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.

Meet the Contestants; HWAM

With the first Wood Stove Decathlon only a few months away, we here at the Alliance for Green Heat have started a weekly blog to showcase the Decathlon competitors. Take this opportunity to learn more about the design teams and their stove’s innovative features.

One of the European finalists of the Decathlon is the newly developed HWAM 3630 IHS from the Danish manufacturer HWAM. The stove is run by an oxygen sensor and computer, and even beeps when it’s the optimal time to reload more wood. This is one of the finalists that is already on the market and retails for $4,216.

HWAM has had a longstanding ambition to develop a more intelligent stove to heighten the technological level of its products. Helping the consumer burn wood with minimal attention to the stove and no experience necessary, while achieving the same results at home that are obtained in test labs under ideal conditions are key to their innovation philosophy.

HWAM founder Vagn Hvam Pedersen is the leading creative and technical mind behind the stove. He has outfitted the stove with advanced technology and a sleek, modern European design. For the Hvam Pederson family the stove is the center point of the home for the family to gather in comfort and warmth. Hvam Pedersen built the family owned business from the ground up until it ignited to become an internationally renowned company.

Video of HWAM
IHS features

The innovation behind the HWAM 3630 IHS rests in the Autopilot Intelligent Heat System (IHS). This system allows for precise control over the stove’s combustion and temperature. The system uses a lambda oxygen sensor and a thermocouple to electronically measure combustion conditions. These measurements are then sent to a computer that automatically regulates three independent fans to control airflow for optimum combustion. The temperature of the fire may also be controlled through a remote control, as the fans adjust their speed accordingly.

The advantage for the consumer to have IHS is that an optimum burn means the most efficient use of firewood. This puts less of a strain on the stove owner’s fuel and the environment. The concept of the stove is to work around a potentially inexperienced owner to offset human error when possible. HWAM has even been awarded the Nordic Ecolabel after following strict environmental regulations. The stove must comply with rigorous limits on local air pollution and emissions of dangerous substances such as carbon monoxide and hydrocarbons.

We are looking forward to seeing the HWAM 3630 IHS in action at the Wood Stove Decathlon November 16-19, 2013. Vote for your favorite stove at Popular Mechanics.

“Hello, iStove”: How much can lambda sensor technology improve burning efficiency?

Lambda sensor system (Reprinted from Widmann-Heizungen.it)

The introduction of innovative emissions control technology revolutionized the automobile industry, making cars safer, greener, and more efficient. Now, some boiler manufacturers are saying goodbye to the clunky, soot-filled burners of the past, and are integrating the same lambda sensor devices used in automobile engines into new state-of-the-art clean-burning wood boiler. Economical and carbon-neutral, these eco-friendly lambda heaters could help make wood-burning cool again. Goodbye low efficiency – Hello, iStove.

What is a lambda sensor?
A lambda sensor is a small electronic device that measures how much oxygen is in a gas or liquid. Lambda sensors have been used in a variety of applications since their development in the 1960s – from monitoring breathing in scuba diving to measuring soil oxygen content – but they are most well-known for their use in car emissions control technology. Lambda sensors help cars optimize the fuel combustion process, allowing engines to work as efficiently as possible with the least emissions. In lambda wood heaters, the sensors are used in a similar way to reduce fuel waste and minimize emissions during burning.

How does lambda sensor control work? 
Lambda sensors are key components in the feedback control systems that regulate combustion. Like car engines, wood stoves burn fuel (biomass) in the presence of oxygen. The ratio of air to biomass fuel (“air-to-fuel ratio”) in the stove’s combustion chamber determines how efficient the burning will be. If there is too much air in the chamber, burning will produce high levels of noxious nitrous oxide pollutants. If there is too little air, combustion will be incomplete and the stove will release wasted fuel in the form of hydrocarbon particulates and harmful carbon monoxide gas.

Feedback control fine-tunes the combustion process by varying the air-to-fuel ratio in the chamber so that burning is optimized. A lambda sensor measures the oxygen concentration of the exhaust stream leaving the stove (a measure of how much excess air is in the combustion chamber) and sends the information to a controller or micro-processor, usually as a voltage signal. The controller calculates the current air-to-fuel ratio and varies the amount of air fed into the chamber based on the real-time data from the sensor. These two components working together keep the stove running continuously at near-optimum efficiency, regardless of the species and moisture content of the fuel wood or the boiler temperature.

Lambda boiler manufacturers
Lambda boilers have been on the market since the 1980s, but in recent years more companies are focusing on the residential market and have released newer models featuring upgraded technology and a cleaner aesthetic, including British manufacturers Pevex and Attack, Swedish manufacturer Effecta, and Austria’s Fröling (Effecta and Fröling also distribute to the US). These boilers all boast improved designs and smokeless operation, with running efficiencies often over 90% LHV (normal wood stoves have efficiencies ranging from 60-90%). If lambda control is turned off or is defective, the boilers operate as conventional boilers without the increased efficiency. Prices for the boilers can average about 20% more than non-lambda boilers, typically ranging from $8,000 to $14,000, but often more, depending on model, market and desired energy output. To our knowledge, no wood stove is yet using a Lambda sensor, but it is likely just a matter of time until we see these higher efficiency stoves on the market.