EPA Docket Center
EPA West (Air Docket)
Attention Docket ID number:
U.S. Environmental Protection Agency
Mailcode: 2822T
1200 Pennsylvania Ave. NW
Washington, DC 20503
May 1, 2014
Dear Sir or Madame,
The Western States Air Resources (WESTAR Council, an association of 15 western
state air quality agencies, appreciates the opportunity to comment on the proposed Standards
of Performance for New Residential Wood Heaters, New Residential Hydronic Heaters and
Forced-Air Furnaces, and New Residential Masonry Heaters (NSPS). In some western
states, including Alaska, burning wood is the most economical and practical means for
residents to heat their homes, particularly in remote areas or communities with high energy
costs. Because of the importance of wood heating in these areas, it is critical that EPA’s
rulemaking provide a balance that allows for the continued economic use of wood heat while
making gains to reduce air pollutant emissions to levels safe to human health. The comments
that follow are the views of all the WESTAR member states, except South Dakota and
Alaska. Alaska concurs with portions of this letter particularly the proposals for Step 1,
developing testing methods and labeling devices. Alaska and some of the other WESTAR
member states will also be commenting separately on the proposal related to their state’s
unique needs and circumstances.
Since 2008, WESTAR has advocated for revisions to the NSPS to expand the scope of
appliances covered by the NSPS and tighten the standards for currently covered appliances.
We are pleased that EPA has proposed changes to existing regulations that will accomplish
both these objectives.
WESTAR believes that EPA should establish standards based on the Best System of
Emission Reduction (BSER) and that the standards should be implemented as expeditiously
as practicable. Residential wood heating appliances remain in homes for many years. It is
critically important that the public have ready access to the cleanest burning affordable
technology so that when they purchase a new or replacement appliance it meets a high level
of emission performance.
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This is particularly important in airsheds dominated by residential wood smoke that
may already have unhealthy air. State and local air quality management organizations are
required by the Clean Air Act to develop regulatory programs for these communities to
mitigate the adverse health consequences of residential wood heating. The alternatives are
often limited to curtailment programs when air quality deteriorates and stove change-out
programs to replace non-certified appliances with certified ones. In some areas temperature
inversions during the winter, when people rely most on wood to heat their homes, keeps wood
smoke close to the ground creating greater health risks from PM2.5. In the long run, a federal
appliance certification program is the most cost-effective method for reducing residential
wood heating pollution.
A growing body of evidence has demonstrated that particulate emissions from
residential wood combustion, among other sources, have significant health effects at lower
ambient concentrations than was apparent when the NSPS was first developed. Advances in
our understanding of the adverse health consequences of fine particulate has resulted in a
lower PM2.5 NAAQS standard and it could very well be that the future will see further
tightening of the PM2.5 NAAQS. Since the Residential Wood Heating NSPS was
promulgated in 1988, advances in residential wood burning technology make it possible for
these sources to contribute more to cleaning up airsheds across the country.
Some WESTAR states have long struggled with pollution from residential wood
combustion. Control strategies put in place over the years have enabled some areas to come
into compliance with the PM NAAQS. However, there are new areas for which control
programs for residential wood heating are under development to address violations of the
PM2.5 NAAQS. It is difficult, particularly without up-to-date NSPS, for local governments to
simultaneously address concerns that restrictions on wood burning will prevent some people
from being to economically heat their homes while assuring others that their health won’t be
impacted by PM2.5 concentrations where wood burning is more prevalent. The best solution is
cleaner burning appliances. In the absence of more stringent national standards, state air
quality agencies will continue to adopt more stringent measures than the current, but out-ofdate NSPS, including appliance testing and certification programs. A sufficiently stringent
uniform federal new appliance certification program will benefit manufacturers who
otherwise may need to make separate compliance demonstrations in more jurisdictions.
Finally, it will relieve a number of states and counties from the risk of Clean Air Act
sanctions and other adverse economic impacts relating to non-attainment.
The focus of our comments are on residential wood (room) heaters, the
implementation schedule and testing requirements, hydronic heater standards and some of the
labeling provisions. We are not commenting on the laboratory accreditation, or appliance
certification process. We will also not be commenting on masonry heaters as they are a
relatively small segment of the market.
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New Residential Wood Heaters
Wood Stoves and Fireplace Inserts
We recommend that instead of a ‘Step 1’ standard of 4.5 g/hr for variable heat output
stoves and fireplace inserts, EPA adopt the Washington State standard (4.5 g/hr non-catalytic,
2.5 catalytic 1). This standard has been in place since 1995 and many products currently meet
that standard. Additionally, we do not believe that currently certified new appliances with a
higher emission level should be grandfathered beyond the effective date of the standard.
We also recommend that EPA establish a more stringent ‘Step 2’ standard provided
certifiable stoves are available then at an affordable cost. And while we do not recommend a
specific emission limit (see test method discussion below), we believe a more stringent
standard should be put in place not longer than five years in the future as proposed by EPA.
The alternative three-step, eight-year implementation schedule is too long to wait for further
emission reductions and does not create the necessary incentives for the introduction of
cleaner burning appliances, particularly since EPA does not appear to be relying on
significant emission technology innovation. Additionally, as eight years is the statutory
schedule for reviewing the NSPS, it will not allow enough time for the more stringent
standards to take effect for EPA to evaluate their effectiveness.
Pellet Stoves
Some manufacturers of these appliances have enjoyed a competitive advantage in not
complying with the NSPS by creating devices with high air-to-fuel ratios. This exemption for
pellet stoves is an unintended consequence of what was intended to be a basis for excluding
fireplaces. Pellet stove manufacturers who have not certified their units have been competing
in the market with certified pellet stove manufacturers and cord wood heaters, without having
to comply with the NSPS requirements including certification testing, labeling, ongoing
quality assurance, etc. EPA is right in subjecting all pellet stoves to certification
These appliances, operating with a manufactured fuel and automated fuel feeding,
represent a distinct technology and should be treated as a separate category under the NSPS.
Pellet stove manufacturers may only have to make modest changes to their products, possibly
only software adjustments, to meet a standard that should be much more stringent than that of
hand fed, cord wood heaters.
On the basis that the 5G to 5H correction factor will remain in effect. Alternatively, if
EPA decides to discontinue the use of the adjustment factor, the emission standards
must be adjusted downward the equivalent amount.
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Single Burn Rate Stoves
These devices are currently exempt as a result of a high air-to-fuel ratio and/or high
burn rate intended to exclude fireplaces from the original NSPS. EPA estimates that 40,000
of these inexpensive units (relative to certified room heaters) are sold annually. They possess
neither catalytic combustors, nor advanced secondary combustion as do certified units.
Because the air supply to the combustion chamber cannot be shut down like an airtight room
heater, these appliances have not been subject to emissions standards, but they should be.
They are fueled using cord wood and used for the same purpose; space heating and for these
reasons, their air emissions should be regulated in a similar manner.
Like some pellet stoves as noted above, single burn rates stoves are at a competitive
advantage relative to certified units. As a matter of equity to manufacturers who have spent
significant time and resources developing cleaner burning appliances, EPA should regulate
these devices in the same way as other wood burning room heaters.
EPA has proposed to set emission limits for these devices at the same level as the
residential wood heaters, but require testing at only one burn rate. EPA has not presented any
data to characterize the emissions of the currently available single burn rate stoves. We
recommend that EPA treat single burn-rate stoves as room heaters, and establish emission
limits at the same level as room heaters. However, it is essential that EPA subject these units
to the same emission testing and certification requirements as those applied to other room
In particular, the NSPS should require that these units be subject to the minimum burn
rate testing. The current NSPS requires that appliances that cannot achieve this minimum
burn rate be emission tested with a flue damper in place. It was recognized at the time the
original NSPS was developed, and the same concern must be recognized today, that
inexpensive flue dampers are readily available and can easily be installed to force these
appliances to burn at low burn rates, resulting in much higher emissions. Without this testing
requirement, there is no incentive for manufacturers of single burn rate stoves to incorporate
readily available emission control technology.
Implementation Schedule
The 1988 Residential Wood Heater NSPS phased in emission limits on manufacturers,
with a more stringent emission limit two years after the first limit. Likewise, retail restrictions
were phased in over a two-year period to allow manufacturers time to clear out non-compliant
units. In its proposal, EPA is calling for a two-step standard setting process, with a more
stringent standard to apply at the second step and is asking for comment on an extended threestep process. As noted above, we believe these standards should be put in place as
expeditiously as practicable. It is appropriate for EPA to consider the state and use of the
technology, the ability for manufacturers to meet the compliance limits, and provide a limited
amount of time to clear out the retail supply of noncompliant units.
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At present, there is confusion among consumers at the retail level and among air
quality agencies as to the status of some appliances. Manufacturers upgrade existing models
with cleaning burning ones and it may not be possible to easily tell at the retail level, or once
installed, what the certified emissions are. This is an issue with both labeling and product
changes without respective changes to the model name that makes it difficult to differentiate
products. At a minimum, EPA should make changes to the permanent label as discussed
below to correct this source of confusion.
Test Method
We support EPA efforts to improve the repeatability of the certification test methods.
For room heaters, we support EPA’s proposed approach to incorporate tightened parameters
for fuel weight (including coal bed), fuel moisture and limitations on the operation at the start
of the test. We believe that the available data support the inclusion of these more restrictive
test parameters, but EPA should further assess the capability of test labs to control fuel
moisture to the limits in the proposal, and if they are not achievable, promulgate a range that
is achievable.
One of the challenges of the original NSPS was to certify appliances tested at low heat
outputs so that the appliance operates cleanly during overnight burns and when mild
temperatures require lower heat demands. These concerns remain relevant today and we
support the proposed retention of low burn rate testing at the current threshold.
Cord Wood Testing/In-use Challenges
Many factors affect how well a NSPS certified appliance operates in the home and
how much smoke it emits. Differences in fuel species affect emissions. Differences in how
well the wood is seasoned and stored affect the fuel moisture and emissions. Individual flue
installation circumstances as well as the outside temperature and wind speed and direction
affect how well a natural drafting cord wood heater functions.
Very importantly, how the appliance is operated and maintained affects emissions; as
when a non-catalytic stove is operated at a low heat output in which secondary combustion
technology designed into the stove is not functioning to burn the smoke; or when a catalyst
equipped stove is operated with an ineffective catalyst that needs to be replaced.
To address poorly performing or maintained NSPS certified appliances, we
recommend that EPA establish in-use visible emission limits for them. What is needed is a
practical method, with reasonable limits on the amount of time visible emissions are allowed
to account for conditions like appliance start-up and re-fueling for hand fed cord wood
burning devices. Method 22 is the most appropriate in-use compliance technique for this
Since the behaviors of stove operators are so essential to the emission performance of
room heaters, EPA needs to examine potential ways in which emission increases from these
practices can be mitigated in the NSPS, including modifications to the certification test
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method to more accurately characterize the emissions performance of the appliance, as used
in the home.
We recognize that homeowner installation and operation is highly variable and that it
is not possible for a standardized test method to capture the wide range of circumstances
encountered in communities across the country. We are concerned that the laboratory
certification test method may not be representative of emission performance in homes and
applaud EPA efforts to design a testing protocol that ultimately results in clean burning in-use
EPA should examine other laboratory testing approaches that more accurately reflect
in-use operation and fueling, and strive to develop methods that are reproducible.
Reproducible test methods are essential to ensuring confidence in the certification results and
a level playing field for the regulated community.
EPA has proposed to substitute the current ‘crib’ fuel method with a new, as yet
undefined, method that uses ‘cord wood’ to fuel the appliances, along with other changes to
the test protocol. These are proposed to take effect, and become the basis for emission
standard compliance in ‘Step 2’, or around 2020. We agree EPA should move towards a cord
wood test method and it is critical EPA build upon the small but limited database that exists
for cord wood test data. As EPA gathers and evaluates this important cord wood test data, we
encourage EPA to establish a more stringent Step 2 emission level based on crib wood test
and once sufficient cord wood test data becomes available, apply a conversion factor for an
equivalent cord wood emission level.
Hydronic Heaters
Like the process proposed for room heaters, EPA is proposing a two-step process of
standard setting with the first step being equivalent to that in the current voluntary program
and a more stringent standard to apply in the second step.
Emissions regulations of hydronic heaters are long overdue. In 2007, the trade group
representing hydronic heaters asked EPA to regulate them through a revision to the NSPS as
EPA is now proposing. These devices are known to produce extremely high emissions of fine
particulate, carbon monoxide and toxic pollution, particularly during start-up and heat demand
stand-by. In some jurisdictions, they have become the chief public air pollution complaint.
Recognizing the need to improve the emissions performance of these devices, EPA
and the northeast states developed a federal voluntary program that ultimately led to state
adopted regulations. It is a clear instance in which air quality regulations created an incentive
for companies to make technological improvements. This effort has demonstrated, not only
that hydronic heaters can be made cleaner, but has produced in an adequate emissions data
base on which to set achievable emission limits.
We support the ‘Step 1’ standard EPA has proposed (0.32 lb/MMBtu, the current
voluntary standard level), and a more stringent ‘Step 2’ standard. We believe that, like the
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emission standards for room heaters, EPA should proceed as expeditiously as possible. This
is particularly important in the short term, since cleaner burning technology is already widely
available in the market, but only required in a few areas of the country. We are concerned
about EPA’s proposed hydronic heater test method and recommend EPA seriously consider
some modifications to improve it. EPA should require a density range for the test wood used
in the method; currently oak (hardwood) is required. In the Northwest, softwoods are more
commonly used in wood fired appliances and test results by EPA and the State of Washington
exhibit particulate levels (using softwood) more than three times higher than hardwood fuels.
Additional method changes should also include an emissions cap (g/hr) to reduce the
emissions from oversized units operating below their optimum range and to capture emission
spikes from cycling units.
As noted above, we believe EPA should also establish in-use visible emission limits
for all NSPS certified appliances, including hydronic heaters. To reduce the cycling
frequency and associated emission spikes, we also believe EPA should implement effective
regulatory and non-regulatory approaches with the goal of ensuring that hydronic heaters are
sized appropriately for the heat load.
As noted above, the permanent label lacks specificity about the certification status of
the appliance. This can be problematic during stove change-out programs, or in places like
Oregon, where uncertified unit must be removed upon the sale of the home. Confusion over
appliances with overlapping compliance status should be corrected in the future through more
specific information on the permanent label. We also support the proposed requirement to
make the permanent label more visible, so that for instance, fireplace inserts don’t have to be
pulled out of their enclosure to verify their certification status.
EPA proposes to do away with the temporary labels, or ‘hang tags.’ We think there
are good reasons to retain the temporary labels, if the information on them represents actual
emissions, efficiency and heat output range produced on a comparable basis during emissions
certification testing. While this information can be made available without labeling
appliances, its availability at the point-of-sale will make it easier for consumers to select the
cleanest burning, most efficient heater that is appropriately sized for their heat load.
Finally, these revisions proposed to the NSPS will require significant resources on the
part of EPA to implement. EPA must demonstrate its commitment to implement this more
complicated regulatory program covering a broader range of appliances and a host of test
methods that have not previously been used for regulatory purposes. It can do so for example,
by establishing an effective oversight program that has been missing from the random
compliance audit program and an electronic means of sharing compliance testing information
with interested states.
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Thank you for the opportunity to comment on the proposed Standards of Performance
for New Residential Wood Heaters, New Residential Hydronic Heaters and Forced-Air
Furnaces, and New Residential Masonry Heaters. If you have any questions about our
comments or require further clarification, please contact me at 206.254.9145.
Dan Johnson, Executive Director
WESTAR Council
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