Time to come home to a real fire?
To combat rising energy prices, many people may be thinking of firing up their wood burner. But that can have big environmental and health impacts. Ann Link considers what to do to keep a wood fire as eco as possible – or your gas boiler more efficient.
Given the current energy cost crisis, some householders are thinking about turning off their gas boilers altogether and heating their home with a wood fire. However, this may not save money, and the environmental and health impacts can be startling.
Wood-burning stoves were promoted in the past as a low-carbon means of heating. They are attractive and reasonably efficient. But it’s been discovered they aren’t as climate-friendly as once thought. As we reported here, wood-burners not only produce CO2 but also black carbon, creating pollution both inside and outside the home.
In fact, studies have shown that wood burners can triple harmful indoor air pollution. People with asthma can be affected by neighbours’ solid fuel fires. For those without a stove, a fireplace is not only polluting – it’s also massively inefficient. Approximately 80% of the heat goes up the chimney, compared with around 20% with a stove.
But if you do need to burn wood, there are steps you can take to reduce its environmental impact – such as
- Run the fire hot to reduce smoke, and don’t light it at all when bad air pollution is forecast.
- Check that wood is dry, using a moisture meter (15-20% moisture is best).
- Make sure the fire keeps burning hot by adding new wood before the flames die down, and use small diameter wood, not big logs.
- Don’t shut off the air or leave the fire burning slowly overnight.
In terms of what to burn, locally-sourced and sustainably-grown wood is usually best. Buying packs of firewood at the supermarket or garage can be less sustainable, as well as more expensive, (when buying shop-bought wood, check that it is sourced locally and has been dried to be within the required 15-20% moisture level). Worse still is waste or scavenged wood that’s been painted or treated and can give off toxins when burned. Particle board (MDF), plywood, cardboard or glossy paper should be avoided for the same reason.
Making gas more efficient
If you or someone you know are finding it difficult to meet energy bills, it’s important to seek help now. It may be more affordable and efficient, as well as cleaner, to measure and reduce gas use than to turn to other fuels.
For example, if you can get a smart meter from your energy supplier it will measure how much gas is being used and show the cost. There are also ways to use gas more efficiently such as reducing the boiler flow temperature. See tips from Which? and the Energy Saving Trust.
These efficiency savings could be even greater than the amount saved on gas if you buy and burn wood instead. This is partly because new gas boilers are very efficient and gas is a very energy-dense fuel.
In the longer term of course, greater insulation and other heat sources such as air source heat pumps need to be the large-scale solution to keep our homes warm – affordably and sustainably.