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

Alaska building list of properly certified wood and pellet stoves

Lab certification test are designed to
burn as cleanly as possible and all
emission results must now be publicly
disclosed as of 2015.

Alaska Finds widespread deficiencies in EPA wood stove certification process 

Officials in Alaska are in the process of compiling lists of wood stoves and boilers that have met all the requirements of EPA certification and emit fewer particulates during the first hour of the test burn. Alaska regulations requires new wood heating appliances installed in the Fairbanks nonattainment area to meet additional regulatory requirements beyond obtaining a federal U.S. EPA certification. The regulations went into effect January 8, 2020 and Alaska has been working to implement those regulations since then.  The new regulatory requirements involve reviewing certification test reports for deficiencies and collected data regarding additional PM levels and then approve specific models of wood stoves and pellet stoves by updating their approved device list.

The Alaska Department of Environmental Conservation (ADEC) began this process as part of their efforts to address excess wood smoke pollution that contributed to Fairbanks becoming a non-attainment area.  The State’s Implementation Plan (SIP) to improve air quality began including measures years ago to crack down on dirtier wood burning appliances, such as outdoor wood boilers.

The current effort involves reviewing every stove’s certification paperwork to ensure that it includes all the elements that EPA regulations require, such as average CO, the manufacturer’s written instructions to the lab, firebox dimensions, efficiency calculations, burn rate calculations, raw data sheets, documentation of run anomalies, etc. etc. 

 

If you are not familiar with this brewing controversial initiative, you are not alone.  The first time most people outside a small group of manufacturers and regulators heard about this was a month ago, Sept. 18,  when a group of states weighed in on the litigation between HPBA and the EPA.  Their brief mentioned that the Alaska Department of Environmental Conservation was conducting a systematic review of wood-burning devices that have been certified to be compliant with EPA standards. The Department found that 59% of the certifications had inaccurate certification data, and that the EPA must have a way to check on manufacturers through audits. 

The start-up phase of a stove in the lab
should be consistent with how it is
described in the owner's manual.

The lists being developed by Alaska officials only pertain to what can and can’t be sold in the Fairbanks Nonattainment Area, a very small market.  But regulators, manufacturers and test labs we spoke to all say that this is having major repercussions.  For the EPA, it’s a wakeup call that they have not been sufficiently reviewing test lab reports before certifying stoves.  Test labs are under more scrutiny for various practices and are already  being asked by manufacturers to help ensure their tests come in under 6 grams during the first hour.  And scores of manufacturers are scurrying to provide additional information to Alaska and showing them the details that were in their test reports that Alaska officials missed.  

 

One of the main reasons that everyone is paying attention is that most of the people AGH spoke to agree that other states and change out programs could adopt the Alaska lists instead of using the full EPA list of certified heaters.  If more change-out programs, or even states adopt these stricter requirements, the efforts of a small city in Alaska will have greater national ramifications.  Some managers of change out programs that AGH spoke to say they interested to explore ways to identify cleaner cord wood stoves and are uncertain whether the EPA’s reduction from a de facto 4.5 to 2 grams an hour actually resulted in cleaner cord wood stoves. Incentive and change out programs often have adopted stricter efficiency and/or emission requirements and this may represent the next vehicle for those programs to guide how taxpayer dollars should best be used.

 

The last time state regulators made changes that went on to have national implications may have been in 1995 when Washington State adopted a 4.5 gram an hour state standard, when the EPA allowed up to 7.5 grams an hour.  The 4.5 gram an hour limit soon became a de facto national standard and 20 years later, HPBA insisted it was still the lowest that the EPA should go for the 2015 NSPS.  

Non-confidential portions of emission
test reports made the Alaska investigation
possible for the first time.

Aside from developing new lists of stoves that met all the requirements of the NSPS and emitted less than 6 grams for the first hour of all their certification test runs, Alaska is providing a wealth of information to the EPA, NESCAUM and others who are already in the process of developing a new federal reference test method for certifying wood stoves.  Some regulators the Alliance for Green Heat (AGH) spoke to now acknowledge that they see the current system as “broken” and that no one knew it was so broken.  On November 16, Alaska will be making its data public, showing which requirements in the stove certification process are most commonly ignored or overlooked and which ones are complied with.  

 

The data to be released on Nov. 16 includes a two-page data sheet on individual stoves, showing any deficiencies in their test lab reports.   Each manufacturer will have had up to 2 months to review their own sheets and provide corrections to ADEC prior to their public release.  The initial sheets prepared by ADEC have numerous mistakes according to several manufactures AGH spoke to and include many of the data points that ADEC initially said were not in their test report.  Test labs have been helping manufacturers find relevant data in their test reports, and ADEC will continue making corrections before and after Nov. 16.

 

It’s not yet clear if any test lab reports may be so deficient that the EPA could revoke their certification or require that the stove be tested again.  EPA officials are just beginning to grapple with how widespread the problems may be and what they can do moving forward to help fix problems that should have been in plain sight for so long. The EPA has identified and tried to correct some testing deficiencies in the past.  An AGH blog in July 2019 covered an EPA memo asking labs to correct lapses in reports on stoves tested with the ASTM E3053 test method.  This incident may have contributed to greater scrutiny by states including Alaska’s far more in-depth investigation.

An ADEC official taking
air quality readings on top
of a school.

The EPA certifies stoves based on the weighted average of the entire burn but requires labs to also report the amount of PM in the first hour.  Like efficiency, its data that must be collected and reported by the lab to the EPA, but there is no regulatory limit.  The Alaska initiative is making everyone ask whether the first hour of emissions may be an equally important indicator of a stoves cleanliness than the entire burn cycle.  

 

Currently, the way EPA approved test labs test stoves is by using the standard Method 28 or a variation of it. Lab technicians load stoves with an amount of wood based on the size of the firebox and let the fire go until all the wood is burned, which usually takes anywhere from 4 – 9 hours but can be longer.  During the last several hours of the burn, known as the “tail”, there is virtually no particulate matter being released, but those hours are still averaged into the overall calculation, with much be less than 2 grams an hour with cribs, or 2.5 grams an hour with cordwood. 

 

AGH reviewed scores of test reports and found that single PM reading from the first hour could be as high as 20 grams an hour and the average of all the first hour burns could be as high as 10 grams an hour, but it would be less than 2 grams when the cleaner parts of the burn and especially the tail end of the burn was included.  For Alaska, if any single run went over 6 grams, it was rejected.  Since start-up is the dirtiest part of the burn, identifying stoves that have cleaner start-up may help airsheds improve air quality.

 

Test labs that AGH spoke to noted that this will likely have the result of disqualifying a greater proportion of larger fireboxes.  The average firebox size is 2.2 cubic feet and an initial small sample of stoves with average first hour emissions over 6 grams was 3 grams an hour.  One test lab also said that this could disadvantage catalytic stoves that have no secondary combustion during start up prior to engaging the catalyst, which often occurs 20 – 30 minutes after lighting the fire.  Hybrid stoves, however, that use both air tubes and a catalyst are likely to have cleaner start-up, according to test labs.

 

Some manufacturers are angry that a state is using a brand-new emission metric – first hour emissions – that they could have designed for, if they knew it would be used in some markets to regulate stoves.  Now that it has been flagged, manufacturers certifying stoves going forward can try to meet that – or at least urge the lab to build  the type of start-up fire that will come in under 6 grams.  One of the primary goals of a lab is to familiarize themselves with the stove being tested so they can “optimize stove operations during certification testing.” Some regulators fear that this will just become another factor that manufacturers and labs will use to “game the system.”

 

The Alaska initiative will have a far greater impact on wood stoves than pellet stoves.  Extremely few pellet stoves emit more than 6 grams in their first hour and the testing regimen is more straightforward.  Ultimately, only a dozen or fewer pellet stoves may be disqualified by their review, out of the 98 models that are currently certified. Of the 144 currently certified wood stoves, up to a quarter to a third could be impacted.   New outdoor wood boilers are not allowed in Fairbanks already.  They will be reviewing pellet boilers for compliance.

An inversion in Fairbanks that traps
wood smoke close to the ground.,

Next steps

 

As of Nov. 16, Alaska will publish its review on virtually every EPA certified stoves.  On December 1, only those stoves that ADEC found had complete test reports will remain on the approved device list and be allowed to be sold in Fairbanks.  If a manufacturer needs more time to address potential report deficiencies, they can contact ADEC and if they commit to working to correct the deficiencies, their device may remain on the approved device list.  The first hour emission of 6 grams on each test run requirement, went into effect on September 1, 2020, and those devices have already been removed from the approved device list. 

 

Other jurisdictions, incentive and change-out programs will likely begin assessing whether the Alaska list represents better stoves for public funding.  Consumers who really care about a cleaner stove could also check that list before buying a stove.  For now, there are more questions than answers but the bottom line for everyone in the industry and the wider renewable heating community is that this is a story to watch.

Related stories

Veteran lab technician challenges Alaska's wood stove criteria (March 2021)

Alaska releases deficiency details on wood and pellet stove test reports (Nov. 2020)

HPBA 2020 Expo showcases all new stoves to smaller audience

Jack Goldman, right, opens the 2020
Expo in New Orleans.

Updated, April 9, 2020: The hearth industry’s annual marketplace for manufacturers and retailers concluded on March 14^th, a half a day early in New Orleans amidst a dwindling crowd and growing concern about the spread of Covid-19. This was the first hearth industry gathering since the late 1980s in which virtually all the stoves and boilers on the floor were newly redesigned and tested to meet stricter emission standards.  

Some manufacturers were clearly proud of what they felt were genuinely cleaner stoves while others were unconvinced or cynical of the new standard’s impact in the real world. 

Mark Shmorhun of the DOE's
Biotechnology office
attended the Expo to talk to
manufacturers about R&D
funding needs.

Due to Coronavirus concerns, Travis and Jotul, two large manufacturers, pulled out at the last minute, leading to a notably smaller Expo. U.S. Stove, having dropped their HPBA membership, decided not to attend this year, presumably because their inability to meet the 2020 emission standards on most of their appliances weakened their position in the hearth industry.  US Stove has 18 stove models that are 2020 compliant but no 2020 compliant furnaces yet, an area it had once domoniated.  US Stove responded to this blog, saying they are well positioned to move forward with a broad range of new and exciting products.

From the perspective of the Alliance for Green Heat, the 2020 Expo showcased several notable trends, some encouraging and others troubling.  

Vesta gives Best in Show award to an automated wood stove

Possibly the biggest highlight for AGH was seeing automated stoves take more of a foothold in the marketplace. Napoleon’s Eco Smart wood stove won Best in Show at the Vesta Awards, marking the first time that an automated stove won a Vesta Award.  The stove has an optical sensor that monitors particulate matter and can continually adjust air settings to produce a cleaner burn. According to Napoleon, the automation will only add $300 to the price and they expect the complete system with stove to retail for about $2,500. The stove also connects to the Napoleon cloud via the user's smart phone so they can monitor combustion conditions. The user can also allow the company to log data from the stove, providing a valuable record of how the stove runs. The stove is not yet EPA certified, but should be within months. 

The Charnwood Skye 2700, expected to
retail for about $3,300, several hundred
more than its non-automated cousin.

Charnwood, a British manufacturer, also was a finalist in the Vesta award, with their Skye E2700, also an automated stove that does much of what the Napoleon does, but with different technology.  Charnwood will be entering the US market for the first time later this year with this stove. Hugh Wells, head of the Britsh company told AGH, "We are very excited about this product because it does revolutionise how we burn wood by taking out user error." CFS-Teco did the certication testing in Portland and it achieved 78% efficiency, the highest of any non-cat. 

SBI should also have an automated stove on the market within a year, and MF Fire had their automated Catalyst on display at the Expo and have another one in development.  Maxitrol also exhibited a prototype of an automated stove and says that they are taking off in Germany.  Napoleon also won a second Vesta award for their novel "Heat & Cool Electric Fireplace," a mini-split heat pump housed in an electric fireplace.  

2020 stove trends

The 2020 NSPS has resulted in many more catalytic and hybrid stove models. AGH is particularly

Larry Brockman from the EPA's
voluntary Burn Wise program
talks the MF Fire staff about their
automated stove.

happy to see more hybrid models as they help reduce start-up smoke and provide back-up secondary combustion if the operator does not engage the catalyst. A more unnoticed trend is the rapid adoption of the ASTM E3503 cordwood test method. Data from the EPA list of stoves shows the average grams per hour for cordwood tested stoves is 1.6 grams – the exact same average for crib tested stoves. About 45% of all 2020 certified wood stoves were tested with the ASTM cordwood method, which reportedly has more flexibility in its parameters making it easier for manufacturers to pass the certification test. Nearly all of the smaller non-cat stoves were tested with cordwood. Quite a few very affordable stoves that sell primarily in big box and hardware stores are passing the 2020 standards, and some stoves barely had to undergo any redesign.  

A sophisticated, lower priced electronic precipitator

ESPs for wood stoves, considered
far-fetched just a few years ago, are
improving rapidly and popular in
Germany and Switzerland. 

Danish manufacturer Enervex brought a self-cleaning electronic precipitator, known as an ESP. They are commonly used by factories and restaurants, but now small and affordable enough for residential applications. ESPs are a type of scrubber that uses static electricity to remove particulate matter from exhaust fumes before the particulates exit the smokestack. Enervex’s innovation is to design a residential ESP that is self-cleaning, often a big problem, and to bring the price down. They expect theirs will sell for $1,200- $1,600 when it comes on the US market. There is a quickly growing market for them in Germany, now that they are recognized by the country's eco-label, Blue Swan, and some cities may require them. OekoSolve, a Swiss company, made the ESP being tested in Fairbanks.

HPBA recruits Appalachia Service Project to take 2015 stoves in May

To address the fate of potentially hundreds of wood stoves that are 2015 certified but not allowed to be sold after May 15, 2020, HPBA negotiated with the EPA to allow retailers to donate stoves to a non-profit who can them install them. HPBA is teaming up with the Christian ministry Appalachia Service Project, based in Tennessee, who repairs homes in Central Appalachia, making them warmer,

AGH President John Ackerly with
Adam Bean of the Appalachia
Service Project

safer, and drier. At the Expo, AGH met with Adam Bean, Home Repair Coordinator for the group, who is quickly learning about wood stove installations and trying to estimate how many stoves his group has the capacity to install, which will partly depend on securing donated NFI installing and training.

Pellet stoves out of the limelight

Even though pellet stoves were relatively easy to redesign and test at 2 grams an hour or lower, the market for pellet stoves has not been particularly good and there were not many on the Expo floor. There were no pellet stove finalists in the Vesta Awards, which may indicate a pause in innovation in the North American market.

EPA announces final NSPS rule during Expo

On the first day of the conference, the EPA formally announced that they would not allow a retailer sell-through. The EPA had said on October 15, 2019 that entities should follow the compliance dates but some felt that there was still a chance for a sell-through. HPBA expressed its disappointment in a written statement while the Pellet Fuel Institute claimed a victory because the EPA removed minimum requirements from pellet fuel while retaining the prohibition that pellet fuel must not contain any of the prohibited fuels listed in the 2015 NSPS. There remains considerable debate about whether the 5-year timeline would have been enough if manufacturers had started redesigning and testing to the 2020 standards early in the process. Key excerpts of the EPA ruling provide detailed insight into why the EPA did not allow a sell-through. Some did start early and began offering 2020 compliant models to their retailers as soon as 2018, while most did not start releasing 2020 models until 2019 or even this year.  The issue was far more complicated because manufacturers had large inventories of 2015 stoves and some needed the cooperation of retailers to buy their 2015 inventory well into 2019. An HPBA mailer to retailers in 2019 said: “retailers and distributors should NOT immediately stop buying anything that doesn’t meet Step 2” in part because there wasn’t enough variety and in part because manufacturers still needed revenue from sales of their 2015 inventory.

EPA holds 3-day wood smoke workshop

One of the main reasons AGH attends the annual HPBA Expo is to participate in workshops

The wood smoke workshop brought
scores of experts from across the US
to share new knowledge, tactics and
success stories.

organized by the EPA on wood smoke reduction strategies. This year the workshop was coordinated and supported by EPA's Burn Wise, the Western States Air Resources Council (WESTAR), the Northeast States for Coordinated Air Use Management (NESCAUM) and National Tribal Air Association (NTAA) and was going to be the largest one ever, with nearly 100 federal, state, local and tribal participants registered.  But some states like Washington banned their employees from travel and many other participants cancelled, leaving a group of about 60. The workshop mainly consisted of a series of talks and powerpoints about change out programs, cord wood test methods, the impact of the NSPS, DOE funding opportunities for stove R&D, retrofits and ESPs, low cost consumer air quality sensors, indoor air quality issues, addressing wood smoke complaints, etc. Most of the powerpoints can be dowloaded here. AGH also hosted a gumbo and etouffee networking reception on Frenchman Street for all the participants. 

The 2021 HPBA Expo is scheduled for March 4-6 in Nashville, Tennessee.

EPA releases long-awaited searchable wood heater database

A screen shot of part of the
navigation of different fuel types
in the new EPA database

Consumer friendly site is cause of worry for some

Updated Dec. 2020  - The EPA released its long-awaited searchable stove and central heater database, overhauling a decades-old practice of using basic excel sheet lists.  The database is now a very user friendly site for consumers and all stakeholders.  A simple search that could have taken hours, now takes seconds.

The EPA said the new database was designed to“improve accessibility and usefulness” by allowing users to search for the cleanest stoves, the most efficient stoves, those designed to burn cordwood and other attributes.

A wide range of stakeholders, from industry to states to non-profits, had been urging the EPA to switch to a modern searchable format for nearly a decade. The painfully slow development of the database at times seemed to epitomize the government's reputation to move at a snail’s pace. The list is maintained by the EPA’s Office of Enforcement, which like much of the EPA has been hit with repeated budget cuts and loss of staff in recent years.

The sleek new functionality of the list, allowing users to focus on one parameter or another, is also worrying to many in the stove industry. Traditionally, this list of certified wood heaters has not been a primary information source for consumers. But with this new functionality, consumers may start relying on it more and more, leading to some unintended results, such as worse buying decisions or ones that favor some manufacturers over others.  Similar to the feature in the old excel spreadsheets, the new database now also indicates new additions.

One fear is that consumers will put too much reliance on higher BTU output if they can easily search and cross reference by these values. Right-sizing a stove is already problematic, and the BTU values on the list are overinflated due to loose parameters that allow labs to show high BTU output. Another fear, expressed by some manufacturers at the recent HPBA Expo in Nashville, is that consumers will favor “Cord Wood” stoves over “Crib Wood” stoves because they are not familiar with the lexicon of stove testing and the legacy of crib wood. 

The EPA chose to include a box that helps consumers identify the cleanest and most efficient stoves,

and some say that this puts unwarranted attention to values that won’t necessarily translate from the lab to the home. This “Quick Searches” box will likely be used by consumers who don’t understand pellet stoves work similarly in the home as they do in the lab, but wood stoves can only achieve the optimal lab numbers with a large bed of coals, dry wood and careful operation.

This “certified fuel type” feature also sheds light on one the biggest problems with the new searchable data – accuracy. Six wood stoves were initially listed as using wood chips as a fuel, an apparent mistake according to one of the manufacturers of those stoves. As of November 2020, two stoves are still listed as being tested with wood chips, even though no such test method exists. This could hurt sales of those units if consumers are relying on the database to narrow down the stoves they may purchase. EPA staff are quick to say that this is a work in progress and it is incumbent on manufacturers to vet the list and provide the EPA with corrections. In 2017, the HPBA warned the EPA that many inaccuracies existed in the database. Many of the same errors are still listed two years later.  A whole new frontier of recognizing deficiencies is now being opened up by an Alaska initiative that is reviewing all certification documents.

The Alliance for Green Heat welcomes the new database and had the opportunity to provide input on several occasions as other stakeholders did. Some of our suggestions and wording was adopted and some was not. AGH believes that the new database will help consumers become more educated about the working of stoves and the terminology, but it will take time and effort by the wood heating community.  AGH is currently urging the EPA to add a column showing what test method was used to identify single burn rate stoves and stoves that used an alternative test method.

The release of the database was coordinated with the update of some key pages on the EPA's Burn Wise website. The EPA finally changed their page on hydronic heaters which previously defined and pictured them just as outdoor boilers, a change that AGH had urged them to make for years. They also made major changes to their efficiency page which had not been updated since the EPA began requiring testing and reporting of efficiency of stoves.

Features and functions

·      Pellet stoves

The database shows 98 out of the 242 models are pellet stoves.  Nearly half of the  pellet stove models are 1 gram or under.

·      Catalytic Stoves

The database shows that 30 of the 144 models are catalytic, and another 19 are hybrids which also use catalysts. 

·      Hybrid Stoves

Wood stoves are divided into three
subtypes - cat, non-cat and hybrid.

Hybrid stoves, which almost all use both catalysts and air tubes for secondary combustion, are listed as a subtype and  there are now 19 stoves listed as hybrid. AGH is urging the EPA to also add “automated stoves” as a subtype in the future. Both hybrid and automated stoves offer great promise to help consumers run stoves more cleanly.

·     Cord vs. Crib wood
                  As of Nov. 2020, 83 of the 144 wood stoves were tested with cord wood, indicating a surging popularity with the ASTM test method, that allows more flexibility in the lab.

      BTU Output

With tighter homes and a new breed of tiny homes, it is now easy to search for stoves with the lowest BTU output. Many models are tested at less than 25,000 BTU. AGH believes that many units still have erroneously high BTU values based on loose parameters in lab testing and reporting, and these values should be used with great caution. 

Firebox volume

The cubic size of the firebox is an equally useful tool to estimate BTU output.  They range from 0.5 to 4.4 cubic feet. AGH has concerns that some BTU output figures are exaggerated due to the allowable calculations that labs can use to estimate heat output.  Small fire boxes are usually considered to be up to 1.5 cubic feet and good for holding a fire for no more than 4-6 hours.  Medium fireboxes are in the 1.5 to 2.5 range and usually can hold heat for 6 - 9 hours and large fireboxes are 2.5 - 4.5 cubic feet and can easily hold heat overnight.

Test method

In December of 2020 the EPA added a column to designate the test method that was used to determine emissions, but they have not yet populated the column with any data. This will help better understand which are single rate burn stoves, for example, and which stoves got variances.  The detail will be too technical for the average consumer but useful for stove geeks and agencies.

·      Efficiency

The EPA has chosen to use the term “overall efficiency” instead of simply “efficiency.” Some manufactures use “optimal efficiency” or “maximum efficiency” instead of publishing the EPA tested efficiency, which is lower. One hundred out of 244 models tested at 75% HHV efficiency or greater.

·      Carbon monoxide

Like efficiency, carbon monoxide is required to be tested and publicly disclosed, but there is no regulated minimum or maximum that must be met.  The CO listing raised concern from some who worry that consumers may use it instead of PM as a primary indicator of cleanliness, or that consumers may think it’s an indication of amounts of CO emitted into the room.

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·       Previously certified

The database also shows the 205 stoves that were previously EPA certified at 4.6 grams or higher, a feature that could be very helpful for change out program managers who want to target older certified stoves, many of which need replacement.

·      Key terms and definitions

The EPA provides a new page with definitions of key terms such as adjustable burn rate vs. single burn rate heaters, fireplace insert, wood pellets, etc.

·      Central Heaters

The database is separated into two: “Room Heaters” and “Central Heaters” and you have to select one or the other or your search may turn up empty. There are 32 central heaters with 12 that use pellet fuel.  Of the 32 heaters, only 3 are forced air furnaces.

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Not included in the new database

Some stakeholders have urged the EPA to include more search attributes, such as the test method, lab, and a link to the detailed lab report that manufacturers are required to post on their websites. The list also does not say whether PFI certified pellets were used during certification testing and are thus technically required to be used by the consumer.  Up until 2007, the list used to include the deadline that the five year certification certificate expired.  Up until the summer of 2015, the list included the outmoded estimated default efficiencies, which listed all non-cats at 63%, cats at 72% and pellet stoves at 78%.  The default efficiencies were set based on testing in the mid and late 1980s, resulting in relative accurate estimates for wood stoves, but helping to develop the enduring myth that pellet stoves had such high average efficiencies.

Contact Rafael Sanchez at the EPA's Office of Enforcement to address errors or omissions in the database, (sanchez.rafael@epa.gov) at (202) 564-7028.