There are more than 1.25 million stoves in the UK, with around 200,000 stoves sold annually. As Ian Sams of Specflue points out, there are many good reasons for their popularity, not least their environmental performance.
Wood-burners are a stylish addition to any home. They can generate more heat than traditional open fires, and still provide an attractive focal point for a room.
Their appeal does not end with aesthetics, however. They are made even more attractive to homebuyers by an environmental performance that has come on leaps and bounds in recent years.
Ecodesign Directive
By no means an unsupported assertion, the environmental performance of wood-burners is backed by decisive action from the industry. The European Commission has formulated a measure called the Ecodesign Directive to reduce energy and resource consumption.
The Directive helps eliminate the lowest performing products on the market, as well as supporting industrial competitiveness and innovation by promoting better product environmental performance throughout Europe. Ecodesign for wood burning and multi fuel stoves covers a wide range of emissions from particulate matter to carbon dioxide, nitrogen oxides, other carbon gases compounds and carbon monoxide.
Though the directive is not due to come into force until 2022, many members of the Stove Industry Alliance (SIA) have decided to start releasing stoves that will meet the lower emission limits now, four years early. And, from 2020, these manufacturers say they will only produce new fireboxes that satisfy Ecodesign.
The SIA launched its ‘Ecodesign Ready’ brand in Westminster with strong Government support. The Alliance had previously tested an open fire, a stove manufactured 10 years ago and a current Ecodesign-compliant stove. This revealed an energy efficiency performance of G for the open fire, B for the 10-year old stove and A+ for the modern appliance.
So, in terms of the emissions, the open fire falls short of Ecodesign requirements, some of the stoves of 10 years ago would fail to meet the Ecodesign standard, but the modern stove was found to be compliant.
The SIA’s ‘Ecodesign Ready’ scheme is overseen by HETAS, the official body that approves biomass and solid fuel domestic heating appliances, fuels and services.
This organisation ensures that the stoves have been independently verified and that they pass appropriate tests and meet emissions and minimum efficiency criteria.
To qualify for the Ecodesign Ready label, a stove must, according to the SIA, have been independently tested by an approved test laboratory and met the emissions and minimum efficiency criteria for Ecodesign. The test results must be verified by HETAS, and the stove will then be listed on the HETAS website. The stoves will also appear in the HETAS Guide with the Ecodesign Ready label, and on its website.
Since the 1st of January 2018, all stoves displayed in a retailer’s showroom have had to show an Ecolabel, familiar as the A to G scale of energy performance already applied to white goods such as fridges, freezers and washing machines. Manufacturers must also include a printed label in the stove packaging, with information in the instructions or on a specification sheet.
Brexit will make no difference to the UK’s response to Ecodesign and Energy Labelling Directives because the Department for Environment, Food & Rural Affairs – which was involved in shaping them – has already confirmed its intention to bring them into UK law through the Great Repeal Bill.
Fuel Matters
Efficiency doesn’t depend solely on the quality of the appliance, or how the wood is burned, however. The fuel itself also has a strong bearing on performance.
Freshly cut wood has moisture content of 60 to 80 per cent, much too great to burn efficiently. Stove owners tend to buy what is branded as ‘seasoned’ wood, but this still has moisture content of between 30 and 50 per cent.
The best option is kiln-dried logs, which can provide a more consistent quality, with a moisture content that is generally less than 20 per cent.
There are several reasons not to burn wet wood. It releases more particulates/air pollution into the air than burning dry wood, produces less heat (because the energy is being used to burn the water off first), it takes longer to burn, again because the moisture has to evaporate first, and it creates more sooty deposits in a chimney, which could become a fire risk and will mean the stove needs maintaining
more frequently.
Buyers need less dry wood to produce the same amount of heat, and less wood means fewer emissions and saving money because homeowners don’t have to buy so much wood.
Ian Sams is commercial director at Specflue.