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

DOE offers funding for “state-of-the-art” residential wood and pellet heater R&D

Updated, May 2022 - The DOE has announced a fourth round of funding for manufacturers to design and produce innovative wood stoves.  The funding opportunity is likely to come in early summer of 2022.

Updated on April 9, 2021 - The US Department of Energy has announced its third round of funding for R&D towards more efficient residential wood and pellet heaters.  The funding level is $5 million, the same as it was for the first two years. 

The announcement is part of a larger bioenergy funding opportunity. The timeline for applying is short and requires a concept paper to be submitted by April 30 as a precondition of submitting the full application on June 21, 2021. Applicants will be notified of funding decisions in August and funds will be disbursed in September. To get started, interested applicants should register with the EERE Exchange. 

"The Alliance for Green Heat applauds the DOE bioenergy program for supporting innovation in the wood and pellet heater sector for a third year," said John Ackerly, President of the Alliance for Green Heat. "This funding will help kickstart a new wave of American innovation and ingenuity in wood heater design which is vital to keep wood and pellet heaters competitive with solar and other renewable technologies."

Jonathan Male, the former Director of
the Bioenergy Technology Office at
DOE,  speaking at the 2018 Wood
Stove Design Challenge

The first year, the DOE selected  two companies – MF Fire and ISB Marketing – to receive $3 million for research and development. Both companies are focusing their efforts on how to make stoves cleaner in the hands of consumers through automation – not just in the test lab – which has become widely recognized as the Achilles heel for the millions of Americans who heat with cord wood.

The DOE is trying to fund more than just tweaks and adjustments to traditionally-designed cat and non-cat stoves. Applications that can demonstrate genuine advancements toward state-of-the-art technology that ensure heaters burn well during start-up and reduce the opportunity for human error will have an edge.

Beyond merely preparing for traditional EPA testing, “applicants are encouraged to expand the testing regimen to evaluate performance over the full cycle of residential wood heater operating conditions (representative of how homeowners actually use their residential wood heaters with representative wood feedstocks).”

Areas of R&D interest

DOE listed specific areas of interest, though other innovations are not excluded.

• Novel and innovative residential wood heater designs
• Improvements in automation of stoves
• Wood heater power generation via thermoelectric module integration,
• Modeling and simulation tools, and
• Improvements in catalyst technologies

The second area, improvements in automation of stoves, includes robust sensing technologies and remote control and real-time performance monitoring. Wood and pellet stoves, boilers, and furnaces could all integrate sensors that monitor and control combustion conditions better. The DOE was a core funder of the 2018 Wood Stove Design Challenge that focused on automation and gave them insight into the potential of this area.

Eligibility

DOE has relatively broad eligibility requirements. Individuals, for-profit companies, non-profits, universities, and state, local, and tribal governments can all apply. Foreign entities and companies can also apply as long as they have a US office. Federal agencies and DOE labs, such as Brookhaven National Lab, are not eligible to be prime recipients but could be a sub-recipient of a grant. All work must be performed on US soil.

Cost Share

Applicants must provide 20% of the total project costs. The 20% can include in-kind services or cash from non-federal sources. Cost share may be provided by the prime recipient, subrecipients, or third parties.

Questions

All questions about the FOA must be submitted to: EERE-ExchangeSupport@hq.doe.gov. DOE personnel are prohibited from communicating directly with applicants. All questions and answers related to this FOA will be posted on EERE Exchange: https://eere-exchange.energy.gov.

A Test Protocol for Automated Wood Stoves

Tom Butcher of Brookhaven Lab using
the protocol on the Wittus stove.
Photo: Kittner for Brookhaven Lab.

The fueling protocol used at the Wood Stove Design challenge is like no other.  Instead of filling a pre-heated firebox with a consistent amount of wood, setting it on a single air setting and letting it burn until the fuel is gone, as the EPA does for certification tests, we took a radically different approach.  

We wanted a fueling protocol that included features of how stove operators likely use their stoves, which includes starting from a cold start and reloading several times. But we went beyond that to mimic extreme operator behavior, by loading the stove full of wood and then turning the heat/air setting all the way down, which can put a stove into a temporary or long term dirty, smolder mode.  Our goal was to evaluate whether an automated stove could outsmart its operator - or the lab technicians running the protocol and run cleanly.  

Getting an overnight burn at a low air setting without putting the stove into a short or long smolder mode is something that many good stove operators can do, and good stove design helps them.  Our protocol sought to mimic some extreme modes operators may encounter with their stoves to see how automation can mitigate negative consequences of those extremes . 

The protocol was provided to the teams two months in advance, enough time to make sure that the

Lisa Rector, demonstrating the full
IDC protocol at the Wood Stove
Design Challenge for EPA staff.
Photo, Kittner for Brookhaven National Lab

protocol worked and competitors could request modification but not so much time that it would allow competitors to design directly to the protocol. The goal was  “creating a single test run that incorporates typical use scenarios and incorporates variability both in the operational modes and the fuel use patterns.”  The protocol was not intended to be a predictor of actual overall field performance (as other test method attempt to do), mainly because of the abbreviated nature of the protocol.  Rather, key operational factors were included to evaluate the automated response of a particular stove.

The outlines and purpose of the protocol was discussed by the Organizing Committee of the Challenge and the intensive process of writing it and testing it a lab was done by NESCAUM and Hearthlab Solutions, with assistance from Brookhaven National Lab and funding and support from NYSERDA.  

The protocol was a short, three-hour protocol that includes several reloads, as operators normally reload their stoves during the first three hours.  We are not aware of any other protocol that includes reloads.  We chose three hours because we had numerous stoves that had to be tested multiple times during a five-day period.  If testing crews could complete three tests of each stove, it would enable us to analyze the reproducibility and repeatability of our test results.  

AGH prepared the fuel loads for each
stove the week before the event.
Photo: AGH

Our working proposition was that stoves engineered with automated controls and appropriate and robust response techniques produce more repeatable results than manually operated stoves.  It is still too soon to tell whether these stoves had better repeatability than manually operated stoves.  Data will become available in early 2019 to help us answer these questions.  For background on the testing protocols used at the Wood Stove Design Challenge, click here. For initial results of the Challenge, click here.

We hope that elements of this protocol help EPA, other agencies and industry think through the process of what test methods should try to achieve and how.

Wood Stove Design Challenge – Automated Stove Competition – Stove X

Stove:                          Stove X

Dimensions:                XL x XH x XW

Volume:                       Xft³

Fuel species – beech and/or maple 

Fuel length: X

Start-up 

Fuel load density 4 lb/ft³

Amount of kindling: total amount determined by fuel load calculator  (kindling = 8-10 pieces of kindling weighs 1 lb., length must be at least 50% of test fuel length).

Amount of starter fuel: X lbs. +/- 5% - weight of each piece scaled to stove by fuel load calculator

1.    Stove is empty – no ashes

2.    Amount of paper for starter – 6 full sheets

3.    Amount of kindling is x lbs.

4.    Amount of starter fuel is x lbs.

5.    Fuel loading pattern is defined by the manufacturer’s instructions.  If no instructions are provided, a top-down burn protocol will be used.  For the competition, the manufacturer can build the fuel charge in the stove but cannot light off and will be hands off during the stove testing.  For startup phase – fuel can be loaded in multiple batches, but all fuel must be loaded within the first ten minutes of the phase.

6.    Air settings will be determined by the manufacturer. Up to 2 changes in air settings can be used during the start-up phase. 

7.    Fire will be started with a torch.  Torch can be used for up to 30 seconds

8.    Door can remain open for up to 5 minutes.  Manufacturer will set time and door position prior to competition.

9.    For the first 15 minutes (time starts at light-off), the door can be opened, and fuel adjustments made. A maximum of four fuel adjustments can be made. Door can remain open for no more than 30 seconds per fuel adjustment.  Door must be closed as soon as fuel adjustment is complete. 

10. Phase ends 30 minutes from light off or when there is loss of yellow flame, whichever comes first.  If start-up ends before 30 minutes, it should be noted in the testing comments, but no loss of points will occur.

1^stReload

Fuel load density 5 lb/ft3

The SBI managed to handle
the protocol quite well.
Photo: "Kittner for BNL"

Allowable Fuel piece weight: determined by fueling calculator

Target pieces for load: 4

Fuel load weight: determined by fueling calculator +/- 5% 

1.    Immediately after the end of start-up Phase, open stove door. 

2.    Chop existing wood with a fuel piece and to the extent possible smooth coalbed.

3.    Load 1^stReload charge following the specifications for this phase provided above. 

4.    Fuel loading pattern defined by the manufacturer’s instructions. Options are:

a.    East/west

b.    North/south

c.    Criss-cross

5.    Close door immediately after loading fuel. Maximum time to reload 60 seconds.

6.    Air settings/thermostat immediately turned to low demand

7.    During 1^streload phase one (1) fuel adjustment is allowed.  Additional fuel adjustments can be requested but the total score deduct 2 points for each additional fuel adjustment. Door can remain open for no more than 30 seconds for a fuel adjustment.  Door must be closed as soon as fuel adjustment complete.  

a.    Teams can make recommendations about when and how to make fuel adjustments.  

b.    Additional fuel adjustments interventions can be made at the request of the stove team.  Each additional fuel adjustment results in a loss of 1 points from scoring. 

8.    Air Adjustments - During the 1^stReload phase no air adjustments can be made unless judge(s) determine an intervention is required. Each intervention results in a loss of 2 points from scoring for every x minutes the air settings differ from the protocol. Interventions that result in point loss, will be completed upon request by the stove team.

9.    1^stReload Phase ends after 45 minutes (75 minutes from light-off).

2^ndReload

Fuel load – 2 pieces

Allowable fuel piece weight: determined by fuel calculator

1.    Immediately after the end of 1^stReload Phase, open stove door.

2.    Break up/chop/reposition remaining fuel to the extent possible.

3.    Load 2^ndReload charge following the specifications for this phase provided above. 

4.    Fuel loading pattern defined by the manufacturer’s instructions. Options are:

a.    East/west

b.    North/south

c.    Criss cross

5.    Close door immediately after loading fuel.  Maximum time to reload 60 seconds.

6.    Air settings/thermostat immediately turned to high demand

7.    During 2^ndReload phase no fuel adjustments are allowed. 

a.    Fuel adjustments can be requested but the total score deduct 1 point for each additional fuel adjustment. Door can remain open for no more than 30 seconds for a fuel adjustment.  Door must be closed as soon as fuel adjustment complete.

8.    Air Adjustments - During the 2^ndReload phase no air adjustments can be made unless judges determine an intervention is required. Each intervention results in a loss of 2 points from scoring for every x minutes the air settings differ from the protocol.

9.    2^ndReload Phase ends after 30 minutes (105 minutes from light-off).

3^rdReload

Allowable Fuel piece weight: determined by fuel load calculator

The testing crew for the automated test
protocol.
Photo Sam Kittner for Brookhaven National Lab.

Target pieces for load: 4

Fuel load weight: determined by fuel load calculator

1.    Immediately after the end of 2^ndReload Phase, open stove door.

2.    Break up/chop/reposition remaining fuel to the extent possible.

3.    Load 3^rdReload charge following the specifications for this phase provided above. 

a.    Load large piece first, then small piece, large piece, small piece, etc until no more wood fits in the stove.

4.    Fuel loading pattern defined by the manufacturer’s instructions. Options are:

a.    East/west

b.    North/south

5.    Close door immediately after loading fuel. Maximum time to reload 90 seconds.

6.    Air settings/thermostat immediately turned to low demand

7.    During 3^rdReload phase one (1) fuel adjustment is allowed within the first 10 minutes of the phase.  

a.    Additional fuel adjustments interventions can be made at the request of the stove team.  Each additional fuel adjustment results in a loss of 1 points from scoring. Door can remain open for no more than 30 seconds for a fuel adjustment.  Door must be closed as soon as fuel adjustment complete.

8.    Air Adjustments - During the 2^ndReload phase no air adjustments can be made unless judges determine an intervention is required. Each intervention results in a loss of 2 points from scoring for every x minutes the air settings differ from the protocol.

9.    3^rdReload Phase ends after 75 minutes (180 minutes from light-off).

Disruption Phase:

Optional Phase TBD by organizing committee

1.    No wood is loaded.

2.    Unit is placed in disruption mode, this could be: eliminating power, disengaging catalyst, etc.

3.    Disruption phase lasts 15 minutes.  

4.    Visible emissions may be the only measurement.

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