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Proposed New Source Performance Standards for New Residential Wood Heaters,

Residential Hydronic Heaters (Outdoor Wood Boilers or Indoor Wood Boilers),

Forced-Air Furnaces and Residential Masonry Heaters

BACKGROUND

 The U.S. Environmental Protection Agency (EPA) issued New Source Performance Standards (NSPS) for 

residential wood heaters in 1988. Those standards apply to adjustable burn rate wood stoves and will remain 

in effect until this proposal becomes a final rule, likely 1 year after proposal. 

 The 1988 standards were developed through a regulatory negotiation process that included representatives 

of the environmental community, consumer groups, state air pollution control and energy agencies, industry

and the EPA. 

 Wood smoke is made up of a mixture of gases and fine particles that are produced when wood and other 

organic matter burns. The fine particles in smoke – also called fine particle pollution or PM2.5 – can get deep 

into the lungs, harming both your lungs and your heart. People with heart or lung disease, older adults and 

children are the most at risk.

CURRENT ACTION

 The EPA is proposing amendments to its standards for new residential wood heaters that would strengthen 

its emissions standards for wood stoves, while establishing standards for outdoor and indoor wood boilers 

(also known as hydronic heaters) for the first time.

 The proposed standards would also set emission limits for new pellet stoves, wood-fired forced-air furnaces, 

masonry wood heaters and a type of previously unregulated woodstove known as a “single burn rate” stove. 

The proposed standards would not affect heaters that are fueled solely by oil, gas or coal.

 The proposal would not apply to woodstoves and other wood heating appliances currently in use in people’s 

homes.

 The proposed rule would significantly reduce emissions of fine particle pollution from newly manufactured 

stoves and other wood heating appliances. Emissions of volatile organic compounds, carbon monoxide, 

hazardous air pollutants and greenhouse gases also would drop as a result of the rule.

 In addition to being cleaner, the units would be more efficient than older ones, meaning homeowners will 

get more heat from the wood they burn.

 The EPA will take public comment on the proposal for 90 days after the proposed rule is published in the 

Federal Register. The agency is planning to hold two public hearings on the rule.

 Some of the regulatory options in the proposal have the potential for a significant economic impact on a

number of small entities. The EPA convened a Small Business Regulatory Enforcement Fairness Act panel 

on August 4, 2011. As a result of those conversations, this proposal incorporates reasonable time for all 

manufacturers to develop cleaner models by allowing a phased approach. In addition, this proposal includes 

additional time for small-volume manufacturers of some devices. 
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SUMMARY OF PROPOSED REQUIREMENTS

 The Clean Air Act requires the EPA to set NSPS for industrial categories that cause, or significantly 

contribute to, air pollution that may endanger public health or welfare. The law requires the EPA to review 

these standards every 8 years.

 Residential wood combustion is a significant source of fine particle pollution, emitting more than 

350,000 tons of fine particles in 2008, according to the EPA’s National Emissions Inventory. 

 The EPA is proposing that each type of new residential wood heater (except masonry heaters) meets PM 

emission limits in a two-step approach to require all manufacturers to make the improvements that can be 

done immediately, and also to provide manufacturers time for additional research and development (R&D) 

and testing to adapt to the best systems of emissions reduction. Under the proposed approach, manufacturers 

would need to meet Step 1 limits immediately upon promulgation and the final Step 2 emission limits 

5 years after promulgation. 

 In addition, the EPA is taking comment on a three-step approach (a longer compliance timeframe) to allow 

an interim Step 2 emissions level 3 years after promulgation, particularly for small manufacturers that may

need more time for R&D and testing before meeting the final Step 3 emission limit 8 years after 

promulgation. The EPA’s proposed Step 2 emission limit (5 years after promulgation) would be identical to 

the Step 3 emission limit (8 years after promulgation) for this other approach.

ANTICIPATED PUBLIC AND STAKEHOLDER RESPONSE

 State and local agencies are anxious to see these standards promulgated as soon as possible. Some states 

need these wood heater standards to help them meet their PM2.5 national ambient air quality standard

(NAAQS) requirements. The National Association of Clean Air Agencies, Western States Air Resources 

Council, Central States Air Resources Agencies, Lake Michigan Air Directors Consortium, Mid-Atlantic 

Regional Air Management Association, and Northeast States for Coordinated Air Use Management all

strongly support strengthened standards, especially removing the exemptions for single-burn-rate stoves and 

furnaces and adding stringent requirements on hydronic heaters. 

 Environmental groups strongly support strengthened standards overall and especially stringent limits on 

hydronic heaters because they emit a large volume of PM emissions and are negatively impacting the health 

and welfare of citizens across the country. 

 Most public feedback supports strong regulations, especially for hydronic heaters, which are considered a 

large nuisance for those living nearby these units. 

 Industry groups agree that standards are needed for hydronic heaters and forced-air furnaces and that it is 

appropriate to update the wood heater standards to the state of Washington levels. 

 Some industry groups question the cost effectiveness and potential economic impacts of some of the 

stronger proposed options.

 At least one fireplace manufacturer questions why the Agency is not proposing standards for new fireplaces.