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.

· 

·       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.

·
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.

New York and Canadian companies win technology challenge to automate the wood Stove

Jonathan Male, director of the DOE's Bioenergy
Technology Office, announces the winners.
Photo: Sam Kittner for Brookhaven National Lab.

(Washington, D.C.) – Two companies with years of experience in electronics and stove design won coveted first and second prizes in the 2018 Wood Stove Design Challenge, held in Washington DC from November 9 – 13. 

Manually operated wood stoves are extremely common throughout the northern US, Canada and Europe but no one has yet popularized a solution to prevent them from emitting excessive smoke in the hands of operators.

Wittus, a company based in Pound Ridge New York, teamed up with German engineers and won first prize for both the automated and thermoelectric categories with a living room unit that also heated water for space heating

The Wittus team who won first place in both
the automated and thermoelectric categories.
Photo: Kittner for BNL.

and generated an average of 161 watts and a maximum of 268 watts over the 2.5-hour test period. Total power output over the test period, net of parasitic losses, e.g., pumps and fans, was 276 watt-hours of electricity. The use of thermocouple sensors and fans facilitated clean and efficient combustion.

Stove testers from Brookhaven National Lab and
New York Department of Health.
Photo: Kittner for BNL.

Second prize went to Stove Builders International (SBI) a Quebec based company that designed 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.

Second prize in the thermoelectric category went to California based Vulcan Energy, who

SBI, a prominent Canadian stove manufacturer
spent years developing automated features.
Photo: Kittner for BNL.

developed a thermoelectric generator for the gravity fed Wiseway pellet stove that generated an average of 123 watts, and a maximum of 139 watts, during the 2.5-hour test period. Total power output over the test period, net of parasitic losses, was 235 watt-hours.

The People’s Choice award, based on votes from the general public, went to 509 Fabrications, for their unique gravity fed pressed log stove.

Key partners in the Challenge included Olympia
Chimney, and CSIA, and NFI installers from
Winstons Chimney and  Sugarloaf Chimney.
Photo Kittner for Brookhaven National Lab.

The goal of the Woodstove Design Challenge is to demonstrate how improved designs including sensors and computer controls can make wood stoves cleaner and more efficient. The technology boom of the past few decades has largely missed the wood stove industry, yet innovation still holds great promise. 

Researchers including Brookhaven National Lab, with support from the New York State

Fred Leavitt won 2d prize in thermoelectric
with Jonathan Male, DOE, Ramesh Koripella,
Sandia National Lab and John Ackerly, AGH.
Photo: Kittner for BNL

Energy Research and Development Authority (NYSERDA), have been developing new methods for the next generation of assessment protocols for wood heating appliances. Currently, most stoves in America are tested for EPA certification with standardized fuel pieces and spacing. Research has focused on in-home use operational practices, user fueling patterns, and new real-time measurement method techniques with random loading patterns and variability in piece size to better replicate real-life conditions.   

Automated stoves that are designed and tested with this new robust cordwood test method can help improve woodstove designs and in-use performance leading to higher efficiency and lower emissions.

Les Otten of Maine Energy Systems with Julie
Tucker of the USDA Forest Service.
Photo: Kittner for Brookhaven National Lab.

A team from Stony Brook University also competed in the event with a prototype that featured a unique wood drying and preheating chamber. The stove did not win a prize but offered students a rich opportunity to engage with national stove design and testing experts. A full list of the competing teams can be found here. 

Partners for the Design Challenge include NYSERDA, the Department of Energy’s Bioenergy Technology Office, the U.S. Forest Service, the Osprey Foundation and Olympia Chimney. The automated stoves were tested by Brookhaven National Lab. A complete list of partners and sponsors can be found here.

Results of the 2018 Wood Stove Design Challenge

 By John Ackerly

The first day of testing, showing Ben Myren Prof.
Phil Hopke and Rebecca Trojanowski.
Photo: Kittner/BNL.

Conducting rigorous and transparent field testing of thirteen stoves in five days is a feat that is unheard of in the wood stove community.  The goals were also unique: fairly test stoves against one another with cordwood; help each team to improve their units and help educate a wider public about novel stove technologies that challenge how we think about the traditional, manually operated EPA certified wood stove.

The 2018 Wood Stove Design Challenge took place from Nov. 9 - 13, featuring 10 stoves in competition and 3 showcase stoves. The stoves were selected and judged by members of the

Large screen monitors provided real time data during
a test run of the Integrated Duty Cycle fueling
protocol under development. Photo: Kittner/BNL

Organizing Committee.  The Alliance for Green Heat (AGH) was the principal architect, organizer and host of the event.  Each of the 10 competition stoves received a $10,000 grant made possible by the DOE's Bioenergy Technology Office.

The Wittus team from New York
and Germany. Photo: Kittner/BNL

In the automation stove category, there were three market ready stoves that successfully went through a rigorous fueling protocol and proved that they could burn relatively cleanly and efficiently even when an operator tried to turn down the heat setting too far and at the wrong times.  An SBI stove and the VcV stove that had been in development for many years showed the value of multi-year R&D and testing, resulting in stoves that may only cost $500 more than a similar,

Staffers from EPA, DOE, USDA and Congressional
offices were able to learn about stove testing and
 engage with teams and judges. Photo: AGH

  

non-automated version.  To us, this is a major breakthrough and stoves like these should show a path to far cleaner cord wood heating in America.  

The SBI team. Photo: Kittner/BNL

The other automated stove was a German-American unit that heated water, made electricity and provided a living room fire experience with a downdraft flame into a lower chamber. While this was not an affordable stove to most Americans, it could have a reasonable pay-back over a number of years, depending on the users cord wood price.  This stove impressed both the Brookhaven National Lab and the Masonry Heater Association testing teams with ultra-low carbon monoxide numbers in the single digits under some conditions, and ultra-high efficiency.  

Ben Myren, one of the top wood stove testing experts
in the US, talking with Larry Brockman of the EPA's
BurnWise program.  Photo: Kittner/BNL

Automated stoves are regarded as one of the best, and only ways to help ensure that manually operated EPA certified stoves perform well not just in the testing lab, but in the homes of consumers.  For automated stoves to start gaining a foothold in the market federal, state and local government recognition and support will be required.

An automated pellet boiler by Maine Energy Systems capped with a Stirling Engine was the most

A Tesla owned by Osprey Foundation head, Bill Clarke,
 being charged by Maine Energy System pellet 
boilers with a Stirling engine. Photo: Kittner/BNL

futuristic of the entries, especially since it was charging a Tesla car in front of the tent. This compact unit could heat a business or multi-family dwelling and provide up to 5 kW of electricity.  

The five testing teams used different equipment
to gather a variety of data. Photo: Kittner/BNL

In the thermoelectric category, the judges concluded that “the most innovative thing is that almost all teams used commercially available thermoelectric modules and showed that it is feasible to generate useful electrical energy without sacrificing the energy efficiency or impeding the heat quality of

This is a Swiss-made electrostatic precipitator for
residential wood stoves that reduced PM by 50 -
90% in our testing.

the wood stove.  Most designs returned the waste heat after electricity generation into useful radiant heat into the room to increase efficiency.  These designs prove that the woodstoves is a good potential commercial opportunity for thermoelectrics to generate useful electrical energy and also increase their commercial appeal for consumers.”

It was clear that stoves or boilers with Thermoelectric Generators (TEG) could produce 100 to 250 watts of power. While this is a relatively modest amount of electricity, larger automated stoves or boilers operating 15 to 20 hours per day may help supplement limited solar power output during winter months. 

Fred Legget of Vulcan Energy 
with a TEG adapted to a Wiseway.
Photo: Kittner/BNL

The George Washington University, Unforgettable Fire and ASAT teams all successfully used off the shelf technology, while TEG expert Fred Leavitt of Vulcan Energy used commercially available TEGs by Hi-Z, and adapted the gravity fed Wiseway pellet stove to get a more steady 130 watt output. 

The Wittus cord wood stove was by far the most market ready and was able to make 250 watts, and it peaked at over 300 when using low moisture pressed wood logs.  Ken Adler, AGH’s Program Director of Thermoelectrics, coordinated the thermoelectric side of the competition and the thermoelectric testing.

University teams have been a key part of the Design
Challenge with SUNY Stony Brook competing this year.

Scoring was done using a numeric rubric based mostly on data produced by the testing equipment but judges did have discretion to award some points based on their subjective assessment in several areas.  Judges assessed automated stoves by these criteria and thermoelectric stoves by these.

And the awards goes to …

The Wittus team won both first prizes.
Photo: Kittner/BNL

·     * First Prize for automated stoves: Wittus.  Great performance on particulate matter, CO, efficiency and safety.

·     Second prize for automated stoves: SBI. A fully automated non-catalytic stove using only 2 sensors that may only cost $500 more than if it were non-automated.

·     * First prize for thermoelectric stoves: Wittus - again;  The highest electric output of up to 250 watts, and an integrated design that can maintain stable electric output.

·     * Second prize for thermoelectric: Vulcan Energy, using the Wiseway pellet stove that produced more than 100 watts and good PM reduction.

Stove testers Tom Butcher, Jake Lindbeg, Rebecca 
Trojanowski Photo: Kittner/BNL

·     Innovation prize: SBI, for simplicity.  The use of only one thermocouple and a sensor on the door, enabled the designers to regulate the stove despite attempts by the testers to turn the heat demand down and make it perform poorly. 

·     * The People’s Choice Award: 509 Fabrications.  Despite being a new, small company without an extensive social media network, the 509 Fabrications pressed log stove was a consumer favorite, garnering more votes than any other stove. 

The MHA testing crew: Ron Pihl, Jim 
Schales, Norbert Senf, Mark Seymour 
and Boris Kukojl. Photo: MHA

Unique and rigorous testing

The 2018 Wood Stove Design Challenge pushed the limits of rigorous wood stove testing both in terms of the amount and variety of technology used, and the fueling protocol, which is far more rigorous than any standard fueling protocol.   More details about this will be forthcoming.  Data produced by this event will show the extent to which automated stoves can navigate fueling protocols where testers try to make stoves go into smolder mode, to see if the automation is robust enough to avoid that.  Data is also more valuable for understanding real world venting conditions, as EPA approved test labs terminate in a warm indoor space, not the colder outdoors.  

Real time emission displays allowed testers teams
and judges to learn more about performance patterns.
This shows exceptional  CO and stack temps on the
Wittus. Photo: Senf

Between Brookhaven National Lab and the Masonry Heater Association, we had up to 5 separate testing teams, allowing many stoves to be tested at once.  We

Jonathan Male, head of DOE's Bioenergy
Technologies Office introducing the awards
Photo: Kittner/BNL

also wanted to have ensure that the Brookhaven and MHA teams could  periodically test the same stove at the same time.  Norbert Senf of the MHA had worked for months to automate the Condar, and the new Condar controls worked very  well, with minimal glitches. They did three runs simultaneously with Brookhaven National Laboratory who used a diluter and Testo 380. Comparisons of the two approaches will be published at some point.

Air quality testing during the Design Challenge

During the Challenge, we monitored indoor and outdoor air quality to get some sense of the impact

Tinted stove pipe donated by Olympia Chimney, 
showing mostly invisible smoke during the event
Photo: Kittner/BNL

from 9 – 13 wood and pellet stoves operating under one roof.  We used a Thermo Scientific pDR-1500 Aerosol Monitor, an Speck indoor PM monitor and a Purple Air PA-II - SD monitor.  Results were mixed, with most indoor readings between 20 - 35 micrograms per cubic meter, but with far higher spikes. The EPA short term PM standard is 35 micrograms per cubic meter.  Outdoor numbers were usually around

Les Otten, right, with Maine Energy Systems
Okofen Pelletmatic E-max CHP unit. Photo: MYSys

10 micrograms per cubic meter. Often the Speck showed  moderate to elevated inside the tent, but on several occasions, prototype stoves released excessive smoke into the tent – and outside of it.  We will issue a more detailed report on this. 

A note of gratitude

Julie Tucker of the USDA Forest Service, with
DOE's Jonathan Male and  AGH's John Ackerly
Photo: Kittner/BNL

 The Wood Stove Design Challenge is a collaborative process involving three major donors - the Department of Energy's Bioenergy Technology Office, New York State Energy Research and Development Authority and Osprey Foundation and scores of in-kind and volunteer partners.  Olympia Chimney and Masonry Heater Association were key in-kind partners, along contributions by West Penn Power

Dusty Henderson with the 509
Fabrications pressed wood log stove
that won the People's Choice Award. 

Sustainable Energy Fund, HPBA, Schott-Robax, Lignetics, Chimney Safety Institute of America, Society for American Foresters, National Fireplace Institute, Catalytic Hearth Coalition, Biolite local sweeps and installers and others were key in enabling the event to occur.  

Unless otherwise noted, photos taken by Sam Kittner and made possible by funding from Brookhaven National Lab and can be used freely by all, with attribution to "Sam Kittner for Brookhaven National Lab."  Photos attributed to AGH can also be used freely and attributed to "Alliance for Green Heat."

The GW University Team. Photo: Kittner/BNL

The innovative rocket stove entry from
ASAT being tested by Ben Myren
Photo: Norbert Senf

Our tent was right between the Capitol and the Washington Monument.
Photo: Kittner/BNL 

Photo: Kittner/BNL