Thursday, October 24, 2019

Pellet stove performance makes big gains as interest in renewable energy grows

In 2009, the average pellet stove emitted 2 grams of smoke (particulate matter) per hour. No one had any idea which stoves were efficient and which weren’t.  Ten years later, the average pellet stove certified to be sold as of May 2020 emits only 1 gram per hour.  By cutting that number in half, the emissions around homes that heat with these new pellet stoves are barely perceptible.  

Efficiency has also risen, with the average efficiency of pellet stoves now nearly 74%, but some as high as 85%, based on the EPA's certified stove database.  Ten years ago, average efficiencies were under 70%. 

A variety of factors led to these performance improvements but it’s not yet clear if they will lead to an uptick in installations.  Based on interviews with numerous pellet stove retailers, most consumers don’t buy pellet stoves based on increased performance values. 

“We see a lot more customers who want a renewable heat source and are not so concerned whether it’s going to save them money or not,” says James Cusano, a veteran stove retailer from Concord New Hampshire.  “Consumers are looking for ease of use – which means big hoppers, minimal maintenance and thermostat controls – and many now want to avoid fossil fuels.”

Cusano says heating preferences in New Hampshire are changing and consumers have more options today than they did 10 or 20 years ago.  Heat pumps are an option, but with cold New England winters, stoves are still prized.  For pellet stoves, consumers “want it to be as close as possible to heating with a modern central system, but with a biomass fuel source, and without the much larger investment required for a pellet-based central heating system.”

Other retailers, such as Richard Thomas, who runs Courtland Hardware in Maryland, say renewable energy is not a big driver.  He says many people buying pellet stoves used to have a wood stove and are looking for the ease of use that pellet stoves offer.  Maryland has a stove incentive program driving consumers toward cleaner and more efficient pellet stoves, rather than basic wood stoves.  Massachusetts and New York have similar programs that require turning in an old wood stove.  These states show that harnessing interest in stoves and moving towards pellet heating can be a key strategy for decarbonizing heating fuel loads. 

The renewable energy movement so far is benefiting heat pumps far more than pellet stoves, though both offer the potential for low carbon space heating. Until there is a lot more renewable electricity on state grids, advocates say pellet heat should be an obvious choice, helping to avoid winter electric peak demands that are more likely to be met with combined cycle gas plants than with renewables.

National pellet stove trends

Pellet stoves are well-known in the wood heating community, but many consumers and renewable energy experts still don’t know exactly what they are and how they differ from wood stoves.  No precise figure exists about the number of pellet stoves in use today, but most experts think it is more than 1 million.

Current sales figures are not public but past figures show large swings between years amidst a long term growth pattern.  Pellet stoves have never outsold wood stoves, but they have come close, selling up to 150,000 units some years.  More recently, pellet stoves may be only a quarter or third of wood stove sales (in the 50,000 per year range). Even at 50,000 units a year, however, pellet stoves are being installed at a scale that merits more attention.

There is evidence that pellet stoves are gaining traction, partly from demand of people who used to heat with wood and partly from first time buyers.  In Vermont, one of the few states that includes pellet stoves in surveys on home heating devices, more than 8% of homes use pellet stoves or boilers as their primary heat and an additional 3.6% use pellets as a secondary heat source.    This is a rapid rise from 2008 when less than 2% of homes used pellets as a primary fuel.

Source: Vermont Residential Fuel Assessment, 2014 - 2015

Maryland does not track pellet stove installations but the state released data showing that 85% of people receiving rebates for an efficient stove chose the pellet stove rebate over the wood stove rebate.  Richard Thomas sells pellet and wood stoves at three locations in Maryland in northeast Maryland and he says that 90% of the stoves he sells are pellet and less than 10% are wood stoves.  

The best pellet stoves consistently emit well under 1 gram of PM per hour, 1/5th or 1/10th the emissions of a  wood stove in the hands of the average consumer who may rarely get the results achieved in the test lab.  Like many modern combustion engines – from cars to furnaces – modern pellet stove emissions are almost always invisible and undetectable by the nose, but pellet heaters  still emit more per hour than a car and much more than a modern gas or oil furnace. Bigger PM reductions are still underway with pellet combustion technology and one pellet stove model was recently tested at 0.22 grams an hour, a level that some thought was nearly impossible.  

One stumbling block for pellet stoves is the public perception that they accelerate deforestation.  There are large volumes of sawdust and scrap wood from lumber yards that have been used to make heating pellets in the northeast for decades.  Those volumes can rise or shrink depending on the strength of the housing market and the economy overall.  There was little confusion about the source of fiber for pellets until large corporations started harvesting whole trees from the southern US to ship to Europe to make electricity.  It is now commonplace for people to think that’s how heating pellets are made.  Likewise, many don’t distinguish between small scale heating at 75% efficiency and industrial scale electricity production at 25% efficiency.

The large percentage of pellet stoves sold today is great news for air quality agencies since they operate far cleaner in homes than wood stoves. It’s also great news for the renewable energy community since a pellet stove can run 24/7 and is usually a home’s primary heat source. A pellet stove used as a primary heater in most parts of the US will typically make as much energy as a 5kW residential solar panel installation.


Accurate price data is not available to track changes between 2009 and 2019.  At the high end, top brands sell for $3,000 - $4,000 and installation can add $500 - $750 or more.  At the low end, there is still an abundance of very affordable pellet stoves.  At least seven manufacturers make pellet stoves that sell for $1,000 or less (two of them appear to be on the market illegally and are not EPA certified.) 

A top value stove, the PelPro, has several models that sell for about $1,200 and are among the cleanest and most efficient on the market.  Scott Williamson, a professional pellet stove repair technician from Massachusetts, says with their large hoppers and solid reliability history, it’s hard to find a better pellet stove for anywhere near that price point.  PelPro stoves are sold by big box stores, requiring consumers to find and hire a professional installer and repair technicians on their own, compared to specialty hearth dealers who provide those services and rely on the additional income streams.

The number of certified pellet stove models nearly tripled from 56 in 2009 to 156 in 2019.  Most pellet stove models in 2009 were not yet certified, due to a perceived exemption which was only supposed to apply to stoves that had an excess of 35 parts air to 1 part fuel.

Data shows that cleaner stoves are more efficient stoves

In addition to becoming cleaner and more efficient, there is now a clearer relationship between cleanliness and efficiency.  About half of the sixty-two 2020 certified pellet stoves are below 1 gram an hour, and half are between 1 and 2 grams.  The stoves under 1 gram had an average efficiency of 75.9% and those above 1 gram had an average efficiency of 71.7%: a nearly 10% difference.  This provides an additional motivation for consumers to look more closely at the cleanest stoves, as they also tend to be the ones that will use the least fuel for the same heating output.  

Source: EPA Wood Stove Database (room heaters)
James Cusano of the Stove Barn in New Hampshire also found that “the lower particulate emissions seem to require slightly less of the intensive cleaning that the higher emission models do, and that is critical to the long-term efficiency and reliability of any pellet burning appliance.”

In addition, there is a clear correlation between PM and carbon monoxide (CO).  Stoves emitting less than 1 gram of PM had an average of 0.18 pounds of CO per hour.  Stoves with more than 1 gram of PM per minute emitted an average of 0.29, 38% more.  CO is one indication of good combustion and is expected to correlate with PM.

The road to better performing pellet stoves

The year 2015 marked the biggest turning point for pellet stoves because the EPA required all pellet stoves to be certified and report the results of efficiency tests.  Stove retailer James Cusano says he has seen bigger changes in the bottom of the market than at the top.  Going forward, “the middle and top market models will continue to improve their automations, while the bottom will focus on continuing to try to meet the new minimum expectations at budget price points,” Cusano said.

The EPA decided to set the same PM regulatory levels for wood and pellet stoves, giving pellet stoves a very easy target.  The average pellet stove certified to the 2020 standard of 2 grams an hour emits about 1 gram an hour.  The federal IRS tax credit has also used a single efficiency number for both wood and pellet stoves, which would make far more pellet stove models eligible for a tax credit, if it were to be re-enacted.  Bills in the House and Senate supported by AGH, HPBA and scores of other groups propose a tax credit with a 75% efficiency limit as of 2020 would make most pellet, catalytic and hybrid stoves eligible and most non-cat wood stoves ineligible. 

Innovation and competition have also played an important role in the trend toward cleaner and more efficient pellet stoves.  A half a dozen models now emit less than a half a gram of PM per hour and a dozen are over 80% efficient.  

The US Energy Information Agency releases annual forecasts of heating fuels each fall but do not separate pellet from wood heating.  This year they predict a slight national decline in primary wood heating to a little less than 2% of US households (about 2 million homes), down from 2.2% about 5 years ago.  However, about 8% of American homes use wood or pellets as a secondary heat source, according to the EIA’s recent Winter Fuel Outlook.

Per capita use of wood and pellets as a primary residential heating fuel.  Two states – Vermont and Maine – are in the 10% - 25% category, sharply reducing fossil heating fuel demand in that region.  Source: EIA 2019 Winter Fuel Outlook

Continued improvements in pellet stove performance will help the technology serve a core population of people who currently heat with expensive oil, propane or electric resistance heaters, as well as those looking for renewable options.  And, it may not be long before pellet stoves are designed and tested at or below 0.1 gram an hour, a technological milestone that could coincide with state and national policies aimed at increasing renewable heating goals.

Friday, October 18, 2019

EPA urges manufacturers to stick to May 2020 compliance deadline; says its working towards a cordwood test method rulemaking

On October 15 the EPA provided an update on its wood heater website page urging “affected entities to continue efforts to certify compliance with the NSPS in light of the upcoming May 15, 2020, compliance date.” According to NSPS legal experts, the EPA sometimes issues such updates to provide more transparency when stakeholders need certainty due to an approaching deadline.  

The update is widely interpreted to mean that there will be no sell-through for whole house heaters or any other significant changes in the regulations issued by the EPA in 2015. However, the details of any changes to the 2015 rules will come later this fall when the EPA issues the Final Rule.  

The news was welcomed by the Alliance for Green Heat and many stakeholders, including manufacturers and importers of wood heaters who have invested in R&D and retesting of their heaters that comply with May 2020 emission standards.   Nearly 200 models of wood and pellet heaters are certified to the 2020 standards and virtually all stove companies say they will be ready for May 2020.  Some include innovative designs that achieved emission levels that are six times cleaner than the maximum allowed in 2020.

The sectors of the wood heater industry that most needed a sell-through are the outdoor wood boiler and indoor forced-air furnace makers, both of whom are represented by the trade group Hearth, Patio and Barbecue Association (HPBA).  HPBA’s strategy of seeking relief from Congress and the Administration appear to have fallen through, leaving its litigation against the EPA as the most viable channel for relief.  But that relief will likely not occur before May 2020.

Test methods
A Canadian company who never
had an EPA certified heater
saw a new market open up
for their AirBilo Furnace.
Much of the EPA’s update addressed test methods, and the EPA noted that a newly approved broadly applicable alternative test method for furnaces “may facilitate the ability of manufacturers” of furnaces to comply by May 2020.  This is not the type of relief sought by HPBA, and it’s not yet known if many other furnaces will use this test method for certification.  However the EPA puts it in the context of providing some relief.  It was given to a Canadian company mostly known for maple syrup boilers, but who also makes a very affordable forced air furnace.

The EPA used this update to message that it is already moving on to the next proposed rulemaking, which will be on cordwood test methods.  The update said, “in the coming months, the agency is initiating a series of roundtable discussions with states and other stakeholders to inform the agency’s direction toward a cord wood-based compliance test method.”  In March 2016, the EPA laid out a process for developing improved cordwood test methods. By statute, the next NSPS should be in 2023 but the EPA could issue this rule making earlier.  AGH believes the next NSPS should not focus on reducing allowable PM without first modernizing test methods to ensure heaters are designed for real world use.

Part of the HPBA’s litigation focused on an agency decision to set a 2.5 gram an hour emission standard before setting a test method to meet that standard. Subsequently, an industry led ASTM committee developed the E3053 test method which has become a commonly used method along with the standard crib wood method that has been in use since the late 1980s.   The ASTM method is being widely used now but came under scrutiny by the EPA because of lax reporting by labs using the method.

NESCAUM is developing "Integrated
Dute Cycle" protocols based on the
way stoves are used by consumers.
Since the ASTM method became a “broadly acceptable” alternative test method, NESCAUM has dedicated substantial resources on a broad and ambitious effort to develop a range of new test methods for stoves, boilers and furnaces, as well as for pellet heaters.  The NESCAUM effort is partially funded by NYSERDA and the process and data is not fully public but ultimately it could provide the largest database of cordwood testing ever compiled to develop a North American test method.  Since test methods need to be data driven, this process may give these NESCAUM protocols an entry point and will challenge others to develop or make public data that can lead to a better protocol.

Thursday, October 3, 2019

DOE awards $3 million for R&D to wood stove manufacturers

The MF Fire leadership team in 2018
- Taylor Myers, Paul LaPorte and
Ryan Fisher.
The U.S. Department of Energy (DOE) selected only two companies – MF Fire and ISB Marketing – to receive $3 million for research and development (R&D) through the DOE’s Office of Energy Efficiency and Renewable Energy. The DOE had $5 million for stove and boiler manufacturers but decided to only award $3 million this year.

The two manufacturers are working on next-generation controls and designs for wood stoves that have barely entered the marketplace. Both companies are focusing their efforts on how to make stoves cleaner in the hands of consumers – not just in the test lab – which has become widely recognized as the Achilles heel for the millions of Americans who heat with cord wood.

MF Fire received two grants, one for a device that continuously monitors performance of key combustion indicators and delivers real-time user guidance, and the other for a “swirl stove” that induces and maintains swirling combustion and introduces a new balance of primary, secondary, and dilutive air. ISB Marketing, working with its sister company, Stove Builder International (SBI), is developing a Machine Learning algorithm for a self-regulating wood stove that would have a PM emissions rate below 1.2g/h and offer an overall efficiency of more than 75% (HHV).
The SBI team that produced the award
winning prototype of an affordable,
automated stove

DOE is expected to be able to offer R&D grant funding again in 2020 and may be able to stimulate R&D in more wood heater manufacturers. “We applaud Congressional appropriators and the DOE for funding this R&D that can help millions of Americans affordably heat their homes with next generation wood and pellet stoves,” said John Ackerly, President of the Alliance for Green Heat.

The $2 million for MF Fire is a large cash infusion for a young, small manufacturer with lots of innovative ideas and priority on R&D. “This will enable us to hire new people to ramp up our testing and apply techniques and technologies used by other industries," said Ryan Fisher, COO of Baltimore based MF Fire. “For example, eliminating PM by more thoroughly and aggressively mixing fuel and air has not been done by stove manufacturers. Square, rectangular corners create dead spots that inhibit combustion." Mr. Fisher said. Fisher and his original partner Taylor Myers got their start in designing stoves as graduate students preparing for the first Wood Stove Design Challenge in 2013. The rookies won multiple awards before the age of 25 and still haven’t turned 30. Some see them as the face of a new wave of stove designers.

ISB Marketing, with their SBI counterparts, are taking a similar tack but its potentially applicable on a range of stove models from a major manufacturer. ISB is working with Machine Learning algorithm that will learn how each specific user heats his/her stove. The stove will then adjust its combustion parameters to compensate for any “bad” human behavior that tends to increase particulate matter (PM) emissions and reduce efficiency. A home-designed real-time PM monitoring system will be developed to obtain a better understanding of the stove’s behavior.
Mark Shmorhun, the program
manager at DOE who managed
the grant process, at the 2018
Wood Stove Design Challenge
Marc-Antoine Cantin, President of SBI said in an interview that moving innovative and more risky stove projects through a corporation takes longer, as models that have conventional technology are often green-lighted first. “External R&D funding can help reduce risk,” Cantin said. Even with a million dollars from the DOE, a batch of 26 of the new stoves is not expected to be beta-tested until the winter of 2022-23. SBI won second place at the 2018 Wood Stove Design Challenge for designing a simple, affordable stove that allowed the operator to select high or low heat output and used a low-cost control board and thermocouple sensors to ensure that the stove burned cleanly.

The DOE does not disclose how many applications they received or from whom, but it is widely believed that the agency received few applications for the available $5 million pot of funding. John Crouch, Director of Public Affairs for HPBA, said in an interview, “The funding announcement came at a bad year because manufacturers were scrambling to certify their stoves to the stricter 2020 EPA standards. We hope there will be more applicants if the DOE offers the grants next year.”

The DOE also does not disclose who was on their panel of expert reviewers. According to some companies who applied, some didn’t make it through the process because they had not fully completed the application. Others made it through the first round, and then had to respond to specific questions from the reviewers. Ryan Fisher of MF Fire said he got multiple questions about whether his small company could execute two grants and they had a solid plan in place to manage that. SBI got many questions about their corporate structure. They are owned by US-based Empire Group, who also owns ISB Marketing. They plan to carry out R&D for the grant in the US. Other applicants who made it through the first round, didn't make it through the second round.

The one-page summaries of the 3 grants can be found here: MF Fire-Swirl Stove, MF Fire-Performance Monitoring, ISB Marketing-Automated Stove.

This recent entry of the DOE’s Bioenergy Technologies Department which focuses mainly on biofuels, fills a significant gap for the US government. The EPA provides baseline emission and testing standards and the USDA’s Forest Service provides support for larger commercial use of biomass for heating applications. This marks the first time that a US government agency has provided support for companies to push the boundaries of emission and efficiency controls for residential wood and pellet heaters. The United States has the toughest emission standards for residential heaters in the world, which has kept US companies at the forefront of an industry that can provide affordable, low carbon heating solutions in the switch from fossil fuels to renewables.

The original DOE funding opportunity was directed at stove R&D that included:
  • Novel and innovative residential wood heater designs to improve combustion chamber geometry, combustion air flow distribution, mixing of combustion air with gasification products, stove baffling designs, etc.
  • Improvements in automation of stoves to optimize combustion control.
  • Wood heater power generation via thermoelectric module integration
  • Improvements in catalyst technologies for emissions reduction

Thursday, August 29, 2019

Records reveal successes and challenges in laboratory wood heater testing

Stove and boiler regulations appear to have survived Trump’s first term 

As the wood stove industry nears the May 15, 2020 deadline for meeting stricter emission standards, EPA records show a steady stream of stoves being certified but do not show which models, if any, failed. Manufacturers are required to notify the EPA of stoves they are testing 30 days in advance of the test and to report results after 60 days. Labs are also required to provide emission data to the EPA within 60 days, even if a test is suspended.
Percent of certification tests
scheduled for larger EPA-
approved test labs.  

Data from stove certification tests is a core resource for understanding and improving the effectiveness of regulations. A trove of documents just became available that helps us better understand how stove testing works and how a declining number of EPA staff is trying to oversee detailed regulations that partially rely on an honor system within the industry they are regulating.
Data recently released by EPA shows the pipeline of what is being tested by which lab, what has not been certified and other trends. The 2015 performance standards for residential wood heaters require manufacturers to notify the EPA at least 30 days in advance of the model’s certification test in an EPA-approved laboratory.

The EPA does not maintain a public database of 30-day notices, but the Northeastern interstate air quality organization NESCAUM requested copies of these reports through the Freedom of Information Act (FOIA). The main function of the 30-day notice is to enable the EPA and other agencies to witness testing, which otherwise occurs behind closed doors.

There is nothing proprietary in the 30-day notices and the EPA has no grounds to keep them confidential. Once anyone files a FOIA, the information is made public on the US government FOIA online site. To find the underlying data from these requests, type in “NESCAUM” in the FOIA online site or use these record locators: EPA-HQ-2019-006560, EPA-HQ-2019-000324 and EPA-HQ-2018-006770.

The EPA provided 30-day notices filed between 2015 and 2019 for 143 distinct heaters and 41 duplicate notices.  Matching the 30-day notices to the end result on the EPA's certified heater database indicates that approximately two-thirds of them are certified to 2020 standards.

We could not tell, for example, if crib tested stoves had a higher or lower passage rate then cordwood tested stoves, or which fuel led to more suspensions. The rapid rise in popularity of the cordwood test may indicate the stove manufacturer community’s confidence that they will not be more likely to suspend or fail a test.

More than 10 stoves or central heaters may have been certified since 2015 but only achieved Step 1 standards. The reason for this is unclear. It could be that these stoves already had Step 1 status but failed to achieve Step 2 emission limits. It may also indicate that manufacturers thought the EPA regulations would be struck down or EPA would grant a sell-through, neither of which appear to be happening at this point.

The EPA’s inaction to date on revising  2015 NSPS, and HPBA's strategy to seek repeated delays in their litigation, means that Step 1 stoves will likely be illegal to sell in the US after May 15, 2020. For companies that certified to Step 1 standards since May 2015, the expenses of testing the stove, and potentially modifying it, resulted in a stove that can only be sold for 2 – 4 years on the US market.

Approximately twenty-three stoves with 30-day notices do not appear on the EPA database of certified heaters. It is possible that some of the unlisted stoves have been tested very recently and are still in the certification process, while others might have failed certification testing, did not make it to market for a separate reason, or were discontinued by the manufacturer. 

Test labs

Two labs, Polytest and Omni, certify a majority of stoves for the American market. Polytest is based in Montreal and Omni in Portland, Oregon. PFS acquired Dirigo, so it is now one lab, also based in Portland Oregon. Dirigo used to qualify or certify many outdoor wood boilers. Myren Labs is now only an R&D shop and no longer conducts certification tests, but EPA-approved labs can certify at Myren's lab. Two relatively new European EPA labs – RISE (formally SP) in Sweden and the Danish Technology Institute (DTI) have done a few certification tests.  Only the SZU lab in Czech Republic has apparently not yet done certification testing for any heaters for the US.
Four labs account for the great
majority of certification testing.

Polytest and Omni are also the labs that certify the most stoves with the ASTM cordwood protocol, though all labs now have experience with cordwood for either stoves or boilers.

Many stoves certification tests are done in manufacturers’ or R&D labs by EPA-approved lab technicians who travel there to undertake the testing. Using the same lab that the stove was developed in may be one way to enhance the repeatability of emissions testing and help ensure the stoves passes.

Stoves vs. boilers, crib vs. cordwood

Currently, there are 130 appliances on the EPA's central heater database, however we only have 14 30-day notices in for central heaters (boilers and furnaces), indicating a drastic cut back on testing central heaters to 2020 standards since 2015. Moreover, the testing of those units only resulted in 3 certified heaters: 2 European pellet boilers and 1 domestic cordwood furnace. Possibly the most notable manufacturer that does not have a 2020 certified unit is Central Boiler, who led the charge to stave off the EPA’s 2020 emission standards (litigation still outstanding). Omni labs filed a notice to test a new Central Boiler unit in the winter of 2017, but as this unit does not appear on the EPA list, it is unclear if the testing was suspended or what the results were.

The majority of the 30-day notices obtained were for stoves or room heaters, a category which includes wood, pellet, and multi-fuel stoves. Of these 129 unique room heaters, 36% listed crib wood, 33% pellets, 25% cord wood, and 2% coal/wood and >1% densified logs as the test fuel on the notice. A few 30-day notices did not have a fuel type selected. Twenty-two heaters were listed as having a catalyst, and at least five stoves were single burn rate stoves, a feature that is sometimes not advertised to consumers.

Posting non-confidential lab reports

A new provision of the 2015 EPA stove regulations requires manufacturers to publish their certification testing reports. These lab reports include all emission data, efficiency, grams per hour for each test run and the averaged final numbers. They also include photos of the stove and the crib loads, how the stove was loaded and other data once routinely kept private by manufacturers. These lab reports are usually too technical for the average consumer, but often read by other manufacturers, regulators, retailers and stove hobbyists.

However, these reports are sometimes hard to find on company websites and sometimes appear not to be posted at all by a few smaller manufacturers. After extensive searching, AGH was able to find more than 90% of the 2020 certified heaters’ certification reports online, as well as most Step 1 reports. To be listed as a certified heater by the EPA, manufacturers must provide the EPA with a link to their online report.  While major manufacturers are posting their reports, some remain hidden or difficult to find. And, since most stoves were grandfathered into the 2015 Step emission category, many lab reports detail the original certification testing which happened 15 – 30 years ago. (Once a stove was certified, it received a 5-year certificate of certification, which could be renewed without any additional testing every five years. Some currently certified stoves models are using tests conducting in the early 1990s, having received 5 EPA renewal approvals.)

Lab reports are often more than 200 pages long, but some companies limit what they disclose. Some are only 20 pages, and black out things such as the name of the company representative who witnessed the test. One very old report, from 1992, was only 2 pages long. Manufacturers are only required to post test reports for units tested after 2015, but the overwhelming majority posted test reports for all their certified units, providing testing transparency for the first time and access to third-party efficiency data, which consumers did not have access to before.  A few companies, including Central Boiler, only make reports public for tests done after 2015 and not for all of its certified units. (Those tests reports could likely be obtained through a FOIA request.)

Most companies maintain a single, centralized page for all their lab reports, making it easy to find them with a single click. They are called a variety for names from test report, to EPA data to website report, to certification certificate. Innovative Hearth Products that owns Astria, Ironstrike and Superior have some of the hardest pages to find as they are simply titled “Wood Heaters” and tech support told us that the company did not post those reports. Other manufacturers have the lab test report on the individual product page. At least 4 companies fixed broken links and reposted their test reports after we contacted them, notifying them that we could not locate them.

Links to non-CBI test lab reports

This is not an exhaustive list of manufacturers but includes most of the larger stove companies. (We will periodically update these links.)

Lab reports on central page: 509 Fabrications, Arada Stoves, Astria, Blaze King, Buck Stoves, Central Boiler, DroletEnerzone, Enerco Group (Mr. Heater), England's Stove Works, Enviro, Fire Chief Industries, Foyers Supreme, FPI Regency, Harman, Hearthstone, Iron Strike, JA Roby, Kuma, Morso, Napoleon, Osburn, Pacific Energy, Quadrafire, Regency, STUV, Superior, Travis/Lopi, US Stove, Vermont Castings, Woodstock Soapstone.

Lab reports on individual product pages: Froling, Jotul, MF Fire, RSF, Sierra Products, Thelin, Thermorossi, Timberwolf, Wittus (links go to a sample report).

Lab reports not found: Invicta, Laminox (we sent multiple emails and will post links if we get responses.)

Suspension of certification tests

From a review of 30-day notices of lab tests, and resulting certification, it would appear that virtually no stove fails a certification test. That is because if initial test runs are not going well, the certification test is suspended. There is no point continuing costly tests if the average grams per hour for all the tests is not going to be below 2 or 2.5 grams an hour. However, the EPA’s 2015 stove heater regulators require labs to “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.”

This data enables the EPA, state regulators and industry experts to understand how rigorous – or easy – a test protocol is for stoves of various firebox sizes and designs depending on whether crib or cordwood is used, for example.

In addition, the 2015 wood heater regulations stipulates, “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” to the EPA. Thus whether the tests resulted in certification, or were suspended or failed, the data still goes to the EPA and becomes part of the public record.

However, most labs appear to not always comply with this part of the NSPS and the EPA appears to not be strictly enforcing compliance (NESCAUM as submitted a FOIA request (EPA-HQ-2019-008306) for suspended test reports). This undermines the process of developing better test methods that could result in genuinely cleaner stoves.  In an unusual move, the EPA made a memo to test labs public that detailed lapses in lab test reports.  Filing reports from suspended tests was not among the issues the EPA raised to labs.

The high certification success rate of stoves scheduled to be tested may appear to undermine industry claims that the 2020 standards are impossible or crippling. However, stoves are intensively tested in private or internal labs before they are scheduled for expensive certification testing, as manufacturers need to know that they have a high chance of success to justify the expense. Manufacturers need to be able to repeat the prescribed test protocol relatively consistently to avoid a level of randomness between practice tests and certification tests that could result in repeatedly suspending certification tests. This issue of repeatability is at the core of the entire concept that wood heater testing is a valid and useful way to tell which heater is clean enough to put into homes and communities across America.

The fact that a very high percentage of certification tests are successful may undermine some industry claims that the variability of testing stoves under 2 grams an hour is far too high to render the test useful. Manufacturers have reams of data from in-house testing that could show how close their certification test results were to their practice tests. Some communities, often outside of the HPBA core, are far more transparent in sharing testing data, such as the Masonry Heater Association and various parts of the international cook stove community.

It is unclear if all manufacturers are following the same guidance about filing 30-day notices, as the EPA has become laxer about when wood heaters can be tested. Heaters often face delays in testing due to a variety of reasons, technically requiring a new 30-day notice. One stove AGH found has seven 30-days notices filed for it. Others had only one, but they may have delayed the test multiple times.

Conflicts of interest

An equally thorny issue is the conflict-ridden economic relationship between the labs and manufacturers. Labs want their clients to have confidence that they can get their stoves or boilers to pass the certification test. There is a process leading up to a certification test where labs come to know the strengths and weaknesses of a heater and match those with the areas of flexibility in a test protocol.

Labs guard their privacy and confidentiality on behalf of their clients. Curtains are often used to ensure that visitors cannot see whose heaters are being tested, and when and how. The 30-day notification rule was supposed to enable state or federal regulators to periodically witness certification - announced or unannounced. Witnessing testing allows regulators to understand the complexities, nuances and loopholes involved. Without that understanding, regulators cannot gain the level of expertise necessary to enforce existing rules, much less write better ones.

But here is the rub: AGH is not aware of any federal or state regulator who has witnessed a certification test in the last 5 years.  Rod Tinnemore, a Washington State regulator was one of the few who did witness tests and he gained the expertise, trust and respect of many stakeholders.  After his retirement, Washington appears to have backed off its multifaceted wood heater roles. Certification tests often last 4 – 7 days and can be very boring. Labs exist in only a few states and agencies do not have the time, resources – and sometimes even the authority – to witness testing. Most regulators do not even have the expertise to fully understand what they are witnessing and what nuanced lab practices are allowed or not allowed. The result is nearly a classic catch-22.

Conflicts are also potentially abundant in stove testing protocols like the ASTM E3053-17, which was developed and paid for by many of the same industry players whose stoves will be certified by those methods. Developing a protocol is an expensive and lengthy process, and there is no guarantee that it will be approved for use by the EPA and the EPA can unilaterally modify its use for certification testing. The EPA, however, may not have the resources and data to fully understand the nuances of a new alternative protocol until years later, when enough stoves have used the method. Further handicapping their oversight role is not consistently getting data from manufacturers for suspended tests.

Ultimately, audit testing of stoves in the same and different labs that certification testing was performing will likely be needed to bring attention and clarity that many of these issues deserve.  Audit testing by the EPA and/or states may help all labs ensure that testing parameters are consistently applied.

Similar, but more entrenched conflicts of interest in the European community stove testing community have led to what many experts regard as weak and ineffectual testing regimes. Some fear a convergence of cultures in US and European test labs if the EPA loses more staff and resources, or has its hands tied by appointed officials who favor industry concerns.

Future Challenges

Corporate, religious and educational institutions across America are coming to terms with legacies where people felt they had conflicts of interest and didn’t speak up about infractions and abuses. The VW auto testing scandal is a perfect example because it was in plain sight all along but everyone involved kept quiet. The issues and the stakes appear to be far smaller in the wood heater community, but we are dealing with devices that combust at extraordinarily hot temperatures in our living rooms and basements. When those temperatures are not present, the chimney may be emitting excessive particulates into our neighborhoods. Like the European auto testing community, the wood heater industry is also a relatively small group of seasoned experts, many of whom are older, known each for decades and abide by spoken and unspoken agreements not to publicly criticize others by name or expose issues to authorities.

In the 1970s, many industry insiders had a compelling mission - helping hundreds of thousands of families avoid incredibly high prices and live a simpler life that was more connected to nature and their own hard work. That mission is still a prominent driver for much of the wood heater industry, but instead of struggling to weld together enduring, affordable stoves, they are now filing 30-day notices, 60-day notices and a dizzying array of other paperwork.

One result is consolidation and a banding together to fend off stricter regulations and more oversight. Many manufacturers feel that they need to keep as much data as possible away from the government to survive. When outdoor wood boilers took off, just like when sales volumes of exempt single burn rate stoves soared, most industry insiders stayed quiet publicly, even when they privately fumed over the damage that these unregulated devices were causing to airsheds and the industry’s reputation. Top industry leaders also stayed quiet while highly exaggerated efficiency values proliferated and deployed their lawyers to ensure all stoves could be treated as 75% efficient or higher for IRS purposes.

Issues surrounding 30-day notices and suspension reports are not at the core of the struggle for the future of how well wood heaters work in the hands of homeowners, but they illuminate a slice of the struggles facing industry, EPA, state regulators and the air quality community as our country decides which renewable technologies will power our future. Once represented by the Washington DC based trade group “Wood Heat Alliance” in the 1980s, wood heaters are now represented by the HPBA that also represents more profitable gas and propane appliances and struggles to fit in to the renewable sector that thrives on greater transparency.


1. The 30-day notifications sent to the EPA are currently only being made through a Freedom of Information Act request, rendering them far less useful than if the EPA maintained a publicly available database. This could also provide transparency of key information that is not available elsewhere.

2. If state regulators who have labs in their state visited labs periodically to witness even part of a certification test, it could provide valuable insight and potentially oversight into the nature of testing procedures for states, the EPA and others.

· Oregon is by far the most important state since Omni and PFS-TECO are located there, and has a unique and longstanding role in stove regulation that predates the EPA’s role. The state also has areas where excessive wintertime wood smoke is a serious problem.

· NESCAUM has risen to become the most active and informed entity in the wood heating testing community. Its staff and member states can use their expertise to put pressure on the EPA and assist them in developing future test methods.

· California often plays a large role in national air quality policy, the state has taken a back seat for stationary wood heaters so far. Their engagement could help.

3. Manufacturers should start to routinely comply with the rule that they send a report with data on suspended tests within the required 60-day period. EPA also needs to enforce this regulation and clarify what those reports should look like. HPBA could take a leadership role in highlighting this regulation for labs and manufacturers.

4. The EPA and/or states should start conducting audit testing of stoves to better understand the application of crib and cordwood test methods.  This would assist all stakeholders to focus on vital issues about lab testing during a time when wood and pellet heating is under public scrutiny as a renewable energy solution.

Friday, July 19, 2019

EPA finds lapses in cord wood certification test reports

A Regency stove being tested at RFS labs
for 2020 compliance using the Alternative
ASTM E3053 cordwood method. (NOTE: The

3 photos used in this story are NOT connected
to the EPA memo.  They are just random 
cordwood certification test.)
The EPA recently sent a memo to wood heater test labs and third party certifies about significant lapses in documenting certification tests using the cord wood test method and potentially significant lapses in cord wood testing.  We reproduce the memo below.  

[For the more recent blog on lab testing, 30-notices and non-CBI reports, click here.]

The memo does not specify which labs and which manufacturers are involved and the EPA is not making that public as of now.  The manufacturers involved are being contacted to have labs submit paperwork to the EPA, via third party certifies, who also could have caught the lapses before forwarding documentation to the EPA.  Some stoves may have to do the cord wood emissions tests again.
A Kuma stove using the ASTM
test method at Omni labs
AGH supports a transition to cordwood testing under the assumption that stoves tested with cordwood are more likely to burn more cleanly in the hands of consumers. But cordwood testing of stoves in the United States is still in its infancy and so far there is only the ASTM E3053 test method.  There are still many, many questions about whether the ASTM method can help achieve the emergence of a class of wood stoves that truly operate better in peoples' homes.
AGH asked the EPA to provide us with the memo to test labs when we heard about it.  The EPA promptly sent it to AGH but more often than not, we do not know about memos that go to labs, HPBA and manufactures.  EPA rarely shares many
A Travis stove using the ASTM cordwood
method at Omni lab.
such memos with the wider stakeholder community, that also includes stove retailers, state air quality agencies and others.  We believe documents such as this should be made routinely available by EPA without anyone having to file a freedom on information act request.   
Documentation from test labs to show stoves meet certification requirements go to Rafael Sanchez at the EPA Office of Enforcement and Compliance at EPA's headquarters in Washington DC.  This memo came from a review done by Steffan Johnson, based in Research Triangle in North Carolina.  Mr. Johnson is the Group Leader for the Measurement Technology Group at EPA's Office of Air Quality Planning and Standards,  the Measurement Technology Group provides national leadership in furthering the science of characterizing and measuring air pollutant emissions from industrial sources and is the EPA's focal point for producing validated emissions test methodology.  The Group also provides expert technical assistance for EPA, State, and local enforcement officials and industrial representatives involved in emissions testing.
From: "Johnson, Steffan", EPA
Date: 6/13/19 4:18 pm
To: all EPA Approved Wood Heater Test Laboratories and Third Party Certifiers,

In reviewing some recent test reports that have been submitted to EPA with the intent to certify a wood heater to the Subpart AAA cordwood emissions standard, there are some discrepancies and concerns that we are observing, and we will be asking some manufacturers to revise and resubmit a corrected compliance test report.  At least one of these concerns (noted below) is critical and may require re-testing.  All of these items are important enough to request a corrected report, and we wanted to let all of you know just why you may be contacted by your client(s) with such a request.

  1. We have seen a number of test reports using the Alternate Test Method and ASTM E-3025 that do not identify the species of cordwood used for the com pliance testing.  While it is true that the ASTM method allows selection from a wide list of wood species, the test report must identify the species of fuel used.  This is specified not in the test method but in the General Provisions to EPA 40, Part 60.8 (f)(2) which governs content that must be included in the test report. Paragraph (iii) of this section reads:  “(iii) Description of the emission unit tested including fuel burned, control devices, and vent characteristics; the appropriate source classification code (SCC); the permitted maximum process rate (where applicable); and the sampling location.”

We are asking that test reports that did not identify the wood fuel species burned during a compliance test submit an amended test report to this Agency.  If you are a third party reviewer and have certified such a test report, we request that you include this item, along with other items listed in the General Provisions, in your review checklist. 

  1. We have seen some test reports that reference “manufacturer’s instructions” for conducting the certification test, yet those instructions were not included in the test report.  The requirement to submit this information is to comply with the General Provisions of 60.8(b) and (c).  The guiding principle here is that ONLY the EPA Administrator has the ability to modify a test method for any reason, and these manufacturers instructions do NOT supersede the test method.  Also, the National Stack Test Guidance Document (available here: clearly states that the emissions test report “must demonstrate all information from the test lab such that it is a stand-alone document capable of reproducing the entirety of the test results”.  As such, all information pertinent to the operation of the appliance during the testing must be included in the test report (per 40 CFR 60.534). Also, as such instructions are relevant to how the testing was conducted, this documentation is not Confidential Business Information (CBI). 

We are asking manufacturers that have issued test reports where the manufacturers provided instructions to the test lab regarding appliance operation during the test, and that documentation was NOT included in the emissions test report available to the public, to take corrective action and submit an amended test report to this Agency.  If you are a third party reviewer and have certified such a test report, we request that you now include this item, along with other items listed in the General Provisions, in your review checklist.

  1. We have seen some test reports that contain manufacturer’s instructions that may run contrary to the test method and rule requirements.  Specifically, we have seen instances where manufacturers have directed laboratories to conduct low load testing with air inlet damper settings at “specified distances from fully closed”, meaning that the unit may not be getting tested at the lowest operating rate that a homeowner will have access to during the course of normal daily operation.  Testing at the lowest setting a consumer will be able to operate the appliance in their home is specifically required in 40 CFR 60.534.

Test labs and third party certifiers who are conducting /observing testing where manufacturers provided such instructions AND where you have knowledge that such devices are capable of combustion with air inlet dampers more fully closed than those setpoints specified by the manufacturer review the rule requirements with their client(s) and either select the lowest available setpoint or modify that stove model to fix the lowest available air inflow setting at that specified point, to remain fixed thereafter.  Furthermore, we insist that laboratories and third party certifiers add the requirement(s) of 60.534 to their checklists and take necessary steps to not look past this requirement in the future.  Appliance models found to have been tested in this manner and subsequently certified, will need to be reviewed by EPA on a case-by-case basis.  As a reminder, third-party certification is an attestation that all testing was conducted as specified in the regulation; certification of testing that does not meet the regulatory requirements may result in loss of EPA Approval status.  

  1. We have seen some test reports where cordwood fuel is used to demonstrate compliance, and the dimensions of the “cordwood” very closely match the dimensions of crib fuel.  While we recognize that it may happen that occasionally a wood splitter would produce a piece where the minor cross section is nearly equal to the major cross section of the fuel piece, we expect that this happens infrequently and is not normal for every piece in a fuel load. 

We ask that labs and third party certifiers use pieces that approximate hand-split fuel and not something that seems to be far more selective.  While fuel pieces are ‘selected’ for the test based on size and weight and, to some extent, dimension, we expect to see fuel loads that are more random (in terms of piece-to-piece comparisons) than not.

As always, thank you for continuing to support the EPA Wood Burning Appliance Certification Program.  Please do not hesitate to reach out to us and ask questions, any time, with respect to any certification testing you are undertaking; we are happy to offer our technical direction to help you, and your clients, meet the subpart AAA and QQQQ regulatory requirements.

My best regards,

Stef Johnson

Steffan M Johnson | Leader – Measurement Technology Group | US EPA Office of Air Quality Planning and Standards | Air Quality Assessment Division | 109 T.W. Alexander Drive, RTP, NC  27710 | Mail Drop: E-143-02 | Phone: (919) 541-4790  | Cell: (919) 698-5096