The Sensor Surge: Why Equipment Engineers Are Adding Sensors Everywhere — and Why the Wood Stove May be Next

MF Fire is the US industry leader in
integrating sensors into wood stoves

Over the last decade equipment engineers have been rapidly adding sensors to cars, HVAC systems, laundry machines, refrigerators and other household appliances. That trend isn’t just about bells and whistles — it’s driven by lower sensor costs, smarter processing at the edge, connectivity, regulatory and efficiency pressures, and real customer value. Below is a concise look at the benefits, the sensor types being deployed, why prices are falling, where the trend is headed, and how this sensor wave will likely soon be more widespread in something old-school: the wood stove.

Sensors have slowly started to enter the wood stove technology space and are catching on in Europe much faster than North America.  In the US, the Baltimore-based MF Fire made an after-market device with funding from the Department of Energy that represents the most sophisticated use of sensors for wood stoves.  At least one big European stove brand, Jotul, with a major footprint in the U.S. are releasing stoves with automated combustion control only in the European market. 

In 2025, Ecodesign suggested that automated combustion control (ACC) should become mandatory on all new stoves, a suggestion that presumably comes from studying the Blauer Engel (Blauer Engel, 2020) certification. This sent a kind of a shockwave through the stove manufacturing industry, and resulted in industry pushback.  The Nordic Ecolabelling system, representing five countries, is considering requiring ACC in new stoves, or other technology innovation. 

According to a 2025 report from Nordic Energy Research, "In Europe, fully automated stoves have been on the market for some time—for example, RIKA (AU) since 2007 (RIKA Rikatronic, 2025) and HWAM (DK) since 2012 (HWAM, 2025)—and are beginning to gain wider recognition amongst consumers and distributors. The Rikatronic technology (now Rikatronic4 as the latest version) was introduced by RIKA of Austria in 2007; it integrates temperature sensors and electronics to control the air supply and advises when another wood log should be put on the fire through a light visible at the front of the fireplace. This seems to be the most advanced technology for a batch fed or manual wood log burner in terms of automating the reloading and ensuring optimum firebox temperatures for reducing emissions."

There are now more than 10 wood stoves with ACC on the market in Europe, with many in the range of US$2,500 - $4,000.  The best selling automated stove in the world may be the Connect 556 made by Contura a major Swedish stove manufacturer.  Once wood stove certification tests become stricter than they are today in the US and Europe, automation is likely to be the safest way to pass the tests.  Otherwise, the inherent variability in combustion in manually operated stoves will not leave any comfortable margin to passing emission tests.  Currently, stove certification labs on both continents have been able to develop the expertise to pass emission tests without hardly any record of stoves failing the test.

European retailers are also starting to advertise the benefits of automated stoves, socializing the technology benefits to consumers, retailers and the wider community concerned about the health impacts of residential wood smoke. But wood stoves still lag far behind other heating and combustion devices when it comes to embracing the adoption of more and more sensors.

It is important to distinguish full automation in wood stoves from partial automation. Full automation means that the stove has no lever for the operator to adjust air flow, unless the onboard computers can override and optimize the stove for emissions, before responding to the user adjustment for more or less heat. With partial automation, the stove still has a lever or handle to adjust airflow, and the stove has some technology to make minor adjustments in air flow.  The bi-metal coils in Blaze King stoves could be considered partial automation, along with the valves in Pacific Energy Neo stoves. Partial automation, often achieved with the need for electricity, appears to only offer minor benefits compared to fully automated stoves.

Without automation, there is
virtually no way to predict the
performance of a stove 
once it leaves the lab.

Air quality agencies in the U.S. – from the EPA, to NESCAUM to state and local agencies – have been focusing on the shortcomings of the certification process and on designing a better testing protocol.  But US institutions are far behind Europe in studying and promoting automation in stoves.

One of the most obvious benefits of ACC is to prevent overnight smoldering along with speeding up the start-up of the stove. But it may be the safety aspects – producing less creosote and safety sensors that offer peace of mind to homeowners (and insurance companies) that will drive innovation.

From 2013 – 2023, the Alliance for Green Heat ran a series of Design Challenges with the Brookhaven National Lab, and funding from NYSERDA, the Department of Energy and Osprey Foundation that sought to accelerate research and production of automation in wood stoves. Some of the contestants, such as MF Fire, have gone on to get that technology into the marketplace with the Fire MAPS Smart Fire Assistant. 

Why sensors are being added:

• Improved safety: early detection of hazards (overheat, leaks, CO) reduces fire and poisoning risk.
• Energy efficiency and emissions: feedback lets systems run only as hard as needed (modulating burners, variable fans).
• Predictive maintenance: sensors spot component wear and anomalies before failure, lowering downtime and service costs.
• Better user experience: remote monitoring, diagnostics, adaptive settings, and automated schedules.
• Regulatory and reporting needs: emissions, indoor-air-quality (IAQ) monitoring, and energy reporting demand measurement.
• Data-driven product improvement and new services (e.g., subscription performance monitoring).

The use and benefits of sensors are different for each
application based on the risks that application faces.

Common sensor types now used in consumer equipment

• Temperature sensors (thermistors, RTDs, digital temp ICs) — ubiquitous in HVAC and appliances.
• Pressure sensors — used for refrigerant systems, combustion chambers, and airflow measurement.
• Humidity sensors — for IAQ, laundry cycles, and HVAC control.
• Gas sensors (CO, CO2, O2, NOx) — safety and emissions control in furnaces and cookers.
• Particulate sensors (optical/laser) — measuring PM2.5/PM10 for IAQ and emission controls.
• Flow sensors (air and liquid) — ensure correct ventilation, fuel, and coolant flow.
• Vibration and accelerometers — detect mechanical faults in compressors, pumps, motors.
• Current and voltage sensors — monitor electrical health and detect stalled motors or short circuits.
• Optical and camera sensors — visual inspections, flame detection, and product state recognition.
• Position and angle sensors — actuators, dampers, and valve control.

The steady growth in the use of sensors is driven by
safety, consumer appeal and benefits to manufacturers. 

Why sensor prices are falling

• MEMS and semiconductor scaling: MEMS fabrication and CMOS integration drive down unit cost and size.
• High-volume consumer markets: smartphones, wearables, and automotive volumes subsidize production for other markets.
• Integration: multifunction sensor packages combine temperature, pressure, humidity, and motion on a single die, lowering BOM cost.
• Standardization and modularity: off-the-shelf sensor modules and cloud-friendly firmware speed integration and reduce engineering cost.
• Wireless and low-power tech: cheaper connectivity (BLE, LoRaWAN, Thread) reduces installation complexity and cost of retrofits.

Is the trend likely to continue? Yes. Expected drivers:

• Continued unit-cost declines and richer sensor fusion capabilities.
• Edge computing and tiny ML: more intelligence on-device reduces data bandwidth and privacy concerns.
• Stricter efficiency and emissions standards worldwide.
• Growing consumer demand for smart, connected products and services.
• OEMs monetizing data and offering remote service/subscription models.

Expect more sensors per device, tighter integration with controls, and better diagnostics.

HVAC sensors are dominated by temperature sensors, which 
in wood stoves are usually Type K thermocouples that 
typically cost a dollar or two.

Is this trend likely to come to wood stoves? Yes — and in multiple practical ways:

The increased use of sensors in stoves is likely for many reasons, not least of which is that they should make it easier to pass new certification tests in the US and Europe. Automation directly address the IDC’s challenge of consistent, repeatable combustion across varied loads and user behavior. That could make automation an attractive technical route to meet performance targets reliably. However, many manufacturer don't have experience with sensors and will likely want to optimize passive design, secondary combustion, or catalytic systems rather than add electronics.

The biggest hurdle in the short term is that government regulators in the US and European countries often do not have the expertise, resources or clout to overcome resistance by industry to changes leading to improved test methods and stricter emission limits. The US currently has an industry friendly, anti-regulatory administration, which could mean individual states get more involved.

Politics aside, the sensor boom is applicable in wood stoves in obvious ways:

• Combustion efficiency: O2, CO, and temperature sensors can enable feedback-controlled air supplies to keep burn in the optimal stoichiometric window, increasing heat output and reducing fuel use.
• Emissions reduction: particulate sensors (optical) and CO monitors can detect smoldering or incomplete combustion and trigger corrective measures (adjust draft or alert the user), reducing smoke and creosote formation.
• Safety: CO sensors and high-temp cutoffs can warn of dangerous conditions or auto-shutdown linked to ventilation failure.
• Draft and airflow control: pressure or differential-pressure sensors across the stove and flue help manage draft for steadier burns.
• Predictive maintenance: temperature profiles, and smoke signatures can indicate gasket wear, or creosote build-up.
• Remote monitoring and automation: smartphone alerts, remote adjustments to air dampers or blower speeds, and usage logging for fuel optimization.
  
  

  

  In the US, the Department of Energy is
  also supporting important automated 
  stove research at Nordica McCarthy's
  lab at Oregon State University

Practical considerations and challenges for wood stoves

Wood stoves present unique challenges because they use a solid fuel with very diverse characters, unlike electricity liquid fuels. In addition:

• Harsh environment: soot, ash, high temperatures and corrosive gases require rugged sensors and protective housings.
• Sensor placement: measuring combustion gases accurately often needs sampling ports or heated lines to the sensor; fouling is a risk.
• Power and connectivity: many stoves are off-grid or in remote cabins; low-power sensors and local edge logic are important. The ability of the stove to work without electricity/sensors is important.
• Cost vs. value: retrofit kits must be affordable and simple; OEM integration at manufacture yields better reliability.
• Certification and safety/regulatory acceptance: devices that influence combustion or safety need testing and standards compliance.
• User behavior: alerts are useful only if users understand and act on them; automation helps and users are learning from all the other sensor interactions in their daily lives.

Jotul says this stove "continually
monitors  temperature  and
automatically  adjusts  air supply  to
optimize combustion — giving cleaner,  more
efficient burning  and reduced emissions."

How this could be deployed

• OEM integration: manufacturers build sensors and control loops into new stoves (best performance and reliability).
• Retrofit modules: compact sensor packs (temp, CO, O2, particulate) with a local controller and optional wireless gateway for older stoves.
• Service-focused models: subscription diagnostics for stoves used in rentals, remote cabins, or commercial premises – or in any stove where the user wants greater peace of mind.
• Simple consumer features: auto-damper control, burn-stage alerts, and CO alarms tied to phone notifications.

Bottom line: Falling sensor costs, smarter edge processing and connectivity are driving a widespread sensor adoption in vehicles and home equipment — and that momentum should continue. Wood stoves are a natural candidate for the next wave of sensor-driven improvements: safer, cleaner, and more efficient burning is technically feasible today, but practical rollout requires rugged sensors, thoughtful placement, simple user interfaces, and standards-compliant designs.

Innovation in stove technology will also be driven by public health concerns. If wood stoves continue to be popular or become more so due to rising heating fuels - electricity, gas and oil - there will likely be more pressure on governments to do a better job at certifying new stoves. However, global warming is making winters warmer, reducing heating bills, which typically reduces the use of wood stoves, which in turn may ease pressure on air regulators.

Safety recalls of wood and pellet stoves

Updated: July 2022 - There have been at least seven recalls of wood and pellet burning products since 1979 and one certification revocation.  Four of those were in 2015-2016.  While there are few reports of any injuries, recalls are expensive and time consuming for stove manufacturers.

(In addition to stove recalls, the Consumer Product Safety Commission recalled a camping tent sold by Cabellas in July 2022 because the "stove jack ring" where the stove pipe exits the tent, can deteriorate.)

Almost all recalls are voluntary, which is usually to the benefit of the company.  A successful recall effort often reaches about 65% of consumers, and it the case of wood or pellet stoves, it may depend on who sold them and how much effort the company actually made.  Its easier for some stove manufacturers to track down who purchased a particular stove if it was purchased through a specialty retailer compared to stoves purchased through hardware chains.  For the following seven recalls of wood and pellet stoves, there is no data about how effective each recall was.

The dangers posed by some of the stoves subjected to recalls are significant but may pale in comparison to the ongoing dangers of self-installed stoves that never get inspected.  The Consumer Product Safety Commission (CPSC)'s 1982 survey of more than 2,000 households indicates that 70% of stoves in use were installed by the consumer, and half of these "do-it-yourself" installations were never inspected by a building or fire inspector.  A very high percentage of self-installed stoves remains a high probability in the US, in part because of the increasingly high volumes of stoves sold through hardware chains and on-line.  The percentage of self-installed stoves purchased on the second-hand market could be even greater than the 70% figure found in 1982.  In addition to dangerous self-installation practices, the other main cause of stove-related house fires is excessive creosote build-up in chimneys that are not regularly cleaned.

 

The highest volume recalls have been pellet stoves, which pose less of a fire risk when self-installed, or from lack of chimney cleaning.

 

1. The recall impacting the most devices was the 2015 recall of the US Stove HomComfort pellet stove that could be mounted in a window or wall.  This recall involved 4,400 units, which provides one of the few insights into volumes of particular units.  The Chinese-made stove was sold at Northern Tool, Rural King, Home Depot and Lowes from 2010 to 2012.  There were 16 reports of fires and property damage, but the recall did not happen until three years after the product run.  US Stove offered $868 cash or $1,200 credit towards the purchase of another US Stove product. Those amounts are still available from US Stove.  An updated version of the stove is 2020 certified but only supposed to be mounted in walls, not windows.

 

2. The next largest recall was England Stove Works pellet Smartstove.  The US-made unit was only sold for a few months in the fall of 2015. After the company received four reports of incidents and one minor injury, it initiated recall the following year.  Englander sent consumers a free repair kit to remedy the issue.  An updated version of the stove is 2020 compliant and on the market.

 

3.The next largest recall was for 2,000 Mt. Vernon pellet stoves made in the US by Quadrafire, a subsidiary of Hearth & Home Technologies.  The $4,000 stove was sold for almost a year between 2014 and 2015.  There were eight reports of glass breaking after excessive pressure built up in the firebox but no reports of injuries.  The company remedied the issue by offering to arrange for free installation of an enhanced control board. The firm's dealers contacted known purchasers.  An updated version of the Mt. Vernon is also 2020 compliant and on the market.

 

 

4. The following year saw a much smaller recall of a Quadrafire device. This time it was a wood stove, the Explorer III, and involved 650 units.  The US-made unit was sold for about a year and a half for $3,000.  The danger was that the handle of the top lid could disengage and the lid could fall.  There were five reports of incidents, two of which involved minor injuries to fingers. The company offered to fix the problem through its dealer network. The Explorer is off the market.

 

 

 

5. A small recall of 200 Scan Andersen wood stoves made by Jotul occurred back in 2010.  A faulty door hinge led to the door falling off, and of the three reported incidents, one consumer received a bruised foot.  The stove was made in Norway and the fix was a free hinge repair.

6. Going back a bit further in time, there was a recall of 1,300 EPA certified, catalytic Vermont Castings Sequoia wood fireplaces in 2006.  At the time, Vermont Castings was owned by the CFM corporation and the units were made in Canada and the US.  They sold from 2003 to 2006 for about $2,200.  This was a more serious recall, as it involved insufficient insulation or a missing weld, and could cause these fireplaces to pose a fire hazard, though no incidents were reported.  Consumers were advised to stop using the product immediately, and it is not clear if the company offered any remedy after 2008 when they went bankrupt. 

 

 

7. The final recall listed on the CSPC database dates back to 1979, and involved glass for stove doors that posed a breaking hazard. The glass doors were in “Hearth-Glo” wood burning circulators made by the Jackes Evans Manufacturing Company. These sold in 1977 and 1978, right before the EPA began requiring wood stoves to be certified. One thousand stoves were involved and customers could get free replacement doors.

8.  While not yet a formal recall, the EPA is taking an unprecedented step of revoking the certification of a wood stove because the lab did not do the test correctly and the EPA certified the stove because it did not carefully read the lab test report.  The stove in question is the England Stove Works Model 50-T tested by Intertek, and the wood they used was too dry. It appears that Englander tried to test it again but couldn't get it under 2 grams an hour. Englander had requested a hearing, but they pulled out of the hearing process and the EPA is finalizing revocation of the model line in April 2022, which apparently will mean those models will have to be recalled from retailers.  

May 15, 2020: a historic day for wood heat technology

The end of an era for some iconic stove models and the beginning for others

Quadrafire's Mt. Vernon AE is
one of many popular, iconic stove
lines going out of production 

Ten years in the making, modern wood heater emission standards are finally here, today on May 15. Hailed by many and derided by many, May 15 brings to a close a major chapter  in the book of wood heater regulation- though not the last chapter by any means. The EPA, industry and states continue to work on cordwood test methods, parts of the Hearth, Barbecue & Patio Association (HPBA) lawsuit are still outstanding, and public comment will soon be open about a likely proposal for a fall sell-through of Step 1 stoves.

To draw an analogy from biology, today marks a mass extinction of heater models unparalleled since the 1988 – 1990 period when even more heater models died off because they could not meet basic emission standards. The largest genus of stoves to die off back then was the Fisher family of stoves, though they live on in tens if not hundreds of thousands of American homes.  A few that go extinct today are also akin to famous dinosaurs, like the Ashley circulator line of stoves, that appear to lack a 2020 compliant version for wood.  Granted, some of the most iconic stove models quietly slipped out of production years ago, like the Acclaim, Intrepid and Vigilant, which have sold more units than most current models ever will, between their catalytic and non-catalytic versions.

For pellet stoves, May 15 marks the end of the Whitfield era.  Whitfield pellet stoves are still renowned for their simplicity and durability and they lived on via the Montage model made by Lenox and then by IHP.  As of May 16, Jerry Whitfield’s legacy is alive and well in the history books but gone from showroom floors.  The Mt. Vernon AE, another classic and popular pellet stove made by Quadrafire is also gone the way of the dinosaur, (the company continues to build the slightly similar Mt. Vernon E2).

The classic Jotul F 602 endures
with a 2020 compliant version

Then there are stoves like the classic Jotul F 602 that was popular when it was introduced in the 1930s. It’s virtually identical looking modern version is 2020 compliant, and still popular. 

The millions of dedicated, experienced wood stove enthusiasts in the US may be a nostalgic lot, who fondly remember the old models and the days when emissions limits were not as strict.  But May 15, 2020 is also a milestone in stoves becoming cleaner and more efficient, a point that often seems to get lost in the acrimony about the how the EPA is managing the process.  

It’s tempting to say that the 2015 wood stove rules, that culminated today in a 2 to 2.5 gram an hour standard, will give the stove industry a new lease on life, like the 1988 EPA regulations did.  The jury is still out on how much better these stoves are than the ones allowed to emit up to 4.5 grams an hour and some models were likely brought to market too quick, before they were sufficiently field tested.  Instead of touting the new prowess of these cleaners stoves, almost all industry leaders have  been saying there is no appreciable difference between a 2-gram standard and a 4.5 standard.  Part of this is a messaging tactic to oppose stricter standards or possibly they know more about how test labs can produce ever lower emissions data from virtually the same stove.   

The sell-through that kept falling through

The May 15 deadline was a sour one for many retailers and industry members who thought that there would be a sell through.  First, the EPA raised their hopes by proposing a sell-through in 2018, only to reverse course and deny it in March 2020.  The March ruling was a blow to industry morale even though the EPA agreed to publicly tell industry in October 2019 that they should stick to the original

Senator Carper (D-DE) has emerged
as a leading voice for stricter stove
regulations in the Senate

timetable.  Then HPBA rallied again in March 2020, apparently thinking they could get a Direct Final Rule, allowing a sell-through starting on May 16, and everyone’s hopes went back up again.  And, Mandy Gunasekara was back at the EPA, after more than a year absence. But Direct Final Rules are for non-controversial changes that won’t be opposed by any stakeholder.  Senator Carper from Delaware quickly made sure that they EPA knew how contentious a sell-through was.  

It wasn’t until early May that it became clear to HPBA that getting a Direct Final Rule was like threading a needle in a hurricane, even with some high-ranking friends in the Trump Administration.  Then, HPBA seemed to quickly change course, urging industry to ignore the possible sell-through that they had fought so hard to secure.  HPBA unveiled a promising  Stoves to Homes Initiative that would allow retailers to give away their unsold Step 1 stoves to a charity who would then install them in low-income homes.   [Update: At 5:00 PM on May 15, the EPA released the details of a proposed sell-through window in the fall, ending on Nov. 30, and after public comment and an online hearing.]

HPBA worked hard on behalf of its membership on all three branches of government: Congress, the courts and the Administration.  HPBA came extremely close to victory in Congress, passing a far-reaching three year delay Bill in the House, championed by Rep. Collin Peterson (D-MN) who represents Central Boiler's district.  This was far more than a retailer sell-through and industry could not secure support from key democrats in the Senate when the initiative failed.  Many assumed industry could secure relief from the Trump Administration, as so many other industries have, and the 2018 EPA sell-through proposal was the fruit of those efforts.  Some speculate that the 2018 departure of EPA official Mandy Gunasekara left HPBA without a high-ranking benefactor to shepherd through the sell-through proposal.  It may have been left to lower

As manufacturers tried to
assure their retailers they were or
would be ready for 2020 back in
2017 and 2018 with ads like this,
the EPA saw an industry that did
not need a sell-through

level EPA staff who sided with states and air agencies that the case for a sell-through was weak.  What the EPA may have failed to grasp, was that even through many stoves were certified to 2020 standards in 2016, 2017 and 2018, many manufacturers did not make those models available to retailers until later in 2019, leaving retailers no option but to continue buying Step 1 models until the very last heating season.  

Finally, in the third branch of government, the courts, HPBA’s legal strategy seemed to unravel as it requested extension after extension and as time passed, more and more stoves were certified to the 2020 standards, including the 2.5 gram an hour cordwood standard. HPBA had a strong claim the EPA lacked sufficient data to set a cordwood standard, but then its members began favoring the looser ASTM cordwood standard.  After 5 years of advocacy, industry had little to show to the retailers, many of whom are now angry.  

Fortunately, 2018 and 2019 were mostly good years for much of the manufacturing and retail industry, according to a number of detailed articles in Hearth and Home Magazine.  The wood and pellet heater industry entered 2020 on decent footing, though many manufacturers and retailers increasingly make profits from their gas and electric lines of appliances, not wood and pellet.  Then the coronavirus hit with a broadside slam that appears to be lingering not just through the spring and summer, but potentially could have a major negative impact in the fall of 2020 and well into 2021.  The pellet stove and boiler sector is also particularly susceptible to low oil prices, which simultaneously accompanied Covid-19 in its swath of destruction through the economy.

In addition, the industry’s right-leaning, anti-regulatory tilt has built friends in Congress and the Administration, but not necessarily with the leaders of the renewable energy movement, who seem to be increasingly looking to electrify residential heat. Privately, many HPBA members say they wish the association had not tried to fight the regulations so hard, even though the outdoor boiler and warm air furnace sectors were pushing them to do just that.  If Senator Biden is elected in November, industry would likely do well to try to quickly reposition themselves and be part of coalitions that could stand to benefit from a pro-renewable administration.  Pellet heating technologies should be best positioned to benefit from some form of green new deal and potentially help end the difficult, cyclical boom-bust nature of pellet heater sales.

Certified stoves on May 16

 

A screen shot of the EPA database on
May 15, showing 610 certified stoves.

The number of stoves on the EPA’s list certified room heaters is about to plummet downward, from 610 to 211 stove models.  Hundreds of models that design firms, engineers, lab technicians, production line workers brought to market, will be things of the past.  They represent millions upon millions of stoves that families gathered around in the evening, that kept them warm during power outages, and helped them save enough money for groceries and other essentials.  My grandparents, my parents and my family used many of those stoves, considered to be the best technology of their era.  One of them, a pellet stove made in 2014 and has worked beautifully since then, heats my home as a I write this.

So we put our faith again into the hands of the engineers and lab techs to come up with even better stoves, that will be even cleaner and more efficient. We won’t see the huge PM reduction and efficiency gains that we experienced in 1988- 1990, but chopping lab numbers in half, from 4.5 to 2 or 2.5 grams is no easy feat and should be embraced by all of us.  We should applaud the engineers who do this for us, and especially those who are working not just to achieve these numbers in a lab but who are trying to ensure stoves are cleaner in our living rooms.  

Both wood stoves up for
awards at the HPBA 2020
Expo were automated, a
sign that the stove industry
is movig forward.

Reducing average stove emissions by a gram or two or three per hour from a stove is a major achievement that will protect the lungs of not just those that buy stoves, but their kids, their parents, their grandparents – and their neighbors.  Granted it will take decades for these cleaner and more efficient stoves to be commonplace in homes across America.  After all, there are still millions of uncertified, pre-1988 stoves in homes.  

But we should not forget that the drop to 4.5 grams an hour actually happened more when Washington State changed their standards in 1995, than it did in 2015 when the EPA adopted that change.  Those two decades of sales of cleaner stoves all across America were a blessing that has had long-term ramifications.  Two decades from now, I hope we will be able to look back and appreciate the engineers who designed these cleaner 2020 appliances and gave a new lease on life to this vital renewable energy technology.

Despite claims of "devastating" impact, wood stove industry positioned to meet new emission standards

With the Step 2 deadline for wood and pellet stoves just a year away, most stove manufacturers say they are ready or will be soon. Many retailers also say they are ready, while others prepare to deeply discount stoves that can't be sold after May 2020. Gone are the days when industry was trying to convince Congress and the Administration that EPA's new stove regulations would have a "devastating" impact. Such claims are common in Washington, as groups try to rally their base, but it can also lead to a diminished credibility for an industry association if the hyperbole goes too far.

From the start, it was clear that the boiler and furnace manufacturers needed relief far more than stove companies and retailers.  Heads of outdoor boiler companies and indoor wood boilers that cost less than the average wood stove were leaders of a campaign to get Congress to give all classes of heaters a three-year delay in meeting the new standards.  At the same time, the industry association Hearth, Patio & Barbecue Association (HPBA) was challenging many of these standards in court, meaning a three-year delay could be permanent for some classes of heaters, if courts agreed with HPBA.  But it was never clear that stoves needed any delay and industry effort would have stalled innovation and efficiency improvements and put tens of thousands of families at higher risk of more wood smoke exposure.  The fallback position was that industry needed a two-year sell year, allowing manufacturers to sell Step 1 product during the fall and spring of 2019/2020, and retailers to sell Step 1 product until May 2022.  

At first, it appeared that the EPA under the current Administration was open to providing a two year  sell-through for stoves, but they have only issued a Notice of Proposed Rulemaking (NPRM) for boilers and furnaces, not for stoves.  Theoretically, the EPA could still issue a Notice of Proposed Rulemaking for a sell through for stoves but at this point it may be too late to provide any meaningful relief.

Many states pushed back strongly against watering down the NSPS and no state filed comments backing the Trump Administration's proposals.  States also began preparing their own plans in the event the EPA does change NSPS timelines, which could create a patchwork of regulations and more antagonistic relationships with a renewable energy industry.

If some manufacturers were not taking the 2020 deadline sufficiently seriously from 2016 - 2018, they are all likely to be doing so now.  Instead of focusing on government relief, HPBA's outreach to industry stakeholders is taking an a more urgent tone that everyone needs to focus on heeding the May 2020 deadline. However, almost all manufacturers were already focused on May 2020 for their own financial health and to assure their retailers that they are a reliable future partner.  And, many manufacturers and virtually all retailers already are well-diversified with gas fireplaces and stoves which often outsell their wood and pellet appliances.

The list of stove manufacturers who are ready for 2020, almost are or “well-positioned” to be 2020 ready grows by the week. As of May 1, they include:  APR Industries, Blaze King, Even Temp, ExtraFlame, Foyers, Heat Tech, Hearthstone, Innovative Hearth Products, Jotul, Kuma, Laminoux, MF Fire, Napoleon, Pacific Energy, Rais, Regency, Roby, RSF Fireplaces, SBI, Stuv, Supreme, Thelin, Travis and Woodstock Soapstone.  Hearth & Home Technologies, by far the largest manufacturer, says a majority of its stoves will be 2020 certified this year.

The 2020 deadline will undoubtedly be tough for much of the industry, but it remains to be seen if it’s tougher than lean shipment years such as 2007 and 2012.  Overall, the threat to industry does not appear to be as serious as industry claimed even a year ago.  The 2020 deadline is also bringing about benefits. some foreseen and others not. Some retailers still have stocks of Step 1 stoves and there is likely to be some heavily discounted stoves in the final year leading up to the deadline.  Retailers are still ordering some Step 1 stoves, but in much smaller quantities.  Many retailers are only buying Step 2 stoves but may face still competition from fire sales of Step 1 stoves by competitors.  Sending Step 1 stoves to Canada could have been a good outlet, but the more populous Canadian provinces have either adopted the 2020 deadline or are in the process of doing so. Other foreign countries are still a good option.  Most big box stores have the buying power to protect themselves by requiring manufacturers to buy back unsold inventory, influence that specialty hearth retailers don't have. 

Over the last six months, HPBA has developed more clear and insistent messaging for retailers and is using social media more to get the message across.  A facebook post outlined 5 things retailers need to know to survive the NSPS. Included is also a fear that in the race to meet the 2 gram an hour standard, some manufacturers may be putting out stoves that haven't been sufficiently beta-tested and simply won't work well in the real world.  This could jeopardize retailers who unknowingly carry those stoves.  HBPA urged retailers to test the stoves themselves, before selling them to customers, a tall order for retailers over the summer season.  The message for consumers is that the next twelve months will be a buyers’ market with unprecedented sales and discounts of Step 1 products

For the most part, the hyperbole from industry that consumers would be priced out of new stoves and there would be very little variety of product on floors, is not materializing.  Some manufacturers that were well known for disparaging catalytic stoves are now embracing them, swelling the ranks of "hybrid" stoves that only mention the catalyst in the fine-print. Presumably, this new crop of hybrids learned the tough lessons of the 80s and 90s, and their catalyst are well protected from flame impingement.

The 2020 deadline is also providing industry a gradual transition to cordwood testing, as some manufacturers opt to test with it.  Some groups idealistically hoped for a far quicker transition to cordwood.  Stoves tested with cordwood can emit up to 2.5 grams an hour, although many of them are coming in under 2 grams.  Despite messaging in advertisements from HPBA that it "shares the same goals as regulators," the 2.5 gram an hour standard for cordwood is one of the many emission standards that HPBA is challenging in federal court.  The many delays to the lawsuit may make it tougher for HPBA if enough stove models come in under 2.5 grams an hour using the broadly applicable alternative ASTM cordwood test method.

Many stakeholders are already looking past the 2020 deadlines toward the next NSPS, which by law should be scheduled in 2023.  Whenever the 2015 NSPS is superseded, there is likely to be intense controversies over certification protocols for cordwood testing and a timeline for all stoves to be tested with cordwood.  Key northeastern states believe the consensus driven ASTM Method is deeply flawed and are working behind the scenes on new test methods.

Unlike the 1988 wood heater NSPS that decimated the ranks of small stove manufacturers, the 2015 NSPS does not appear to be forcing manufacturers out of business. The 1988 regulations drastically improved the functioning, safety, cleanliness and efficiency of stoves while also driving up prices of those that were not claimed to be exempt.  The question remains whether the 2015 NSPS will significantly improve the functionality of stoves as they become cleaner and more efficient in the lab. Pellet stoves may the winners as their lab numbers should hold up in homes of consumers, a significant benefit that is rarely acknowledged by most in industry.  We can all agree that there will be both intended and unintended consequences which will take years to unfold.  Stay tuned.

March 11, 2020 update: The EPA finalized amendments to the 2015 NSPS and did not provide a retailer sell-through.  They did remove pellet fuel minimum requirements but retained the list of prohibited fuels in the 2015 NSPS.

  

Nearly 20% of stoves meet new emission standards; wood boilers lag behind

By John Ackerly and Melissa Bollman, Alliance for Green Heat

Of the 518 wood and pellet stoves currently on the market in the US, 91 or about 18% are certified to the stricter emission standards that are set to take effect on May 15, 2020. In general, smaller companies with fewer models tend to be more prepared for the 2020 deadline than larger companies with many models. Pellet stoves can meet the 2020 emission standards relatively easily, and some companies that make only pellet stoves have fully 2020 compliant product lines. [Update: as of May 2019, 25% of stove models are 2020 certified and now can be easily viewed on the EPA's new searchable database of certified stoves.]

While more and more wood and pellet stoves are meeting the new emission standards, American wood boiler companies are still struggling to make boilers clean enough to be certified to 2020 standards. The wood heater industry appears to be waging legislative and legal battles that will benefit the outdoor wood boiler industry the most. For the wood stove manufacturing community, a sell-through for retailers appears to be the most important type of relief. The Alliance for Green Heat supports no more than a one-year sell-through for wood heater retailers.

Meanwhile, Senators are preparing an amendment or bill that would provide $75 million a year for 6 years for a national change-out program fund, a staggering amount of money that could spur sales of 2020 compliant stoves. The bill also contains a one-year sell-through provision for retailers. Industry is not supporting this amendment as of now, opting for a bill with 3 year delay of NSPS deadlines without any funding for change outs.

One dilemma underlying the transition to stricter standards is that manufacturers are still recertifying virtually all of their stoves with cribwood, not cordwood. Thus, the opportunity to shift toward stricter emission standards with the fuel homeowners use—cordwood—was not achieved with the 2015 NSPS. Even if industry succeeds in getting a 3-year delay for the standards, it is not at all certain that manufacturers will opt to test to cordwood standards. Until one or more states or incentive programs require stoves to be certified with cordwood, there may be little incentive for manufacturers to test with a cordwood protocol.

Stove compliance trends

The latest list of EPA certified stoves reveals that about 13% of stove companies have fully 2020 compliant product lines. (This figure includes only stove manufacturers that produce at least two EPA certified models.) Most company product lines are between 5% and 30% 2020 compliant, but several popular companies, including Jotul, Kuma, and Napoleon (Wolf Steel), do not currently have any stoves listed on the EPA list that meet the Step 2 emissions standards. Wood heat retailers currently do not have a sell-through period to sell their existing stock once the Step 2 emission standards take effect in May 2020, but the EPA recently proposed changes to the NSPS that are likely to give retailers a sell-through period.

How to read this chart (click to enlarge): This chart shows the number of 2020 compliant wood and pellet stove models produced by large manufacturers (manufacturers that produce at least eleven EPA certified models) as bars on the primary (left) y-axis and the percentage of models the manufacturers produce that are 2020 compliant as a point on the secondary (right) y-axis.

Several smaller pellet stove manufacturers’ product lines are entirely 2020 compliant. The chart below shows the number of 2020 compliant models produced by smaller stove manufacturers (manufacturers are considered small if they produce between 2 and 10 certified stoves on the EPA list; manufacturers with only one EPA certified wood or pellet stove in production are not included.)

Furnace and boiler compliance trends 

The wood and pellet boiler and furnace industries appear to be exhibiting similar patterns. Only ten (9%) boiler models (eight cordwood and two pellet) and one forced-air furnace, a cordwood model by Lamppa, are certified as 2020 compliant, according to the EPA lists which were last updated in June.

Some boiler and furnace manufacturers are planning to stop manufacturing boilers or leading an aggressive campaign not only to delay the 2020 standards but also to significantly weaken emission standards for outdoor and indoor wood boilers.

How to read this chart (click to enlarge): This chart shows the number of 2020 compliant models produced by hydronic heater manufacturers. It includes both the number of 2020 compliant models listed on the EPA list and the number of models that emit under 0.10 lb/mmBtu (crib wood or pellets) or under 0.15 lb/mmBtu  (cord wood) but need to be retested before they are 2020 compliant. This chart only includes boiler manufacturers that produce at least three certified models on the most recent EPA list.