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/R Incorporated Providing Environmental Technical Support Since 1989

501 Eastowne Dr., Suite 250  Chapel Hill, North Carolina 27514

Telephone: (919) 484-0222  Fax: (919) 484-0122

MEMORANDUM

DATE: November 10, 2014

SUBJECT: Derivation of wood heater model percentages meeting Step 2 standards

FROM: Jill Mozier, EC/R Inc.

TO: David Cole, EPA/OAQPS 

Gil Wood, EPA/OAQPS

Amanda Aldridge, EPA/OAQPS

The purpose of this memorandum is to document how we derived the percentage of wood 

heater appliances estimated to already meet the Step 2 standards effective in 2020. 

I. Non-Catalytic Wood Stoves

For our cost and emission calculations, we estimate that 18% of non-catalytic stove models 

already meet the 2020 Step 2 standard. To estimate this percentage of non-catalytic stoves 

emitting 2.0 g/hr or less (EPA weighted average emissions), we used HPBA’s 2010 wood heater 

database1 with the correction factor for method 5G removed, consistent with the final rule. This 

adjusted dataset is provided as an attachment to this memo and will be made available in the 

docket.2The dataset contains 110 non-catalytic stoves and 20 of these – or 18% – have an EPA 

weighted average emission of 2.0 g/hr or less.

II. Catalytic & Hybrid Wood Stoves

For our cost and emission calculations, we estimate that 89% of catalytic and hybrid stove 

models already meet the 2020 Step 2 standard. To estimate this percentage of catalytic and 

hybrid stoves emitting 2.0 g/hr or less (EPA weighted average emissions), we used data from 

EPA’s Office of Enforcement and Compliance Assurance (OECA) for wood stoves certified 

between 2010 and 20143 with the correction factor for method 5G removed, consistent with the 

final rule. This dataset is also provided as an attachment to this memo and will be make available 

in the docket.4The dataset contains 9 catalytic and other (presumably hybrid) stoves certified 

between 2010 and 2014 and 8 of these – or approximately 89% – have an EPA weighted average 

emission of 2.0 g/hr or less. 

 

1

Final HPBA Heater Database version 2/25/10, EC/R received from Bob Ferguson for HPBA on 4/26/10

2

Spreadsheet entitled HPBA dataset 5g correction factor removed_ECR version is submitted to EPA via e-mail 

along with this memo and will be included in the docket

3 The regularly-updated list of EPA certified wood heaters is available on OECA’s website at 

http://www.epa.gov/compliance/resources/publications/monitoring/caa/woodstoves/certifiedwood.pdf

4

Spreadsheet entitled New data NSPS sheet RT_ECR version is submitted to EPA via e-mail along with this memo 

and will be included in the docket
2

III. Non-Catalytic and Catalytic Wood Stoves Combined

For our cost and emission calculations, we estimate that 26% of non-catalytic and catalytic stove 

models combined already meet the 2020 Step 2 standard. We required a combined estimate 

because our shipment data (used for emission calculations) does not distinguish between 

catalytic and non-catalytic heaters. We used a weighted average to calculate the combined 

percentage meeting Step 2 based on industry data provided in their comment in response to the 

proposed rule. Specifically, Hearth, Patio and Barbecue Association’s (HPBA’s) economic 

consultant, NERA, estimated that in 2018 there would be approximately 100,000 wood stove 

sales and that 89,000 of these total woodstove sales would be non-catalytic while approximately

11,000 would be catalytic.5 Using a weighted average based on these sales projections from 

industry and assuming that 18% of non-catalytic and 89% of catalytic & hybrid stoves can meet 

Step 2 already (as explained above), we estimate that 26% of all wood stoves can meet the 2020 

Step 2 standard without additional R&D investment. 

IV. Pellet Stoves

For our cost and emission calculations, we estimate that 70% of pellet stove models already meet 

the 2020 Step 2 standard. To estimate this percentage of pellet stoves emitting 2.0 g/hr or less 

(EPA weighted average emissions), we used OECA data for wood stoves certified between 2010 

and 2014, adjusted by removal of the 5g correction factor, as explained above.6The dataset 

contains 27 pellet stoves certified between 2010 and 2014 and 19 of these – or 70% – have an 

EPA weighted average emission of 2.0 g/hr or less.

V. Hydronic Heaters

For our cost and emission calculations, we estimate that 18% of hydronic heater models already 

meet the 2020 Step 2 standard. We based this estimate on the fact that 9 of the 49 Phase 2 

qualified hydronic heater models – or 18% – emit 0.10 pounds of PM or less per million Btu heat 

output (lb/mmBtu) for each individual burn rate. This statistic is based on models qualified at 

Phase 2 under EPA’s Hydronic Heater’s Voluntary Program as of 10-23-2014.7

VI. Forced-Air Furnaces and Single Burn Rates Stoves

For our cost and emission calculations, we estimate that all forced-air furnace and single burn 

rate stove models will require investment in R&D in order to meet the 2020 Step 2 limits.

Forced-air furnace and single burn rate stove designs able to meet the Step 2 limits may be based 

on technology transferred from hydronic heater designs and/or wood stove designs.

 

5 Cost-Effectiveness Analysis of Alternative Woodstove New Source Performance Standards, prepared by NERA 

Economic Consulting, May 2014, p.7. Submitted as Attachment 2 from the Hearth, Patio and Barbeque 

Association’s Comment on the proposed rule to Docket EPA-HQ-OAR-2009-0734 available at 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OAR-2009-0734-1643. 

6

See footnotes 3 and 4.

7 A list of Phase 2 qualified hydronic heater models is available on EPA’s Burn Wise website at 

http://www.epa.gov/burnwise/owhhlist.html. A more detailed spreadsheet is also available in the docket and is 

entitled Hydronic Heater M28 Test Data