The case against comparing Ecodesign stoves to cigarette smoke
Midtherm Response: Clarifying the Conversation Around Wood-Burning, Health & Technology.
At Midtherm, we welcome rigorous scientific inquiry into air quality and health. As a UK manufacturer of flue and chimney systems and a member of the SIA, we stand alongside stove makers, retailers and installers in promoting safe, efficient, and low-emission wood burning. But we must also ensure the public hears a balanced view — comparisons of modern Ecodesign stoves with cigarette smoke are misleading and risk undermining progress made in emissions reduction.
Key Points We Support & Emphasise:
1. Not all wood burning is equal. The UCL study, as reported in the media, grouped “solid fuel use” broadly without distinguishing open fires, outdated stoves, or modern Ecodesign-compliant appliances. That means it cannot credibly attribute health harms to today’s stoves, especially those installed and used properly.
2. Modern sealed stoves minimise indoor exposure. Ecodesign stoves are designed and tested to operate under negative pressure, drawing combustion air in and expelling smoke up the flue, not into the living space. When installed, used, and maintained correctly, indoor emissions are minimal.
3. Independent testing shows real gains. Compared to open fires, Ecodesign stoves can reduce particle emissions dramatically — by as much as 80–90% in some tests. (This aligns with what the SIA has stated.) As a flue systems manufacturer, we also emphasise that the integrity of the flue and chimney plays a crucial role in ensuring that performance is translated into safe operation in the home.
4. Current regulation already raises the bar. Since 2022, all new stoves sold in the UK must meet Ecodesign standards. This change effectively rules out many of the older, high-emission devices that may have been in use when health concerns were historically worse. Using correctly seasoned or Ready to Burn certified wood logs, proper stove sizing, installation to appropriate standards, regular maintenance and chimney sweeping are essential to keep emissions low.
5. The health literature is nuanced. A 2022 review by Dr Amanda Lea-Langton at Manchester University found no scientific evidence of adverse health impacts from indoor air exposures typically associated with modern enclosed stoves. Such reviews remind us that comparisons to cigarettes are not supported by the evidence when applied to modern, well-operated appliances.
This study doesn’t distinguish open fires or old stoves from modern Ecodesign models, which deliver dramatically lower emissions. Research from Manchester University found no evidence of health harm from the indoor air exposures linked to modern stoves. Comparing them to cigarette smoke is misleading — and ignores the major improvements in stove technology, flue systems, and standards.
Call to Action & Tips for Consumers (in line with best practice):
- Choose an Ecodesign-compliant stove (e.g. clearSkies certified), and upgrade if you currently use an open fire or very old stove.
- Ensure the stove is installed by a qualified competent person (HETAS, OFTEC, or equivalent) with correctly sized, certified flue and chimney components.
- Use high quality, low-moisture fuel (Ready to Burn, < 20% moisture), avoid burning waste or treated wood.
- Keep the stove and chimney clean and serviced — annual sweeping is essential.
- For homes in Smoke Control Areas, use DEFRA-exempt certified appliances.
- Most importantly: use your stove properly — follow manufacturer guidelines, avoid slumbering operation, and manage air intake controls sensibly
See the full report from the SIA published here:
https://stoveindustryassociation.org/wood-burning-stoves-cigarette-smoke-misleading/
