The UK’s government and heating industry are debating how we can reduce our carbon emissions while still heating our homes and businesses effectively. However, while they research and test state of the art renewable energy technology such as heat pumps, smart heating controls and a hydrogen network, there are some people who still rely on coal or wood fired heating systems.
Whether motivated by necessity or nostalgia, in a world where every unit of carbon tips the balance towards climate change, is there anything to be said for using the oldest heating fuels of all?
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Coal and wood: solid fuel heating
There are two types of solid fuels: biomass and minerals. In most domestic heating situations, biomass refers to wood whether it is burned in logs, chips or pellets. Mineral fuels include bituminous coal, natural smokeless fuel (anthracite and dry steam coal), manufactured smokeless fuel and manufactured non-smokeless fuel.
The most common biomass fuel used is wood. Wood is available in many forms including logs, manufactured logs (usually a mixture of wood and wax), chips and pellets.
Solid fuels like wood and coal can be burned on open fires or in closed appliances like wood burning stoves, cookers or sometimes in a gravity fed boiler.
Note: It is not a good idea to burn general waste in a solid fuel appliance as this can produce pollutants and toxins which can be damaging to the health of you and your neighbours.
Home heating with coal
Having an open coal fire in the front room used to be the norm before more efficient and lower maintenance technology arrived. It is no longer a popular choice as a main source of heating, but many people still enjoy the warm glow of a real fire in their home. Having said that, there are some homes which still rely on a coal-fired boiler which needs to be manually topped up with fuel and cleaned out on a daily basis.
Home heating with wood
Wood can obviously be burned in a wood burner or on an open fire or, but more people are now investing in biomass boilers. These boilers are fueled by biomass chips or pellets (which are mainly comprised of wood) either manually or via an automatic-feed function. Biomass boilers require a lot of fuel which either needs to be found naturally or delivered as well as lots of space to store it in.
Environmental impact of heating with coal or wood
Coal is not an environmentally friendly heating fuel. When you compare an equivalent coal fired heating system to a natural gas fired system (which over 80% of UK homes currently use), coal produces twice as much emissions as carbon including particles, sulphur dioxide and carbon dioxide than an equivalent natural gas fired system.
The environmental impact of heating your home with wood, however, is not so easy to determine as it can depend on several factors. Wood can be a carbon neutral fuel, i.e. it does not emit any more carbon into the atmosphere than the tree absorbed while it was growing. So if you are collecting and burning untreated wood which is in your local area, wood can be a green heating option.
However, if you have wood delivered to your home, depending on the distance it has to travel, the transport involved will be adding carbon to the atmosphere. You also need to consider the methods used to source and prepare the fuel, e.g. electricity used to power chainsaws. You also need to consider your location as a wood fueled appliance can produce more local emissions than an equivalent gas appliance which can be a problem in densely populated urban areas but not so much in rural areas.
Smoke control areas
If your local authority has declared the area a Smoke Control Zone under the Clean Air Act 1993, you will have to ensure any fuel you use is approved as smokeless or that your appliance can burn without producing smoke and is therefore exempt. Wood and standard bituminous coal are not authorised fuels, so if you want to burn them you need to ensure you are using an exempt appliance.
To minimise the emissions your appliance produces you should try to ensure that the fuel you use is clean and dry. When fuel is wet it will burn at a lower temperature producing more emissions. Wood which has been painted or preserved will also produce higher levels of toxins.
Maintaining solid fuel appliances
To keep solid fuel appliances working efficiently and safely it’s important to carry out the proper maintenance on a regular basis. Your appliance manufacturer will be able to provide detailed instructions which may include:
- Sweeping the chimney
- Ensuring the appliance is adequately ventilated
- Cleaning flues on boilers
- Emptying the ashtray or can
- Removing and cleaning throat plates on heaters.
If you have any concerns about the safety of a solid fuel appliance, e.g. you smell fumes, open all windows and doors and let the fire die down. The appliance should be checked by a qualified solid fuel engineer which you can find on the HETAS website.
Buying solid fuels
To ensure you are buying high quality approved coal you should always look for the Approved Coal Merchants Scheme logo as these suppliers are fully trained to provide information and advice on the correct use of solid fuel. There isn’t an equivalent approval scheme for wood so it is best to ask your appliance manufacturer or installer for the best fuel to use.
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Choosing a New Heating Fuel
If you would like to change your heating system to run on another type of fuel which is more environmentally friendly, more convenient and/or cheaper, there are several options open to you. Choosing the right heating fuel for a home comes down to which of the following factors is most important:
- Cost of installation.
- Running costs.
- Ease of use.
- Environmental impact.
Cost is usually one of the biggest factors for many people, which is just one of the reasons why it’s important to compare quotes for any heating system. Technology prices and the cost of labour can vary significantly from company to company, so take the time to shop around.
The main options for heating fuel in the UK are:
- Mains gas
- Electricity (solar or traditionally generated).
Gas is usually the cheapest fuel, delivers a high level of efficiency, is convenient to use (it delivers heat to the home quickly and on demand) and – of all the fossil fuels – is the cleanest in terms of carbon emissions*. Over 80% of homes in the UK are connected to the mains gas grid for heating and hot water production, but off-grid homeowners have to find alternative heating systems.
*Gas is a better option than coal and oil in terms of carbon emissions, but it is still harmful to the environment which is why gas boilers are being banned from new build homes from 2025.
For homes not on the gas grid, oil fired heating has been a popular choice for many years. Whether using kerosene or gas oil, it is delivered by a lorry and pumped into a tank which is stored on the property either above or below ground. These tanks need to be monitored and maintained regularly to ensure it does not run out of fuel. After gas, oil fired heating is usually the cheapest option. While oil emits less carbon than coal, it is higher in emissions than gas and the price of oil can fluctuate dramatically depending on demand.
LPG (liquid petroleum gas) is another alternative for off-grid homes which produces less carbon than oil. Like oil, it is delivered either in a tank or refillable bottles, but it is often more expensive.
Many homes which are not on the gas grid choose to use electricity to heat their home and hot water. Historically, the downside of using electricity has been that the production process generates a lot of carbon emissions and that it is expensive. However, as more and more electricity is generated through renewable technologies such as solar panels and wind farms the environmental factor is less of a concern. In addition, if you install solar PV panels on your home you can power an electric heating system with clean, free energy.
Whether you use renewable or traditionally generated electricity, you can use it to power an electric boiler, storage heaters, electric radiators, water heaters and heat pumps. Air source and ground source heat pumps use a small amount of electricity to extract latent natural heat from either the air or ground and use it to heat water for your home. Heat pumps produce no carbon emissions, are very cheap to run and simple to maintain.
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While coal and wood can be a cosy and effective fuel for wood burning stoves or open fires as a secondary heating source, if you are heating your home with coal or wood as the main fuel, it is definitely worth investigating an alternative system. There are now several options available which would be cheaper and easier to run and more environmentally friendly.
To find out more about air source and ground source heat pumps or a biomass boiler and how they could work in your home, head over to Boiler Guide for advice and free quotes from professionals in your area.