Wood and pellet stove companies that you can trust – and those you can’t

When it comes to listing accurate efficiency and BTU output on their websites, there are only a handful of companies that you can trust.

Updated on January 11, 2018 - For years, wood and pellet stove companies have listed exaggerated efficiencies and BTU output on their websites and brochures and no agency has challenged them for this practice.  Luckily, the EPA has started to list efficiencies on their list of certified stoves, so consumers have a easy way to check company claims.  

Most wood and pellet stove manufacturers use a variety of ways to say their stoves are more efficient than they actually are, and that they put out more heat than they actually do.  BTU output is the other area where manufacturers routinely report misleading data to consumers.  In the case of BTU output, even the EPA was willing to post those exaggerated numbers on its website, further contributing to the problem.

These issues are coming to light in the wake of new EPA regulations that require more accurate reporting and require manufacturers to post the test reports of independent labs that certify wood and pellet stoves.  Many stove manufacturers are not complying with the new rules and will not post their certification reports for consumers to see but some companies are complying.

A few companies stand out for providing the same efficiency numbers to their consumers as the independent test lab provided to the EPA.  They are: Blaze King, Jotul, Kuma, J.A. Roby, Seraph, Travis and Woodstock Soapstone.  Consumers can trust the efficiency numbers that these companies post on their websites and in their promotional materials.  

The same is not true of other companies, including many leading brands.  Most companies list efficiencies using the European (LHV) method, which can produce efficiencies of more than 100% and make their stoves appear 5 - 8 points higher than they actually are.  But some companies go further, publishing efficiencies that are 15 - 29 points higher than they actually are. 

The largest stove maker in the country, Hearth & Home Technologies (HHT), that owns Dutchwest, Harman, Heatilator, Quadra-Fire, Vermont Castings and others brands, published test lab reports for all their brands, several weeks after this blog first came out (in May 2016), which noted that they had not complied.  The company also says that actual efficiency numbers from independent test labs are recorded in the owners manuals in their stoves.  The result is that consumers see the exaggerated LHV efficiency on the brochures and website and then see the real number, often 5-10% lower, in the fine print of the owners manual.

HHT companies provide their lab reports on pages like these for Quadrafire, Harman.  For those and other HHT brands almost all the lab reports pre-dated the new EPA regulations, so actual efficiencies and BTU output are not included.  HHT has declined to voluntarily disclose efficiencies, like companies such as Jotul and Hearthstone have done.

One of the foremost experts in the hearth industry Dr. James Houck, an adjunct faculty member at the University of Portland in Oregon, used to work for Omni Test labs, the most well known test lab in the US.  He says, “Many of the pellet (and cordwood) stove efficiency values have been produced by commercial labs which optimized conditions and calculation methods." 

A wood stove test lab.

Under the new EPA stove regulations, known as New Source Performance Standards (NSPS), labs may be more restrained from optimizing conditions and calculation methods and will be producing more accurate efficiency and BTU output numbers for consumers.  Still, labs are under pressure from their clients to produce the best possible emission, efficiency and BTU numbers, or they may take their business to a lab they think can produce the best numbers.

The new EPA rules are requiring the test labs to produce more accurate BTU output data, which is crucial for consumers to right size the appliance for their home.  The result will be that BTU figures posted by the EPA after May 2015 when the new rules began will be lower than the figures posted before May 2015.  

The EPA has not started enforcing some of the provisions of the 2015 regulations which are being ignored by many companies. And, its enforcement capabilities are slim, a fact that is not lost on the industry that it regulates. State agencies could help enforce the new regulations, particularly for manufacturers based in their states and if stakeholders in the state pressure them to do so.

Under the new rules, an independent lab testing the St. Croix Hastings pellet stove reported that it produced 7,000 – 27,000 BTU per hour.  However, the St. Croix website says the stove produces up 40,000 BTU per hour.  Many manufacturers used to use the BTU input, which is the amount of BTUs available in the fuel, rather than the BTU output from the stove.  But The EPA has been recording estimated and often exaggerated BTU figures on its list of certified stoves for many years and it will be a slow process for them to start recording more accurate BTU figures from new test reports.  The Alliance for Green Heat has urged the EPA to remove all exaggerated BTU data from their list of certified stoves and only post actual BTU output that is determined by an independent lab using an approved calculation.

“The problem with companies using all manner of efficiency and BTU calculations is there is a disincentive to report more accurate numbers that would make your stoves look less efficient and less powerful,” said John Ackerly, President of the Alliance for Green Heat, a consumer focused wood heating non-profit organization.  “The new EPA rules are starting to change what gets posted on its list of certified stoves, but manufacturers can still virtually post whatever they want on their websites and no state or federal agency monitors that, as they do with cars and most consumer appliances,” Ackerly said.

Some companies are beginning to post their lab reports on their websites, so consumers who want extensive technical details can have access to them.  The reports are dense, often long and hard to digest, but can provide useful insights for those who want very detailed, technical information.  Blaze King, Enviro, Kuma and St. Croix were the first to post test lab report for all their stoves.  Jotul and HHT companies Quadrafire, Harman, Vermont Castings, Heat & Glo, Heatilator, Majestic and Eco-Choice now post them as well.   For some companies, such as St Croix, those test lab reports reveal that they have far higher efficiency and BTU numbers in their promotional materials.  Lab reports can also help consumers understand what air settings or power levels their stove is likely to be cleanest, dirtiest, most efficient and least efficient.

Lab reports from testing that was done prior to 2015 usually do not have efficiency numbers or have been whited out.  Some of the posted lab reports are from as early as 1989, are hundreds of pages long and by test labs that no longer exist such as EEMC, Lokee Labs and Northwest Testing.

Advice for consumers:  Beware of efficiency and BTU output claims on websites and promotional literature of wood and pellet stove manufacturers.  The only companies who accurately report their efficiencies on their websites that we are aware of are Blaze King, Kuma and Seraph, Travis and Woodstock Soapstone.  The EPA’s list of certified wood stoves contains more and more actual efficiency numbers and is one of the few reliable places for efficiency information.  Many companies are still holding out disclosing lab reports to consumers.  If you want to be certain you are buying a higher efficiency stove, buy one that discloses their actual efficiency and actual BTU output on the list of EPA certified stoves.  For more information on this topic and a list of stoves that have actual efficiency numbers, check our blog post, A Review of Wood and Pellet Stove Efficiency Ratings.

(This blog will be periodically updated as more data becomes available or if the companies mentioned reply to queries)

Automated Wood Stoves Entering the Marketplace

Updated: Nov. 2020: There are at least a half dozen stoves on the market that are fully automated or have some automated features that are gaining traction.  Many of these features help the stove burn cleaner and are aiming at a demographic looking for easier operation.

We define a fully automated wood stove as one where the consumer can "load and leave" and not have to worry about adjusting the air flow to get an optimum burn.  On all traditional wood stoves, the consumer must adjust one or sometimes two levers that control the air.  Often consumers don't do this well, resulting in poor combustion that fails to maximize efficiency or minimize smoke.  Thus, even a brand new wood stove that performed very well in the test lab can perform very poorly in the hands of an inexperienced or inattentive operator.

There is only one fully automated stoves on the US market and several more that will be released in 2021.   MF Fire, a Baltimore-based company makes the fully automated Catalyst.  It uses electronic sensors to monitor combustion and adjust air flow as needed.  SBI has an automated stove in the final R&D stage and Buck stove is participating in an automated stove project, both of which are funded by the bioenergy office of the Department of Energy.

MF Fire, a small Maryland
company is trying to disrupt
traditional stove technology.

The automation in the Catalyst is a great option for consumers who want to minimize smoke from their stoves and enjoy the ease of automation.  You can more easily leave for the day or go to sleep at night knowing that your stove won't be smoldering away, which is one of the leading causes of excessive pollution from both old and new wood stoves.

The real promise of automation is not to get a hot stove to hit an ultra-low particulate matter number in a test lab, but to improve real-world results by seamlessly optimizing performance throughout the burn cycle, reducing start-up emissions, and even reducing emissions from unseasoned wood.  EPA certification testing does not test for real-world performance, and incentive programs do not yet recognize the positive attributes of automated or semi-automated stoves, so stove companies have not had much incentive to invest a lot of time, effort, and money in developing them.

In Europe, fully automated stoves have been on the market for some time and are beginning to gain wider recognition from consumers and air agencies.  Two companies have advanced automatic stoves that unfortunately are not available on the US market: The Danish company Hwam, who developed the Autopilot IHS, and Austria's Rika, who developed the Rikatronic.  In the United Kingdom, solid burning heating devices are classified by whether they are automatic or manual. To achieve a rating to be used in more polluted areas, manually operated stoves must submit lab tests showing 5 burns for each output level because “manually controlled appliances show much higher variation between tests.”  Automatic appliances only have to be tested 3 times at each output level.  The chart below shows a wide variety of technology that exists in both stoves and boilers in Europe, but only exists in boilers in the U.S. 

In 2013, 2014 and 2018, the Alliance for Green Heat partnered with Brookhaven National Lab to assess and test automated stoves and prototypes at stove design competitions.  Their designers aspire to be part of a real trend towards cleaner, more automated residential wood heating.  But can they do it at an affordable price point?  And, are consumers ready for them?  Here, we look at stoves with partially automated features that are already on the market.

Partial automation solutions

A bi-metal coil acts as a heat-
sensitive thermostat which can partially
control the opening and closing of the damper.

1. The bi-metal coil. One of the oldest forms of automation of steel wood stoves is the bi-metal coil which has been used on scores of stove models and is now mostly just used by a few catalytic stove makers, principally Blaze King and Vermont Castings.  A bi-metal coil is simply a thermostat run by a metal coil that can close a damper down when it's really hot, and open it up when it's cooler. The stove’s air inlet can still be operated manually, but the bimetal coil will adjust the air inlet further. They tend to not work nearly as well on non-cat stoves, because the temperatures in a non-cat firebox can be more unpredictable, and if the coil shuts down the air, or opens it too much, the stove would operate poorly, which adds far too much uncertainty in passing the EPA emissions certification test. A new, more sophisticated version of this technology is the VcV valve developed by a Australian company and Ben Myren.

The rotating trigger mechanism in the
Smartstove Collection by Englander
reduces air flow once the stove is hot.

2. Better start-up: Several companies have features that help start-up: the Quadrafire "Automatic Combustion Control" and the Travis "Green Start."  They all use different automated approaches to starting the fire quicker and with fewer emissions.  After the start-up period, the stove operates like any other.

Quadrafire's Explorer 2 Start-Up air
control helps give the stove more
air in the first 25 minutes.

Another recent arrival on the market is Quadrafire’s Explorer II, which provides a similar automated start-up.  The website says “Automatic Combustion Control-provides the fire with air when it is most needed-leading to longer burns.”  A marketing video says the operation is so easy that all you have to do is “load the wood, light the fire and walk away.” According to the installation manual, ACC is basically a timer which the operator must manually initiate with a control mechanism.  Essentially, it opens the front air channel which allows air to enter for 25 minutes before closing.  Once the front air channel is closed, manual controls are used to deliver preheated air to the top of the firebox to burn the rest of the unburned gases in the remaining three combustion zones.

The slider on the Cape Cod
adjusts the rate of burns.

Travis industries Hybrid-Fire technology™ developed an automated “Greenstart” which shoots 1,400 degree air into the firebox for 15 minutes to start your fire, or when you reload.  The Greenstart can significantly reduce start-up emissions, and emissions during reloading on a low temperature bed of coals, by jumpstarting the start-up process and heating the wood up faster than it would with newspaper.  After the first 15 minutes, the stove has no automated features, but some of the Travis stoves that use catalysts are among the cleanest in the industry.  The Travis Cape Cod stove won second prize in the Wood Stove Decathlon.

3. Remote operation. A remote control device does not necessarily provide any automation to the air flow.  It can just allow you to do it manually from the couch.  However, some like the Nestor Martin’s Efel has a partial “automatic mode” that can keep the room at a desired temperature.  In timer mode, it can adjust the room temperature at a pre-set time. The stoves uses a simple ambient air thermostat in a remote control device that you can operate from the couch or anywhere nearby.  If you don’t use it in automatic mode, the remote control allows the user to adjust the intensity of the fire just as you would with a manual air control. One of the key things that distinguishes this Efel from truly automated stoves is that there are no sensors in the stove that can prevent the stove from smoldering or override an adjustment by the operator that would make the fire smolder.

HWAM's Autopilot technology uses
sensors, along with a bi-metal spring to
regulate combustion temperatures.

Fully automated stove on the European market

1. The final two stoves are more fully automated stoves and are on the market in Europe, but not in the US.  Danish company HWAM has integrated a new patented system: Autopilot.  Along with the Austrian Rikatronic, described below, the Hwam is one of the most advanced and fully automated stoves in Europe. HWAM 3630 IHS features a control system that electronically measures combustion conditions through the use of a lambda oxygen sensor and a thermocouple.  An onboard computer then allocates combustion air through three separate valves to help the consumer achieve the same results at home that are obtained in test labs under ideal conditions.  According to the Danish Technological institute, HWAM stoves with this system are 17% more efficient and produce 40% more heat.

Rikatronic has a microprocessor-controlled
motor and a flame temperature sensor
which drives the RLS air distribution system.
The light tells you the optimal time to reload.
By pressing the button, the stove knows
 it has fresh wood to handle. 

2. There are numerous versions of the Rikatronic wood heater system. The Fox II stove features manual and automatic control settings.  In manual mode the air distribution can be controlled in each combustion phase-even in the event of a power outage.  Automation in Rikatronic technology works with a microprocessor-controlled motor and flame temperature sensor which operates the RLS air distribution system.  Airflow in each of the 5 combustion zones is effectively adjusted for efficient burn.  A red light indicates the optimal time to reload the stove.  You can set the room temperature you want and once the required room temperature is reached, you can activate the eco mode by pressing the Rikatronic³ button.  This causes the air supply to be optimally controlled to maintain the fire for as long as possible, without smoldering, and to leave behind as little ash as possible.  Power consumption is 2 – 4 watts.

A Review of Heating Fuel Calculators: The best and the biased

 Updated on August 22, 2016 - Most people who heat with wood or pellets do so partly because it saves them money.  To demonstrate this, stove manufacturers and retailers often include heating fuel calculators on their websites so consumers can estimate their actual savings.  So far so good.  The problem is that unlike fossil fuel furnaces, wood and pellet stove efficiencies are reported in a variety of ways and most stove manufacturer calculators are biased.  If you are a consumer, this blog will help you find reliable calculators and reliable typical efficiencies of hearth products.

The Alliance for Green Heat reviewed scores of the most popular fuel calculators and found many of them to be hard to use and biased.  Not surprisingly, we found that most heat calculators on commercial sites were biased in favor of the fuel or the stove technology that they were connected with.  Of the dozens of calculators we reviewed, we recommend two that are good for calculating savings with wood and pellet heating appliances: the USDA Forest Service and Hearth.com. (We used to also recommend the Energy Information Agency calculator, but they removed it because of too many controversies over efficiency values, especially from the air source heat pump sector.)

 1.  Hearth.com,  is run by independent hearth professionals and uses efficiency values that are based on available data, extensive knowledge and experience. The efficiency values are on the conservative side, reflecting estimated real world efficiency over time.   Users enter their own price for cord wood or pellets and then can use the suggested efficiencies provided by Hearth.com.   Unlike the USDA calculator, hearth.com uses an estimated 60% efficiency for EPA certified non-cat stoves and for older, uncertified stoves they estimated between 25 and 50% efficiency, depending on if its air tight or not. They provide realistic estimate of 55 - 65% efficiency for uncertified pellet stoves and 65 - 80% for certified pellet stoves.

2. The newly updated USDA Forest Service calculator is notable for including estimated values for both commercial and residential wood and pellet systems.  Like hearth.com, it also provides more options for wood and pellet heaters, such as for uncertified (exempt) pellet stoves, so we recommend it over the EIA calculator. It also uses the outdated EPA default efficiencies, so we recommend using the updated efficiencies below, or the more conservative ones in hearth.com.

We think it’s important for heating fuel calculators to be transparent and show what stove efficiencies and fuel prices they are using, something many industry calculators usually don’t do.   While consumers can easily put in their own fuel costs, it is usually impossible for a consumer to put in an accurate efficiency level of a particular stove.  Few major US manufacturer provide a reliable efficiency of their stoves to their consumers that are clearly American (HHV), not European (LHV) heating values. Consumers should not rely on the efficiency numbers posted by manufacturers. We encourage consumers to use the average efficiency values listed below.

Many fuel calculators that focus on wood and pellet stoves do not disclose the efficiency numbers they use in the calculation so the consumer cannot know what the values and assumptions are.  Harman,  Quadrafire and Travis calculators are a good example of this.  HPBA and most industry calculators do not include a separate efficiency value for catalytic stoves, which have consistently higher efficiencies if they are used properly.

Data on Efficiency

There are some datasets based on standardized wood stoves testing.  Studies from Houck & Tiegs, Robert Ferguson, and OMNI labs are among the best sources available as of now (they are listed below).  Those studies and data sets indicate that non-cat stoves average between 68 and 72% efficient, significantly above the 63% EPA default efficiency that was set in the late 1980s.  There is little data on catalytic stoves, but we think the EPA default of 72% may not be too far off the mark.  We suspect the average today may be in the 75% range, and the most efficient ones that are listed on the EPA list average around 80%.

Theold   EPA default of 78% efficiency for pellet stoves is by far the most misunderstood, because that 78% only applied to EPA certified pellet stoves, not their less efficient cousins, the exempt pellet stoves.  We now know that the default efficiency was too high for both certified and uncertified pellet stoves.  New, certified pellet stoves average about 72% efficiency. An OMNI study found the average to be 68% and EPA tests referred to in paper by Jim Houck estimate 56% for exempt pellet stoves.  There is extensive misleading information about pellet stove efficiency not only from industry, but also from some US government sites.

Efficiencies of Phase 2 EPA qualified boilers range from 39% to 78%, with an average of 65% according to the EPA list of boilers.  An Intertek report cited a 55% average efficiency for Phase 2 boilers and the State of Maine gave them a 65% average.  Efficiencies for European pellet boilers certified to the EN303-5 standard are likely to be in the 75 – 85% range, although some that are oversized or without any thermal storage could be lower.

Non-cat wood stoves tend to be bunched between 65 - 75% efficiency.  However, pellet stoves can range from 45 - 80% efficiency.  Higher efficiency ones are more likely to be the EPA certified or the European pellet stoves.  Unlike non-cat and pellet stoves, catalytic stoves are much more likely to have reliable, actual efficiency levels posted on the EPA certified stove list and that is an excellent resource to select one of the highest efficiency catalytic stoves on the market today.

Wood stove efficiencies discussed here are derived from tests in strictly controlled lab settings.  For consumers, to get similar, optimal efficiencies it is vital to use seasoned wood (about 20% moisture content).

Our Recommendations

Our recommendations for heating fuel calculator efficiencies reflect values of a new appliance when it is being used with seasoned wood. After a year or two, appliances can lose 5 - 15 points in efficiency if they are not properly maintained, particularly boilers, pellet stoves and cat stoves which need periodic cleaning to maintain the average efficiencies listed below:  

EPA certified non-cat stove         70%

EPA certified cat stove                75%

EPA certified pellet stove            70%
Exempt/uncertified wood stove   54%

Exempt pellet stove                     65%

EPA Phase 2 outdoor boiler        65%

Exempt outdoor boiler                 45%

EN 303-5 pellet boiler                 80%

References

Ferguson, Robert. An Evaluation of Overall Efficiency for EPA Certified Non-catalytic Wood Heaters. Rep. Ferguson, Andors & Company, prepared for the Hearth Patio and Barbecue Association (HPBA)., 21 July 2011.

Houck, James E., and Paul Tiegs. Residential Wood Combustion Technology Review. Tech. no. EPA-600/R-98-174a. OMNI Environmental Services, prepared for the EPA Office of Research and Development, Inc., Dec. 1998. Web. .

Houck, James E. "Pick a Number, Any Number." Hearth & Home. N.p., Mar. 2009. Web. .

Li, Victor S. Conventional Woodstove Emission Factor Study. Rep. no. Study. Environmental Protection Operations Division,, n.d. Web. .

The Engineer’s Guide to Efficiency Requirements for Wood Burning Appliances. Rep. no. BPEE201-11. Intertek, n.d. Web. .