As winter approaches, the vast majority of us will be using gas boilers to keep our homes warm. But, given that around 20 per cent of the UK’s carbon emissions come from heating buildings (and with a national target of reaching net zero by 2050), is there a more climate-friendly way to stay cosy as the days get colder?
From heat pumps and low carbon boilers to solar panels, we’ve rounded up the most carbon-conscious home heating systems.
Heat pumps provide low carbon heating and cooling by transferring heat to or from a source outside of your home.
Air source heat pumps
Cost to install: £15,000 – £18,000
Suited to: Houses in milder climates
How do they work? Air source heat pumps draw energy into your home from the outside air. Air-to-air pumps, known as ‘air conditioners’, provide space heating only while air-to-water pumps provide both space and water heating.
Pros: Energy-efficient heating in milder climates with low running costs. The cheapest type of heat pump to install, they also take up the least amount of space.
Cons: The colder the area, the less useful an air source heat pump becomes. This is because the pump will need to work harder to warm up the cold air taken from the outside. If you live in an area with exceptionally cold winters, ground and water source heat pumps would be more suitable.
Ground source heat pumps
Cost to install: £20,000 – £40,000 (depending on whether it’s a horizontal or vertical system)
Suited to: Houses in colder climates
How do they work? Ground source heat pumps rely on the temperature of your soil, which is relatively constant year-round. This means it does not need to work significantly harder in the winter compared to the summer months. A horizontal ground source heat pump system is installed one to two metres below ground, while a vertical system (which is more costly) needs to be installed 50-100 metres deep.
Pros: Usually the most efficient green home heating system to run.
Cons: Pricey to install.
Water source heat pumps
Cost to install: £10,000
Suited to: Houses near a body of water, such as a lake or pond
How do they work? Water source heat pumps extract energy by pumping water from the source directly through the pump. They can be very efficient, but are only practical if you live near a body of water, such as a lake or pond.
Pros: Cheaper than ground source pumps to install and provide steadier heating, particularly if the body of water is 5-8°C.
Cons: If your water source freezes during winter, you will probably need a backup heating system.
If you’re looking to upgrade your oil or gas boiler to a more climate-friendly one, you could choose an electric combi or biomass boiler. There is also a micro-CHP system, which uses gas to generate both heat and power at the same time.
Electric combi boilers
Cost to install: £1,000 to £4,500, depending on your property and existing infrastructure
Suited to: Smaller homes with less storage space
How do they work? Electric combi boilers use electricity to warm your house and provide hot water. Because they don’t require an oil or gas tank, they are compact.
Pros: Highly efficient as they don’t need to burn fuel, and therefore lose less energy. Unlike gas and oil burners, electric combi boilers are virtually silent due to the lack of fast-moving elements inside. They are also easy to use. Most come fitted with digital touch screens and controls that you can remotely manage with home tech like smart thermometers.
Cons: More expensive to run than oil and gas boiler options as they rely on electricity. They also heat water on demand rather than continuously. This means they won’t produce as much hot water and may struggle to heat larger homes.
Cost to install: £5,000 to £15,000
Suited to: Larger homes that need a lot of hot water
How do they work? Biomass boilers are powered by burning biomass – typically sustainably-sourced wood pellets. They are ideal if you want to replace your current gas or oil boiler with one that performs similarly but doesn’t produce as much carbon.
Pros: Lower operating costs than other boilers, such as an electric combi.
Cons: About as large as a gas or oil option and will be less energy-efficient than an electric system. In colder months, biomass boilers can also produce a significant amount of noise, or ‘kettling.’
Micro-CHP systems (or micro combined heat and power systems)
Cost to install: £4,000 to £6,000
Suited to: Nearly all homes
How do they work? Micro-CHP systems generate heat and electricity simultaneously using the same energy source. They are similar in size and shape to gas boilers and are powered by gas mains or liquefied petroleum gas (LPG). While they still rely on fossil fuels, micro-CHP systems are low-carbon because they burn gas to provide both electricity and heat at the same time.
Pros: Highly-efficient way of using gas for both heat and power.
Cons: Costs more than a traditional system to install, although maintenance and servicing costs should be comparable. It probably won’t provide enough electricity to cover all your home’s needs, but will reduce the amount of energy that your home will draw from the grid.
Cost to install: £3,000 to £5,000
Suited to: Houses in southern England and Wales.
How do they work? Solar panel heating systems use special solar collectors installed on your roof to gather energy from sunlight.
While some areas are a better fit for solar power than others, lower solar potential doesn’t rule out the use of these heating systems. It only means that in those regions, they may be slightly less effective. In fact, experts say that devoting just one per cent of the UK’s land to solar panels would be enough to generate electricity for all of its needs.
Pros: Once installed, they provide zero carbon, no-cost energy.
Cons: Most solar heating systems will heat only around half of the hot water a home needs, or offer anywhere between 40 and 80 per cent of space heating. Therefore, you’ll also need to maintain an auxiliary heating system – like a boiler or heat pump – that can provide the rest of the heat.