We investigated two issues, of which one was resolved informally.

Ad description

Pages on the website for Stovax,, for wood burning stoves, seen in January 2019:

A product listing for “Freestanding Elise 540 Wood Burning & Multi-fuel stoves” included the text “They are equipped with ultra-green combustion technology keeping emissions exceptionally low and making these models compliant with future Ecodesign standards”. Under the heading “FEATURES”, the listing included eight logos including “SIA eco-design ready” and “Eco design compliant”. One of the logos was a green roundel with a picture of a flame and the text “CLEANBURN TECHNOLOGY”. The page included a list under the heading “KEY FACTS” that stated “Ecodesign compliant”. Further down the page under the heading “FREESTANDING ELISE” text included “The Freestanding Elise wood burning and multi-fuel range meet the Ecodesign standards of tomorrow, Stovax’s cleanest burning range of fires”. Clicking on the “CLEANBURN TECHNOLOGY” roundel took website visitors to a page titled “Ecodesign Ready Stoves & Fires”. The page “Ecodesign Ready Stoves & Fires” explained that Ecodesign stoves and fires were products designed to comply with the government’s Clean Air Strategy and what effect that would have on the product. The page was headed with text stating “BURN CLEAN STANDING BEHIND THE GOVERNMENT’S CLEAN AIR STRATEGY”. Further down the page, the ad stated “Designed for our Environment … Ecodesign Ready stoves represent the future of wood burning. Supporting the Government’s Clean Air Strategy, these advanced stoves burn so cleanly, and in many cases even exceed, 2022 air quality and efficiency targets”.


The complainant, who understood that wood burning stoves produced fine dust pollution, challenged whether the claims “CLEANBURN” and “BURN CLEAN” were misleading and could be substantiated.


Stovax said that ‘clean burn’ and variants of that claim had been used in the industry for years by the majority of manufacturers and governing trade bodies. The industry consensus was that those terms were well understood by consumers. Stovax stated that ‘clean Burn’ products were differentiated from less efficient products; the term referred to a technological difference in appliances that gave them higher efficiency combustion and reduced emission smoke particles. Clean burn stoves and fires were approved for Department of Environment, Food and Rural Affairs (Defra) Smoke Control Areas (areas where the only exit smoke allowed from chimneys was from authorised fuels and exempt appliances) under the Clean Air Act 1993 and produced 90% fewer particulates than an open fire and 80% fewer than designs that did not use that technology.

The Stove Industry Alliance (SIA), a trade association for stove and fireplace manufacturers, also provided a response to the ASA. The SIA said that ’clean burn’ was not intended to be an absolute statement and they did not consider that consumers would be misled by it. They stated that in the context of reduced emissions, the term ’clean’ was used by the government in the Clean Air Act, the Clean Air Strategy published by Defra and the Clean Growth Strategy by the Department for Business, Energy & Industrial Strategy (BEIS). In all those cases, ’clean’ air did not mean air without any emissions, but air with only a permitted proportion of emissions. The SIA said that there were lots of publically available resources that made clear the meaning of clean burn’ including Stovax’s own website which contained a definition. They further considered that it was important that consumers could distinguish between products that did and did not meet the requirements of the Clean Air Act and that were furthering the objectives of the Clean Air Strategy.


Not upheld

The ASA considered that consumers would understand the claim “clean burn” in the context of the product listing, which included prominent claims that the product included “ultra-green” technology that would result in “lower emissions” and that it was “ecodesign compliant”. The claim “clean burn” appeared in a roundel that was part-way down the web page and relatively small. The claim was presented as a logo and we therefore considered that consumers would understand from the claim and its presentation on the page that clean burn referred to a standard that meant that the product produced lower emissions than products which did not have that logo. Clicking on the roundel that included the claim took website visitors to a web page which included an explanation of the term clean burn. The page explained that stoves that were manufactured to comply with the regulations set out in the Clean Air Act contained clean-burn technology. The page further provided a detailed explanation of the meaning of the term, how stoves with clean-burn technology worked and what that would mean for consumers. We considered that adequately explained the term and the manner in which it was applied. We understood that the stoves complied with the standard required to be referred to as containing clean-burn technology (i.e. a major reduction in emissions compared to models that did not contain that technology).

We therefore concluded that the ad was not misleading. We investigated the ad under CAP Code (Edition 12) rules 3.1 (Misleading advertising), 3.7 (Substantiation) and 11.1, 11.2 and 11.3 (Environmental claims), but did not find it in breach.


No further action necessary.

CAP Code (Edition 12)

3.1     3.3     3.7     11.1     11.2     11.3     11.4    

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