Demand for automation in wood stoves moves forward in Europe, but could be sidelined in the U.S.

Updated July 18 - The newest type of stove on the market is the automated or ‘smart’ stove that use sensors and computer chips to adjust airflow, instead of relying on the operator. Automated stoves enable the operator to "load and leave," allowing the stove to maximize efficiency and emissions reductions on its own. These stoves are likely to be the next major step towards cleaner residential wood heating because it is well-known that poor operation by the consumer is one of the main reasons for excessive smoke, and often it is the main reason. 

Automation does not just seek to address poor operation by the consumer.  It also can assess variable draft conditions caused by different chimney configuration, the altitude of the home, and the moisture content of the wood.  In addition, automated stoves are often interactive, helping to educate operators through visual prompts or detailed apps on smart phones. 

 

In Europe, automated stoves have been advancing far more quickly and are recognized as by the regulatory community as an important solution.  In the U.S., the EPA and other agencies are focusing on an equally important process - improving test methods for manually operated stoves – with little attention to automation. Improved test methods still leave manually operated stove vulnerable to wildly variable real-world emissions.  

 

Outside of regulatory circles, automated stove technologies have been promoted in the U.S. by the Wood Stove Design Challenge, a series of technology competitions, and by funding from the US Department of Energy in association with national labs.  A 2023 study from Brookhaven National Lab described the technology as “a minimal set of measurement sensors and a heuristic control strategy to actively modulate incoming air to enhance stove combustion performance, thereby eliminating user-error as a factor for emissions production.” More recently, researchers at Oregon State University and Aprovecho Research Center are focusing on automated technologies that show PM reductions up to 95% compared to older models

 

The first such stove on the US market, MF Fire’s Catalyst, launched in 2016, is now off the market. The second, Charnwood, a British manufacturer entered the US market in 2020 with their Skye E2700. The company say, “This stove uses Charnwood I-Blu combustion intelligence that continuously monitors the state of the fire and optimizes efficiency while reducing emissions through real-time adjustments. Air is introduced in just the right amounts, in the right places, at exactly the right time to ensure a cleaner, highly efficient burn.”

 

A third manufacturer, Pacific Energy has added automated technology to three of their stove models. The Neo 1.6 LE2 and the larger NEO 2.5 LE2, both of which come in freestanding and insert models. Under their True North brand, the TN25 C, they use the same technology on a hybrid stove with a catalyst that is continuously engaged, and does not have a damper control. According to an email from Pacific Energy, they use an “algorithm controlling two sources of supplemental air, working in the background to seamlessly improve combustion.  This patent pending technology uses two probes to monitor the firebox and the flue temperatures. Based on the absolute, delta and the rate of change in temperatures, the combustion is being optimized at all times.”  Pacific Energy markets these stoves as regular wood stoves without explaining the details of their automation to the consumer. 

 

The Canadian manufacturer SBI won an award at the 4th Wood Stove Design Challenge for their progress toward an automated stove and they received a grant from the DOE to develop it. A final version of it is expected to be EPA certified and on the North American market later in 2025. 
 
Automated stoves on the European market
In Europe there has been far more R&D and diversity of automated stove technology.  Notably, in Europe, manufacturers highlight the environmental benefits of automation to the public and to the regulatory community. Models include: 

 

Hase, Lima IQ (Germany)

Hwam SmartControl (Denmark)

Nordica, Larissa (France)

Rika, Rikatronic4 (Austria)

Scan Zensoric Technology,  (Denmark)

Xeoos Twinfire Blue (Germany)

Wodtke, Stage F (Germany)

Full vs. partial automation.  There are many ways to automate a wood stove and one of the main variables is whether the stove still has air levers that the operator can control.  If the stove has controls for the operator, it is virtually impossible to tell if the automation can override the operator, or vice versa.  Many consumers, particularly in North America, want to at least have the sense that they can control air flow, which is key to heat output.  Otherwise, control of heat output can be with the amount and frequency of wood that is loaded into the stove. Also, there is always the question of whether and how well an automated stove works during a power outage.  Most, if not all, can work, but will do so sub-optimally. 

Bi-metal springs that have been used for decades in stoves produce a very modest amount of automation to stoves, and they can be used in conjunction with electronic automation strategies.  

Other features. Some stoves have a LED light that will come on when its time to reload the stove.  Some are connected via wi-fi apps and can produce a sound to prompt the consumer when to reload. The Austrian company Rika has a feature where you load firestarter in the tray, add wood, and then you can program the stove to start remotely, as pellet stoves can.

Aftermarket solutions. Several companies have built devices that can monitor and/or control the airflow of existing stoves or be integrated into new stoves.  Maxitrol is a leading supplier and makes the battery powered “E-Flame air control system” that drives an actuator to control primary and secondary air flow.  It was designed in part to help companies meet future European EcoDesign Directives.  The Danish stove manufacturer Aduro has had it’s Smart Response on the market for several years. The app-connected thermometer provides feedback to the consumer on their smart phone about whether their stove is burning well, and how to improve its use.  Baltimore-based MF Fire is working on something similar. These technologies do not automate stove functions but monitor conditions and prompt the user to give the stove more air, add wood, clean their chimney, etc. 

Regulations and incentives to automate: In the United States, there is little regulatory pressure or incentives for manufacturers to automate.  The new Integrated Duty Cycle (IDC) test protocols are designed so that all types of stoves can be tested and to our knowledge the test method was not designed so that automated features would help a stove pass, though it is possible that will be the case. It is imperative that the National Residential Heating Task Force test the automated stoves on the market in the U.S. and give them the profile that other stove types are getting.  Currently, the test regimen may show the benefits of catalytic and hybrid stoves in the lab, without sufficient data or attention to how well cat stoves are used and maintained over their 10 – 20 year lifetime.  Automated stoves may also have maintenance issues over their 10 – 20 year lifespan, and it’s important to start assessing which automation strategies are more robust.

Test protocols are perhaps the best way to encourage manufacturers to innovate.  Protocols can make it harder for manually operated stoves to pass by requiring air adjustments that are likely to produce more smoke, unless sensors in the stove can adjust airflow themselves.  Making certification marginally tougher for non-cats to pass, leading to a growing percent of catalyst and hybrid stoves, is not an ideal solution compared to growing the number of automated stoves on the market.

At the state level, change-out and other incentive programs can start to recognize automated stoves and give them higher incentives.  Massachusetts is the only state that sought to provide incentives to automated stoves in a change out program in 2017 but it came too early and automated models were delayed coming on the marketplace.  States and air agencies can start to make consumers aware of this new type of wood stove, along with catalytic, non-catalytic, hybrid and pellet stoves. 

The lack of attention and support for the development of automated stove technology in the United States is connected to similar lack of support for cleaner pellet heating appliances.  Despite the ability of pellet stoves to emit very low levels of PM, the EPA allows them to emit the same level of PM as wood stoves, even though they have a different type of fuel, which should lead to stricter emission standards. In Europe, the EcoDesign Directive of 2022 requires pellet stoves to emit only half of what wood stoves are.  

The lack of “eco” or “green” labels for wood stoves in the U.S. has left manufacturers with little incentive to produce cleaner or automated stoves.  In Europe, some eco labels require pellet stoves, for example, to produce a quarter of the PM of wood stoves, and half of regular pellet stoves.  Manufacturers selling on the US market have mainly focused on achieving 75% efficiency, in order to qualify for the tax credit under IRS Section 25C.  Congress revoked that section, effective Dec. 31, 2025 and its unclear if it will be a permanent revocation or just for several years.  The credit has often lapsed since 2005, when it first began.  In Europe incentives have steered away from residential log heaters and focused on the best pellet stoves and boilers, which is a possible path forward in the U.S.

In Europe, some manufacturers feel that is not if, but when, they will have to start producing automated stoves. There is more urgency in Europe because of more widespread use of wood stoves in cities like London, and densely populated areas of Denmark, Netherlands, France, Germany and other countries. The German Blue Angel label and more local regulatory efforts, such as in Berlin, have also led to far more innovation and R&D on automation.  As in the U.S., lobbying by industry is slowing efforts at national and local levels to pass stricter measures that could lead to quicker adoption of automated stoves and more reliance on pellet stoves.

In early 2025, the European Commission released draft language of a new directive to take effect in 2027, including language that automation in stoves would be required. This led to strong industry push-back, and work on the new directive has been delayed.  The European Committee of Manufacturers of Domestic Heating and Cooking Appliances stated:

 

“The requirement of for automatic combustion control systems, additional testing, second conformity contradicts Ecodesign principles: it increases costs, energy consumption and maintenance need, limits technological neutrality and makes appliances more expensive.”
 
“Any Ecodesign regulation should not favour specific technologies. It should be technology-neutral and allow manufacturers to choose how to meet the regulation's requirements…. Although not explicitly required, a stove without a built-in catalytic converter and electrostatic precipitator is unlikely to meet the emission requirements. All seven known Blue Angel stoves have these features.”

 

This industry response to the draft of the next European Directive has many valid points which will also be part of the landscape in North America.  Regulators on both continents should shift their focus away from manually operated stoves and address these concerns and others as they move toward next-generation solid fuel heating solutions. One European study found automation reduced PM by 66% compared to one test method.

 

 

More resources on automated stoves

 

Eurocities, “Cities call for stronger EU rules on new wood-burning heaters to tackle deadly air pollution,” June 2025

AGH Webinar, “Harnessing Electronics for Cleaner, Smarter Wood Heating,” June 2025

14th U. S. National Combustion Meeting, “Forced-draft Airflow Control Tuned to Reduce PM Emissions in a Cordwood Room Heater Under Variable Operating Conditions,” 2025

 

Chemical Engineering Reactions. “Reducing Emissions from Current Clean-Burn Wood Stove Technology by Automating the Combustion Air Supply and Improving the End-User Interaction -Two Important Primary Measures,” 2023

 

IEA Bioenergy, “Design of Low Emission Wood Stoves,” 2022

 

Tarm Biomass, “Automated Wood Stoves: Technology Policies and Barriers,” 2017

 

Technical University of Denmark, “Guidelines for automated controls for wood stoves,” 2017

 

AGH Blog, “Automated stoves entering the marketplace,” 2014

 

AGH Blog, “Nine reasons manufacturers don’t use sensors in wood stoves,” 2013

The Alaska wood stove regulations – cleaning the air or a proxy war?

On Sept. 26, the EPA issued a resounding victory to Alaska’s strategy for improving the air in the Fairbanks area, rebuking virtually all of industry’s objections.  That victory came from the approval of Alaska’s State Implement Plan (SIP) to reduce wood smoke PM2.5 in the Fairbanks non-attainment area.

In essence, Alaska proposed different and stricter standards for wood stoves to be sold and installed in Fairbanks.  They will not allow cordwood boilers, coal heaters, stoves that emit more than 2 grams, or stoves that emit more than 4 or 6 grams during any hour of testing, and multiple other restrictions.  All of this helps. HPBA and more than a dozen wood stove manufacturers mounted a major effort to beat back the Alaska regulations, making the case that much of Alaska’s approach was arbitrary and capricious, not based on evidence, contradicted federal standards, etc. etc.  EPA’s ruling took the side of Alaska on every issue, often by simply stating that states have the authority to be more stringent than federal standard, rather than addressing the details of industry’s points.

 

Why this is a big deal

What everyone needs to understand is that the little city of Fairbanks Alaska has become a proxy war in a much larger struggle over the future of wood stove testing.  Much of Alaska’s work to review stove certifications did not address air quality in Fairbanks, but it does have major national ramifications.  Alaska developed its own list of stoves that could be installed in Fairbanks that was not based solely on emissions criteria.  Instead, it was mainly based on whether the certification paperwork was complete, and they could verify that the test labs correctly followed EPA stove testing regulations, despite the existence of some grey areas.  This set-in motion an unheralded level of scrutiny on testing done by all EPA approved labs, and sent the EPA into an embarrassing tail-spin, as they showed that the EPA had abdicated its role in effectively overseeing its certification program.

The Fairbanks North Star Borough 
(FNSB) non-attainment map.

Alaska’s scrutiny of certification paperwork was sometimes clumsy, and they found hundreds of details were missing, requiring manufacturers to show them that they often were there, but just difficult to find.  EPA has never provided a consistent format for labs to report data and it has been difficult to get the EPA to confirm which details needed to be included in the certification reports. But usually the details Alaska could not find were in fact missing and they uncovered serious patterns and deficiencies in many certification reports, something that few in industry are willing to admit. Those deficiencies had been in plain sight for years, but nobody looked carefully enough. The EPA, scrambling to show they take wood stoves seriously, began a slow but steady process to figure out what went wrong and how to fix it.  They commenced their own review of certification paperwork and over a year later, they are now sending letters to manufacturers requiring them to provide missing data.  Moreover, they are taking the unique step of requiring some stoves to be retested, similar to the audit testing that HPBA fought against.

 

The significance of the EPA’s ruling on Alaska’s SIP is difficult to summarize, as it has many highly technical themes, each one difficult to assess on its own merits.  Suffice it say that the stove community is in the midst of a historic period of change that had already started with the 2016 EPA decision to design new stove testing protocols, using the Integrated Duty Cycle (IDC) model developed by NESCAUM. Alaska has now tipped the balance of power toward a wider review of EPA’s certification program – and its enforcement and compliance unit.  One manufacturer went so far to say that Alaska had improperly pre-empted the EPA by creating a “de facto federal standard.”  There is the possibility that other states may follow Alaska’s approach, either through regulations or voluntary programs like change outs.  

 

AGH believes the Alaska initiative has had several positive impacts.  First, it’s made labs test stoves more carefully, and properly dot their i’s and cross their t’s.  Secondly, it forced the EPA to take their wood heater certification program more seriously, run it more professionally and better understand the grey areas that they had unknowingly included in the 2015 stove regulations.  

 

The long term view

But the most important outcome is something that all parties can agree on: understanding how to improve test methods so that they encourage engineers to design stoves that will perform better in the hands of consumers.  This is what we all are working for.  Alaska has now brought attention, if not clarity, to scores of issues that make for an effective certification program.  A good certification program needs clear guidance to manufacturers and labs and it needs a compliance program.

AGH is hopeful that this process will lead to genuinely cleaner stoves that get put through their paces in a test lab just as homeowners will use that stove. It’s useful to consider other EPA certification testing programs and the decades it has taken to understand their weaknesses and reform them, so consumers are getting products that work well in the real world.  

EPA auto emission standards
got stricter - and more realistic.

Automobile testing, for example, went through similar stages.  A revolution in auto testing, in the words of one expert, happened when manufactures were “motivated to produce emission controls that not only pass emission certification testing, but also remain functional when vehicles are in real-world use.”  Admittedly, the auto industry is massive and can afford levels of R&D and compliance that are impossible for the tiny, but resilient wood stove industry. Herein lies the rub: how far can the EPA and manufacturers be pushed to make lasting changes? Both are resource constrained.  Will the EPA stay focused on this program?  If they don’t, will other states undertake their own initiatives?  Will some manufacturers just quit making wood stoves and focus on their carbon intensive but profitable gas appliances? And does their industry association have the leadership and vision to steer industry through this, or will they focus more on legal and regulatory battles that may be difficult to win.  Many of the large stove manufacturers, including the biggest three, have already let their memberships lapse, for a variety of reasons.

AGH believes we need a hearth industry that can produce appliances clean enough to help households get off fossil heating fuels.  We are not there yet, except with pellet stoves and boilers which work well in the hands of consumers and can easily be improved even more.  Most New England states have incentives for pellet heating and western US states should adopt those policies as well. The electrification movement and more extreme and frequent weather events may solidify the demand for wood stoves.  Pellet heating deserves far more incentives.

A set-back for federal change-out funding

The Alaska initiative has also been very problematic and in some ways damaging.  A NESCAUM report made the implausible claim that the EPA cannot assure that new certified stoves are in fact cleaner than old, uncertified ones.  Actual lab and field testing has repeatedly found the opposite to be true.  This report helped scuttle federal legislation sought by HPBA that would have provided tens of millions for change-out programs.  The irony is that much of that funding would have helped lower-income families switch to fuels that produce less PM (but maybe more carbon), like gas, pellets, or electricity (heat pumps).  This occurred during the year that Congress increased the tax credit for high efficiency stoves, which benefits higher income taxpayers.  Change-outs also require professional installation which often reduces future PM, whereas a very large percent of stoves bought with the tax credit are self-installed.

Like America, the stove community has become even more divided, making the process of developing new test protocols more contentious.  It is unclear what individual or entity has the leadership to bring the sides together to hash out the scores of issues in a truly productive way that could reduce the bitter and litigious atmosphere. The Alaska initiative did not help but it could set the stage for more collaboration, if someone can facilitate it.  Up until a few years, 90% of the expertise in stove testing was within industry and the test labs they work closely with to certify their stoves.  This process has changed that dynamic, forcing more people at EPA and state agencies understand the regulations and the science behind stove testing.  

This NYT image shows extremely
slow growth of renewables in our
electric supply, an impediment
to the electrification movement.

There is also little consensus about the future of wood and pellet heating in America.  This process is being driven by air quality agencies who usually don’t take carbon into consideration.  Thus, even if a pellet stove fueled mainly by residuals from sawmills has higher PM than a gas stove, these officials may lean more heavily on the gas scales.  In the US, there is scant leadership that there is in most of Europe promoting certain types of high efficiency wood and pellet heating as part of the renewable energy solution, at least until our grids have a majority of renewable electricity on them.  The EPA – and Alaska – often claim to work under a technology neutral rubric, although neither is technology neutral, nor should they be.  They both need to more aggressively promote cleaner, lower carbon appliances.  The EPA and Alaska even struggle to officially tip the scales more towards pellet appliances, even though their air quality mandate should make that an obvious policy direction. Luckily, while EPA works on how to test stoves, the DOE is funding a complementary process – building innovative, next-generation wood stoves.

Industry has vital expertise that must go into the process of developing new stove testing protocols.  Many individual manufacturers also will be gathering vital test data from internal testing that they could share with the EPA.  NESCAUM is also developing data which they should share at some point. We need thoughtful leadership on both sides to make sure we get genuinely effective test methods that incentivize manufacturers to do the kind of R&D that will lead to stoves that work well in homes.  Industry sometimes seems to think the rule making process should still be a "reg neg" - a negotiated rulemaking that emerged in the 1980s and was used in the first wood heater NSPS.  Reg negs were supposed to reduce the overly adversarial process of traditional rulemaking.  This is not a reg neg but still, effective cooperation and communication can be extremely beneficial.

The lengthy process that led to the 2015 NSPS regulations did not lead to a new generation of cleaner stoves, like the 1988 regulations did.  But we are now asking the right questions and we better understand the nature of beast that we are trying to control.  Who will step forward and reset the relationship between industry and air quality agencies?

EPA's cordwood test protocol for wood stoves moves forward

 AGH wrote to the EPA in June and again in early July, requesting public information about the stove testing that it is undertaking.  We had seen numerous references about the stove testing but could not find more details about it.  Rather than submitting a Freedom of Information request, which would likely provide a jumble of emails and miscellaneous documents, we urged the EPA to provide an overview.  Details about the EPA’s stove testing program are well known by HPBA insiders, and by staff at NESCAUM and NSERDA, yet we have consistently found that the EPA, nor those organizations, share information very well. This blog may be updated soon with rejoinders from experts who take issue with the EPA's narrative.  

This letter from the EPA partially explains how and why the EPA approved an IDC (ALT-140) test method without a full certification test report using that method.  NYSERDA and NESCAUM still have not produced certification level test data for their IDC method "although we [the EPA] understand that Alaska will be providing us with additional data demonstrating use of the ALT-140 for compliance testing."  

In the past 10 years, the EPA has rarely had any budget for lab testing, so its current budget of one million is significant.  AGH believes that its imperative for the EPA to develop its own data and not just rely either on industry or groups like NESCAUM and NYSERDA.  We reproduce below the email verbatim from Stef Johnson, leader of the EPA's Measurement Technology Group.  The photos were added by us.

July 20, 2021

Dear Mr. Ackerly: 

 

Thank you for the questions you forwarded in your July 9, 2021 email.  I appreciate the thoughtfulness of you questions and the opportunity to engage with you on this important topic.  In particular, I’d like to clarify the steps in EPA’s processes for: 

·         New Test Method Development and

·         Alternate Test Methods (ATM) 

 

New Test Method Development 

 

In the method development process, EPA creates new measurement methods for regulatory purposes.  In the case of EPA developing new test methods for wood heaters, EPA has embarked on a public process that engages stakeholders as we develop a new measurement method for this sector.  EPA’s Measurement Technology Group, the group I lead, began the process by convening a Roundtable consisting of manufacturers, Hearth Patio & Barbeque Association (HPBA) staff, state and local regulators, test lab technical staff, and multijurisdictional organization (MJO) representatives.  The Roundtable participants gathered to discuss the use and vetting of the Integrated Duty Cycle (IDC) method for certification of wood fired stoves and consider making that testing approach an EPA test method.   

 

After the January 2020 meeting where we discussed the IDC approach and the ASTM E3053 test approach, the agency determined that we would pursue development of the IDC as an EPA method.  We have been working in that direction ever since.  The process to conduct method precision testing of an IDC for wood heaters, one for hydronic heaters, one for forced-air furnaces, and one for pellet heaters is resource intensive and complex.   

 

EPA remains committed to transparency and open dialogue as we explore and develop new methods for compliance testing of wood heating appliances.  We have provided the Roundtable group information about our Quality Assurance Project Plan (QAPP), the IDC method for wood heaters -- the current subject of our trials, and the Tapered Element Oscillating Microbalance (TEOM) Standard Operating Procedures.  We have also shared supporting spreadsheets for using these methodologies.  We have posted this and other information in a public docket (EPA-HQ-OAR-2016-0130) and we have begun using this posted IDC, along with TEOM measurements in our contracted laboratory.     

 

The EPA is paying for 26 tests at PFS-
TECO testing in Portland, OR.

We are conducting 52 tests (26 paired tests) at a West Coast lab (PFS-TECO) and will be comparing those data to a duplicate effort that will be funded by NYSERDA and conducted at ClearStak laboratories in Connecticut.  Within each lab, we are doing paired testing to look at intra-laboratory variability -- known as repeatability testing.  We will be comparing the inter-lab variability (method reproducibility) between these bi-coastal sets of 26 test pairs.  This helps us understand the test method performance with respect to overall variability and informs our decisions as to the appropriateness of the test method for use with a given emissions standard.  EPA has committed nearly $1,000,000 to the West Coast portion of wood heater test method work, and to a study of TEOM precision to be done at EPA’s facility in Research Triangle Park, NC.  This type of data has never been collected for any wood burning appliance test method to date.   

 

All data we develop from our trials will be publicly available and placed into the same docket as the QAPP and IDC /TEOM methodologies.  We will convene the Roundtable after the wood heater precision testing is complete and we have data to discuss.  Certainly, there will be lessons learned along the way and improvements made.  As you may know, NYSERDA is also conducting wood heater precision testing, and we expect that they will make their data public.  East Coast testing will likely begin in mid-September.  We anticipate that a full data set will be available for discussion by in early 2022.  Again, this is for the development of a wood heater IDC compliance test method.  Finally, we will propose, take public comment, and finalize a new compliance test method.  All of this will be a public process, and all of the data will be available for review.   

NYSERDA is paying for 26 tests of
the same stoves at ClearStak in
Connecticut.  ClearStak offers
transparency in testing by video taping 
the tests but it is not known if these 
tests will be videotaped or if the tapes
will be released to the public.

 

Alternative Test Methods 

 

The Alternate Test Method (ATM) approval process is different than compliance test method development.   In the ATM process, the requestor is responsible for providing sufficient information to the agency to demonstrate that the proposed Alternate Test Method is appropriate for compliance testing purposes.   Requesting an ATM is an option available to any affected party. The proposed ATM must be deemed by the Measurement Technology Group to be appropriate with the final air pollution standard.  The entity requesting the ATM must demonstrate compliance with a Federal subpart regulated by 40 CFR Part 60, such as subparts AAA or QQQQ regulating wood burning residential heating appliances. 

 

EPA’s Measurement Technology Group receives requests for alternate means of compliance testing from affected source categories, from electric utilities to wood heater manufacturers and everything in between.  We are responsible for reviewing each request and make a technical determination about the appropriateness.  We either work in a direct back/forth manner with the requestor or we agree to the request with some stipulations. (You will note we listed several in our 2021 ALT-140 approval letter).  

 

In sum, the ATM approval process is a technical exchange with a requestor followed by a technical evaluation by my staff.  The goal is to approve compliance testing that meets a specific need and is appropriate for the compliance purpose as outlined in the rule.  While such evaluations may involve exchange of data between the requestor and EPA, each request is evaluated and assessed on a case-by-case basis.  

 

In situations where there is not any test method available, for example, EPA will evaluate the request differently than in situations where we have already approved an ATM.  With regard to ALT-140, we have had the opportunity to learn about the IDC development process through multi-party meetings from 2017 to 2020.  The information shared during this time about the IDC illustrated that this method provides a more rigorous test assessment of heater performance and therefore, provides a more conservative compliance demonstration approach.  Such conservative approaches (more difficult to pass the test) are nearly ideal for Alternate Test Method processes because one of our goals with the ATM process is to not relax the standard in any manner.   

 

That said, when EPA received Alaska’s request to approve an alternative test method for demonstrating compliance with the New Source Performance Standard Subpart AAA, Standards for New Residential Wood Heaters in December 2020, we were not aware of data that demonstrated that a wood heater could meet the emissions limit of the rule using the IDC.  Therefore, we asked Alaska to provide us with that information.  While what they provided to EPA is not an entire test report, it is credible enough for us to allow the use of the test method for compliance demonstration, where a compliance test must fully document all of the test method QA/QC details to satisfy EPA’s Office of Enforcement and Compliance Assurance (OECA)’s requirements.   

 

Finally, using an ATM itself is optional and my staff ensures that all alternative methods are equivalent or more stringent than the test method in the EPA regulation.  No one need ask to use one unless they decide that it is in their interest to do so.   In the case of the Alaska request, EPA’s approval of ALT-140 provides a cord wood compliance pathway for manufacturers wishing to sell in the Fairbanks-North Star area.  They are also free to conduct crib fuel tests and sell crib fuel tested units in that area.   

 

Finally, EPA has received 5 spreadsheets from NYSERDA/NESCAUM in support the Alaska ALT-140 request and they are available upon request.  To date, EPA has not received any other NYSERDA/NESCAUM test data used for their IDC method development purposes, although we understand that Alaska will be providing us with additional data demonstrating use of the ALT-140 for compliance testing.  

 

I hope this has been helpful for your understanding.   

 

Very sincerely, 

 

Steffan Johnson

Leader - Measurement Technology Group

US Environmental Protection Agency (EPA)

Related stories

Nine states urge the EPA to revoke the ASTM cordwood method (May 2021)

EPA announces overhaul of wood stove certification process (April 2021)

AGH response to NESCAUM report on wood stoves (March 2021)

EPA and states vigorously defend audits of wood stoves (Sept. 2020)

EPA finds lapses in cordwood certification testing (July 2019)

Nine states urge the EPA to revoke the ASTM cordwood test method

A certification test using ASTM E3053
where logs are loaded north-south on
the bottom and east-west on top.  

The Attorney Generals of nine states sent a letter to Chet Wayland, the EPA’s Director of Air Quality Planning and Standards, urging him to reevaluate the ASTM E3053, and revoke it if the EPA reevaluation confirms the findings in a recent report from the Northeast States for Coordinated Air Use Management (NESCAUM).

The Attorney Generals said “certifications relying on [ASTM 3053] Alternative test methods 125 and 127 suffer from deficiencies that artificially lower emissions during the certification tests and allow too much variability and manufacturer or laboratory manipulation to provide a result sufficient to determine compliance with the Standard.” The letter is reproduced below and can be downloaded here.

 

The NESCAUM report that identified deficiencies in test reports that used ASTM E3053 also found significant deficiencies in test reports of stoves that used Method 5G, the official federal reference method for wood stove emission testing.  That report led to an announcement by the EPA in early April that they were overhauling their process of reviewing certification paperwork, but it did not address NESCAUM’s recommendation that the ASTM method be revoked.

Both the ASTM and IDC cord wood
test methods have been accepted as
"broadly applicable" which means any
manufacturer can use them for 
certification testing.  No stove has yet 
been certified with the IDC method.

At issue is what has become the favored test method by manufacturers and labs.  Eighty-five out of 148 cordwood stoves, nearly 60%, of all wood stoves on the market today used the ASTM test, one indication that the test may be easier than Method 28, the traditional test.  Among the close-knit community of stove manufacturers and test labs, there are few explanations of why labs shifted so quickly to use the ASTM test method.

This controversy, like virtually all others around wood stoves in recent years, have to do with heaters that burn wood, not pellets.  Unfortunately, reports, rejoinders and media coverage rarely make that distinction,  resulting in a loss of confidence in all types of heaters.  Pellet stoves remain fundamentally far cleaner than wood stoves in the hands of consumers and their test methods are far less susceptible to interpretation and manipulation.

 

On June 6, the EPA posted the NYSERDA IDC testing protocol. They say: "We have now docketed the TEOM SOP, and IDC Stove Operating and Fueling protocols, along with their associated spreadsheets (fueling calculator for IDC, data processing for TEOM). These files are static for the duration of our sample collection efforts that have now begun in Portland, OR."  This process too has been exclusionary.  The Alliance for Green Heat requested on multiple occasions to join the Roundtable group made up of scores of industry members, state regulators and EPA personnel, but the EPA declined to allow non-industry stakeholders to be part of this process. 

Industry experts affiliated with the main industry association, the Hearth, Patio and Barbecue Association (HPBA), take pride in what they call an open, transparent and consensus-driven process of developing and approving the ASTM E3053 cordwood test method. Its detractors, led by NESCAUM and the New York State Energy and Development Authority (NYSERDA), say ASTM is a private non-profit that copyrights and sells its standards.  They also contend that even though anyone can join the committee developing an ASTM standard, the process can be dominated by industry, and comments and recommendations can be discarded if the core committee members do not agree with them.  

 

Lisa Rector explains the IDC test when
it was first publicly showcased at a
Wood Stove Design Challenge in 2018.

The Technical Contact for the ASTM E3053 development process and a subsequent revision which is still being worked on, is Robert Ferguson, a long-time industry insider who often is a consultant for HPBA.  Approximately 90% of the experts included in the ASTM 3053 development process consisted of representatives of wood stove manufacturers, HPBA staff and test lab staff.  In addition there were about 10 staff from EPA, NESCAUM, WESTAR and non-profits, including AGH.  HPBA paid for some of the testing during the development process and Mark Champion, who has done most of the Integrated Duty Cycle (IDC) testing also did testing of the ASTM method.  AGH offered comments during the ASTM process and was told that test data to back up suggestions was needed.  Comments from NESCAUM were reportedly disapproved.

NYSERDA has been funding NESCAUM to develop their own cordwood test method, which was recently approved by the EPA as a broadly applicable method, at the request of the State of Alaska.  Industry members say NESCAUM and NYSERDA have a clear conflict of interest and are trying to get rid of the competition so that their cordwood test method can be the only one used by test labs.  Industry is also frustrated with the lack of transparency surrounding the development of the IDC test method and the errors in it that would have been found if other experts could have reviewed it and tested it.  Tom Morrissey, owner of  Woodstock Soapstone found scores of errors in the NESCAUM report and identified many problematic issues with the IDC test method.  Ben Myren, a veteran test lab owner, also found many problems with the process run by NESCAUM and the state of Alaska.

An EPA reevaluation of finding
in the NESCAUM report
should include rejoinders
from manufacturers, such as
whether this fuel was correctly
flagged for debarking

It is not yet known whether the demands of the nine states could lead to the revocation of the certification of 85 stoves that were certified with the ASTM method, or whether the EPA would just not allow it to be used to certify additional stoves.  Most of those 85 stoves will be requesting to have their 5 year certification approval extended for another 5 years.  The EPA may require that those stoves go through emissions testing again after 5 years, an option that they appear to have been considering even before the letter from the Attorney Generals based on deficiencies flagged by the Alaska review process.

The nine Attorney Generals represent the states of New York, Alaska, Maryland, Massachusetts, New Jersey, Oregon, Rhode Island, Vermont and Washington  along with the Puget Sound Clean Air Agency.  Absent from this list are Maine, New Hampshire and Connecticut who are members of NESCAUM and prominently listed at the beginning of the NESCAUM report.

Copy of letter:

Attorneys General of New York, Alaska, Maryland, Massachusetts, New Jersey, Oregon, Rhode Island, Vermont, Washington and the Puget Sound Clean Air Agency

May 21, 2021

Chet Wayland
Director, Air Quality Assessment Division
US EPA Office of Air Quality Planning and Standards, 109 T.W. Alexander Drive, Mail Drop E-143-02 Research Triangle Park, NC 22710

Re: Request that EPA Revoke Use of Alternative Test Methods 125 and 127 for New Source Performance Standard Wood Heaters Certification

Dear Chet Wayland,

On behalf of the Attorneys General of New York, Alaska, Maryland, Massachusetts, New Jersey, Oregon, Rhode Island, Vermont, Washington and the Puget Sound Clean Air Agency, we write to request that EPA revoke alternative test methods 125 and 127, both based on ASTM 3053, to certify compliance with the New Source Performance Standard (the Standard) for wood heaters. These alternative test methods threaten to undermine the air quality benefits of the Standard.

As outlined in an April 28, 2021 letter from multiple state regulators to EPA, the Alaska Department of Environmental Conservation, New York State Energy Research and Development Authority, and Northeast States for Coordinated Air Use Management have together undertaken a comprehensive review and audit of wood heaters certified under test methods relying on ASTM 3053. These entities found that certifications relying on those alternative test methods suffer from deficiencies that artificially lower emissions during the certification tests. Alternative test methods 125 and 127 allow too much variability and manufacturer or laboratory manipulation to provide a result sufficient to determine compliance with the Standard. In light of these findings, we request that EPA reevaluate the authorizations for alternative test methods 125 and 127, and if EPA corroborates the reports’ findings, revoke these alternative test methods. See 40 CFR §§ 60.8(b), 60.534(a)(1)(ii) (specifying authority to authorize alternative test methods); see also 40 CFR § 60.533(l)(1) (allowing revocation of certifications for wood heater models where test results cannot be replicated).

States continue to invest considerable resources to facilitate the exchange of older, more- polluting wood heaters for newer less-polluting units. Wood heater certifications based on deficient test methods, which produce artificially lower emissions than what can be achieved by homeowners, undermines these efforts. Furthermore, wood heaters with high particulate matter emissions pose dangers to the health of our residents, including vulnerable populations, such as children, the elderly, and environmental justice communities. EPA can mitigate these problems by requiring the use of either EPA’s method 28R or alternative test method 140 (the Integrated Duty Cycle Test Method that EPA has indicated represents the future of certification test methods for wood heaters).

Last year, numerous States submitted an amicus brief supporting EPA’s authority to conduct auditing of wood heater certifications. See States’ Amicus Brief, Hearth Patio & Barbecue Ass’n v. U.S. Envtl. Prot. Agency, No. 15-1056 (D.C. Cir. Sept. 21, 2020), ECF No. 1862523. In that amicus brief, we argued that manufacturers could effectively evade the Standard, and thus contribute to harmful air pollution, by using alternative test methods based on ASTM 3053 for test certifications and running tests more loosely than permitted by method 28R. For example, these methods do not require the use of fuel logs that are 5/6 the length of the firebox, and using shorter logs allows for cleaner burns. What is more, gaming the tests leads to results that cannot be replicated.

We now ask that EPA take the additional step of reviewing the reports and information brought forward by air regulators and other parties and to reassess using alternative test methods 125 and 127. If EPA findings corroborate the state air regulator’s reports—including that stoves certified under alternative test methods 125 and 127 do not reliably produce emissions below the Standard—then EPA should disallow the use of these methods. Moreover, when the certifications for wood heater models that used alternative test method 125 or 127 are up for renewal, EPA should require recertification testing using method 28R or alternative test method 140. See 40 CFR § 60.533(h)(2) (indicating certifications expire every five years).

Thank you for your attention to addressing this troubling threat to the air quality protections afforded by the Standard.

Sincerely,

FOR THE STATE OF NEW YORK

LETITIA JAMES
Attorney General of the State of New York

By: /s/ Nicholas C. Buttino NICHOLAS C. BUTTINO MICHAEL J. MYERS
Assistant Attorneys General Environmental Protection Bureau The Capitol

Albany, NY 12224
Tel: (518) 776-2406 nicholas.buttino@ag.ny.gov

FOR THE STATE OF ALASKA

TREG R. TAYLOR Attorney General

By: /s/ Steve E. Mulder
STEVE E. MULDER
Chief Assistant Attorney General 1031 West Fourth Avenue, Suite 200 Anchorage, AK 99501
Tel: (907) 269-5100
Fax: (907) 276-3697 steve.mulder@alaska.gov

FOR THE STATE OF MARYLAND

BRIAN E. FROSH
Attorney General of Maryland

By: /s/ Michael Strande MICHAEL STRANDE Assistant Attorney General Department of the Environment 200 Saint Paul Place

Baltimore, MD 21202
Tel: (410) 576-6300 michael.strande@maryland.gov

FOR THE COMMONWEALTH OF MASSACHUSETTS

MAURA HEALEY
Attorney General of Massachusetts

By: /s/ Carol Iancu
CAROL IANCU
TURNER SMITH, Deputy Chief Assistant Attorneys General Office of the Attorney General Environmental Protection Division One Ashburton Place, 18th Floor Boston, MA 02108
Tel: (617) 963-2428 carol.iancu@state.ma.us

FOR THE STATE OF NEW JERSEY

GURBIR S. GREWAL Attorney General

By: /s/ Lisa J. Morelli LISA J. MORELLI
Deputy Attorney General New Jersey Division of Law 25 Market Street

Trenton, NJ 08625
Tel: (609) 376-2745 Lisa.Morelli@law.njoag.gov

FOR THE STATE OF OREGON

ELLEN F. ROSENBLUM Attorney General

By: /s/ Paul Garrahan
PAUL GARRAHAN Attorney-in-Charge
STEVE NOVICK
Special Assistant Attorney General Natural Resources Section

Oregon Department of Justice 1162 Court Street NE
Salem, OR 97301-4096
Tel: (503) 947-4593 Paul.Garrahan@doj.state.or.us Steve.Novick@doj.state.or.us

FOR THE STATE OF RHODE ISLAND

PETER F. NERONHA
Attorney General of Rhode Island

By: /s/ Alison B. Hoffman
ALISON B. HOFFMAN
Special Assistant Attorney General
Rhode Island Office of the Attorney General 150 South Main Street
Providence, RI 02903
Tel: (401) 274-4400 ext. 2116 ahoffman@riag.ri.gov

FOR THE STATE OF VERMONT

THOMAS J. DONOVAN, JR. Attorney General

By: /s/ Nicholas F. Persampieri NICHOLAS F. PERSAMPIERI Assistant Attorney General Office of the Attorney General 109 State Street

Montpelier, VT 05609
Tel: (802) 828-6902 nick.persampieri@vermont.gov

FOR THE STATE OF WASHINGTON

ROBERT W. FERGUSON Attorney General

By: /s/ Caroline E. Cress CAROLINE E. CRESS Assistant Attorney General Office of the Attorney General P.O. Box 40117

Olympia, WA 98504-0117 Tel: (360) 586-4613 caroline.cress@atg.wa.gov

FOR THE PUGET SOUND CLEAN AIR AGENCY

By: /s/ Jennifer A. Dold JENNIFER A. DOLD
General Counsel
Puget Sound Clean Air Agency 1904 Third Avenue, Suite 105 Seattle, WA 98101

Tel: (206) 689-4015

jenniferd@pscleanair.gov