Cardiff Engineer’s Pellet Stove Aims to Cut Indoor Wood Smoke 2026

Key Points

• Engineer Marc Howell of Cardiff has come up with a wood-burning stove patent which can reduce any risk of indoor pollution caused by wood-burning.
• This technology has been developed by Island Pellet Stoves Ltd., a manufacturing company located in Wales, Cardiff.
• The system has taken Howell seven years to develop it in a garage close to Cowbridge, Vale of Glamorgan.
• The stove uses wood pellets produced from sawdust, which is a product of the timber industry rather than logs.
• The wood burner does not need to be opened for lighting and feeding of pellets since these processes are automated with the help of an Archimedes screw controlled by a computer.
• Balanced flue system pre-heats the combustion air with the help of exhaust gases.
• According to a DEFRA commissioned report called Emission Factors for Domestic Solid Fuels released in February 2025, the pellet stoves from Island Pellet Stoves were about 20 times cleaner than a log burner in terms of particulate emissions.
• The company claims its stoves are DEFRA-approved and HETAS Cleaner Choice Certified.

Cardiff (Wales Times) October 28, 2026 – A Welsh engineer has developed a domestic wood-burning stove that its manufacturer says can provide the experience of a real fire while reducing the risk of harmful pollutants entering the home. The invention, created by Marc Howell and manufactured by uk/local/cardiff/">Cardiff-based Island Pellet Stoves Ltd, uses automatically controlled wood pellets and a sealed balanced-flue system to limit indoor pollution.

As reported by Nation Cymru staff, Howell studied engineering at Cardiff University before working in the automotive and semiconductor industries. He then spent seven years developing the patented technology in a garage near Cowbridge, in the Vale of Glamorgan.

The company, Island Pellet Stoves Ltd, describes itself as the United Kingdom’s market leader in pellet stoves and says it designs and manufactures its appliances in Wales.

How does the Welsh pellet stove work?

The system is built around wood pellets rather than traditional logs. According to Nation Cymru, the pellets are manufactured from sawdust produced by the timber industry and formed into dry, regular-shaped pellets containing less than 1% ash and less than 10% water.

Howell said the aim was to make wood burning cleaner without removing the qualities that make a stove appealing. As reported by Nation Cymru, he stated: “Burning wood just had to be made more efficient and less polluting.” He added that experience gained from reducing emissions in larger-scale wood pellet systems showed there was a way to create “the real wood fire experience that is so desirable in the UK” while avoiding harm to health.

The stove is computer-controlled. It automatically lights the pellets and regulates their supply from an on-board storage hopper to a burn-pot using a computer-controlled Archimedes screw. Nation Cymru reported that this removes the need to open the stove door during operation, unlike a conventional log-burning stove.

Because the door does not need to be opened to add fuel, the company says the risk of pollutants entering the living space is eliminated.

The appliance also uses a balanced flue, a system commonly associated with domestic gas boilers. Exhaust gases pre-heat the incoming air to a high temperature before it is used for combustion. According to Nation Cymru, this allows more precise control of the burning process, reduces emissions and increases the efficiency with which energy is extracted from the pellet fuel.

What does the DEFRA testing show?

A report commissioned by the Department for Environment, Food and Rural Affairs (DEFRA) and published in February 2025, titled Emission Factors for Domestic Solid Fuels, tested the company’s pellet stoves. As reported by Nation Cymru, the testing found that stoves made by Island Pellet Stoves Ltd were around 20 times cleaner than a modern log burner for particulate emissions.

The company’s own materials provide further detail on the tested Ramsey model. Island Pellet Stoves said the Ramsey reduced particulate matter, specifically PM2.5, by 95% compared with a standard log burner. It said official 2025 tests recorded emissions of 0.3 grammes of dust per hour, making the stove “20 times cleaner” than an Ecodesign log burner.

The company also says its stoves are DEFRA-approved, meaning they comply with the Clean Air Act, and HETAS Cleaner Choice certified. HETAS describes Cleaner Choice as an independent review of test data intended to verify that a technology significantly reduces particulate matter emissions.

Separately, Build It quoted Howell explaining that a Leeds University study found wood pellet stoves were up to 30 times cleaner than traditional log-fuelled woodburning stoves. The same article stated that Island Pellet Stoves’ Lundy model could achieve a 98% reduction in particulate and nitrogen oxide emissions compared with a traditional multi-fuel stove.

Can pellet stoves eliminate pollution completely?

The central claim in the original Nation Cymru feature was that the invention could “eliminate indoor pollution” from wood-burning stoves. However, a later Nation Cymru report added important context to that claim.

That report stated: “No wood-burning or pellet stove can fully eliminate emissions.” It explained that even sealed systems can still produce bursts of pollutants during ignition, refuelling, ash removal or through small leaks.

The later report also clarified that the approximately 20-times-cleaner figure is based on certain laboratory testing conditions. It said the DEFRA and Ricardo report confirms that pellet stoves have much lower particulate emissions than log stoves, but does not claim zero emissions.

This distinction matters for readers assessing the technology. The available evidence indicates a substantial reduction in particulate emissions compared with modern log burners, rather than evidence that the appliance produces no pollution at all.

Why does indoor air pollution matter?

Wood smoke contains particulate matter, small particles that can enter the air inside and outside a home. Traditional log stoves can release smoke when fuel is added, particularly if the stove door is opened during operation.

In the Build It article, Howell said research had suggested that up to 70% of wood smoke emitted by a traditional log stove could re-enter the home, affecting indoor air quality.

The Midlands Gazette, in a separate report on the company, said traditional log-burning stoves were under scrutiny because of the particulate emissions they produce. It reported that Island Pellet Stoves burn pellets made from sawdust, a waste product of the timber industry, and said these pellets produce “virtually no ash or smoke” when burned because they contain no bark.

The company says pellet stoves use temperature control to regulate heat output. According to the Midlands Gazette, the computer slows or stops the flow of pellets once the desired temperature is reached. It further reported that Island Pellet Stoves use, on average, between one third and one half as much fuel as a log burner because of this controlled operation.

Who developed the stove?

Marc Howell is identified by Nation Cymru as the founder of Island Pellet Stoves. He studied engineering at Cardiff University and later worked as an engineer in the automotive and semiconductor sectors.

The company’s website identifies Howell and Dr Gabriel Gallagher as professional engineers and founders who have worked in sustainability and commercial wood energy since the 1990s.

The Midlands Gazette reported that both Howell and Gallagher attended Cardiff University and described the stoves as the work of “two engineering friends”. It said the company designs and builds its own British version of pellet stoves, rather than importing them.

According to the Midlands Gazette, parts are sourced and precision-manufactured in the United Kingdom where possible, including carcasses made from British steel. Final construction is said to be carried out by hand at the company’s factory in Cardiff.

Where can the stoves be used?

The balanced-flue design may broaden where the appliance can be installed. The Midlands Gazette reported that the patented flue controls the outflow of fumes and the inflow of air, allowing installation in properties with or without a chimney, including conservatories, boats and yurts.

The company says its stoves can be operated using a handheld remote or wall-mounted thermostat. It says the system automatically ignites the pellets and controls their feed from a hopper, using precise levels of pre-heated air.

For households in Smoke Control Areas, the company says its pellet stoves are DEFRA-exempt and can be used with 6mm diameter, approximately 20mm-long EN-Plus wood pellet fuel.

DEFRA approval is significant because, in Smoke Control Areas, the law permits only authorised fuels or DEFRA-exempt appliances. The company says its Lundy stoves have passed emissions testing and have been declared exempt in England, Wales and Scotland.

What happens next for wood-burning homes?

The development arrives as solid-fuel heating faces increasing regulatory and public-health attention. The Midlands Gazette reported that the government had announced proposals to cut smoke-emission limits and require log-burning stoves to carry a health warning stating that the appliance emits air pollution into and around the home which can harm health.

The same report said log burners installed before 2018 could be affected by the proposals, meaning some owners may need to reconsider their heating source.

Island Pellet Stoves says pellet stoves and compliant modern solid-fuel appliances are not being banned in the UK. It notes that since January 2022, new regulations have required wood burners and similar stoves to meet Ecodesign emissions standards before sale.

Background of the development

The invention emerged from Howell’s attempt to reconcile two issues: the continued appeal of wood-fired home heating and concerns about the air-quality impact of burning solid fuel. Nation Cymru reported that he could see both the benefits of sustainably heating a home with wood and the potential conflict with health effects caused by air pollution.

Wood pellets were central to the solution. Because they are dry, uniform and low in ash, they can be fed and burned in a controlled way, unlike logs, which vary in size, moisture content and burning behaviour.

The company’s technology combines automated pellet feeding, computer-controlled combustion air, a sealed operating system and a balanced flue. Together, these features are intended to reduce emissions and prevent smoke from escaping into the room when fuel is added.

The DEFRA-commissioned Emission Factors for Domestic Solid Fuels report, published in February 2025, provided independent testing context for the company’s claims. Nation Cymru reported that the testing found Island Pellet Stoves’ appliances were around 20 times cleaner than a modern log burner for particulate emissions.

Prediction: How could this affect homeowners?

For homeowners who use wood-burning stoves, the development could make pellet heating a more practical option where indoor air quality, fuel efficiency and Smoke Control Area rules are concerns. The sealed, automated design addresses one of the main sources of indoor exposure associated with log stoves: opening the door to add fuel.

For households in towns and cities covered by Smoke Control Areas, DEFRA-exempt pellet stoves may offer a route to continued solid-fuel heating within existing legal rules. The company says its stoves are DEFRA-approved and suitable for use in such areas.

For people considering a new stove, the evidence suggests pellet appliances may produce substantially fewer particulates than modern log burners, although they do not remove emissions entirely. Buyers would still need to consider installation requirements, fuel availability, running costs and the need for correct maintenance.

If stricter emission rules proceed as reported, demand may shift further towards lower-emission appliances. For owners of older log burners, particularly those installed before 2018, the development could become relevant if future policy encourages replacement or tighter controls on solid-fuel heating.