ensuring 

catalyst is operating properly.

Exhibit 6—Example Text covering (a), (b) and (c):

“It is important to periodically monitor the operation of the catalytic combustor to 

ensure that it is functioning properly and to determine when it needs to be replaced. A 

non-functioning combustor will result in a loss of heating efficiency, and an increase in 

creosote and emissions. Following is a list of items that should be checked on a periodic 

basis:

• Combustors should be visually inspected at least three times during the heating 

season to determine if physical degradation has occurred. Actual removal of the 

combustor is not recommended unless more detailed inspection is warranted because of 

decreased performance. If any of these conditions exists, refer to Catalyst 

Troubleshooting section of this owner's manual.

• This catalytic (or hybrid) heater is equipped with a temperature probe to monitor 

catalyst operation. Properly functioning combustors typically maintain temperatures in 

excess of 500°F, and often reach temperatures in excess of 1,000°F. If catalyst 

temperatures are not in excess of 500°F, refer to Catalyst Troubleshooting section of this 

owner's manual.
Page 322 of 326

• You can get an indication of whether the catalyst is working by comparing the 

amount of smoke leaving the chimney when the smoke is going through the combustor 

and catalyst light-off has been achieved, to the amount of smoke leaving the chimney 

when the smoke is not routed through the combustor (bypass mode).

Step 1—Light stove in accordance with instructions in section 3.3.5. 

Step 2—With smoke routed through the catalyst, go outside and observe the 

emissions leaving the chimney.

Step 3—Engage the bypass mechanism and again observe the emissions leaving 

the chimney.

Significantly more smoke will be seen when the exhaust is not routed through the 

combustor (bypass mode).”

2.3.7 Catalyst Troubleshooting

The owner's manual must provide clear descriptions of symptoms and remedies to 

common combustor problems and importance. It is recommended that photographs of 

catalyst peeling, plugging, thermal cracking, mechanical cracking, and masking be 

included in the manual to aid the consumer in identifying problems and to provide 

direction for corrective action.

2.3.8 Catalyst Replacement

The owner's manual must provide clear step-by-step instructions on how to 

remove and replace the catalytic combustor. The section should include diagrams and/or 

photographs.

2.3.9 Wood Heater Proper Operation and Maintenance
Page 323 of 326

The owner's manual must provide clear descriptions of symptoms and remedies to 

common heater problems and importance. The owner’s manual information must be 

adequate to enable consumers to achieve optimal emissions performance. Such 

information must be consistent with the operating instructions provided by the 

manufacturer to the approved test laboratory for operating the wood heater during 

certification testing, except for details of the certification test that would not be relevant 

to the user. 

Owner's manual must include:

(a) Recommendations about building and maintaining a fire, especially for cold 

starts and the effectiveness of the top-down approach for starting fires;

(b) Instruction on proper use of air controls, including how to establish good 

combustion and how to ensure good combustion at the lowest burn rate for which the 

heater is warranted;

(c) Ash removal and disposal;

(d) Instruction replacement of gaskets, air tubes and other parts that are critical to 

the emissions performance of the unit, and other maintenance and repair instructions;

(e) Warning against overfiring; and

(f) Suggested monitoring and inspection techniques and importance of ensuring 

heater is operating properly, including ensuring visible emissions are minimized.

2.3.9.1 No example text is supplied for (a), (b), (d) and (f) since these items are 

model specific. Manufacturers should provide detailed instructions on building and 

maintaining a fire including selection of fuel pieces, fuel quantity and stacking 

arrangement. Manufacturers should also provide instruction on proper air settings (both 
Page 324 of 326

primary and secondary) for attaining minimum and maximum heat outputs and any 

special instructions for operating thermostatic controls. Step-by-step instructions on 

inspection and replacement of gaskets should also be included. Manufacturers should 

provide diagrams and/or photographs to assist the consumer. Gasket type and size should 

be specified.

Exhibit 7—Example Text for Item (c):

“Whenever ashes get 3 to 4 inches deep in your firebox or ash pan, and when the 

fire has burned down and cooled, remove excess ashes. Leave an ash bed approximately 

1 inch deep on the firebox bottom to help maintain a hot charcoal bed.”

“Ashes should be placed in a metal container with a tight-fitting lid. The closed container 

of ashes should be placed on a noncombustible floor or on the ground, away from all 

combustible materials, pending final disposal. The ashes should be retained in the closed 

container until all cinders have thoroughly cooled.”

Exhibit 8—Example Text covering Item (e):

“DO NOT OVERFIRE THIS HEATER”

“Attempts to achieve heat output rates that exceed heater design specifications 

can result in permanent damage to the heater and to the catalytic combustor if so 

equipped.”

2.3.10 Wood Heater Installation, Including Stack Height, Heater Locations and 

Achieving Proper Draft

Owner's manual must include:

(a) Importance of proper draft;

(b) Conditions indicating inadequate draft;
Page 325 of 326

(c) Conditions indicating excessive draft; and

(d) Guidance on proper stack height and proper heater locations, i.e., not too close 

to neighbors or in valleys that would cause unhealthy air quality or nuisance conditions.

2,3,10.1 No example text is supplied for (d) because state, local and tribal 

requirements are model and location specific. 

Exhibit 9—Example Text for Item (a):

“Draft is the force which moves air from the appliance up through the chimney. 

The amount of draft in your chimney depends on the length of the chimney, local 

geography, nearby obstructions and other factors. Too much draft may cause excessive 

temperatures in the appliance and may damage the catalytic combustor. Inadequate draft 

may cause backpuffing into the room and ‘plugging’ of the chimney or the catalyst.” 

Exhibit 10—Example Text for Item (b):

“Inadequate draft will cause the appliance to leak smoke into the room through 

appliance and chimney connector joints.”

Exhibit 11—Example Text for Item (c):

“An uncontrollable burn or excessive temperature indicates excessive draft.” 

2.3.11. Efficiency

Owner’s manual must include:

(a) Description of how the efficiency was determined, e.g., use higher heating value 

of the fuel instead of lower heating value of the fuel, discuss sweet spot versus annual 

average versus annual fuel usage efficiency (AFUE);

(b) How operation and fuels affect efficiency, e.g., seasoned wood versus high 

moisture fuel; operation at sweet spot versus low-burn rates; and
Page 326 of 326

(c) How location affects the efficiency, e.g., in main living area versus basement 

versus outdoors in sub-freezing temperatures.

2.3.12. Smoke and Carbon Monoxide Emissions and Monitors

Owner’s manual must include:

(a) Discussion of smoke and carbon monoxide (CO) emissions, including the CO 

data submitted in the certification application and expected variations for different 

operating conditions;

(b) Recommendation to have smoke monitors; and

(c) Recommendation to have monitors for areas that are expected to generate CO, 

e.g., heater fueling areas, pellet fuel bulk storage areas, sheds containing hydronic 

heaters. 

3. Instructions for Preparation of Wood Heater Temporary Labels

3.1 Temporary labels that show the values for emissions, efficiency, 

recommended heating area and the compliance status may (voluntarily) be affixed by the 

manufacturer to wood heaters that meet the 2020 particulate matter emission standards

early or that meet the cord wood alternative compliance options in subparts AAA and 

QQQQ of this part.

3.2 The seller of each heater covered by section 3.1 may ensure that the temporary 

label remains affixed until each heater is purchased by the end user.

3.3 The temporary label option for the 2020 particulate matter emission standards

end as of [INSERT DATE 60 DAYS PLUS 5 YEARS AFTER DATE OF 

PUBLICATION IN THE FEDERAL REGISTER].
Page 327 of 326

3.4 The template for the temporary labels will be supplied by the Administrator 

upon request.