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Blog Post 9 February 2021 Updated 1 April 2022

A quick guide to low carbon heating

Please note: the Renewable Heat Incentive closed to new applications on 31 March 2022.

To reach net zero carbon emissions by 2050, we will need to change the way we heat our homes and buildings.

In the UK, we will need to phase out oil and gas heating systems like boilers to reduce our dependency on fossil fuels, replacing them with renewable, low carbon technologies. These systems can help to reduce carbon dioxide emissions from households.

Here, we take a closer look at three renewable technologies – heat pumps, solar water heating and biomass – to help you decide which one will suit your home.

Heat pumps

There are two main types of heat pump – ground source and air source – in addition to the less common water source heat pump. Heat pumps use less fossil fuels than most other systems, so are a more sustainable, low carbon source of heating.

They work by absorbing heat from a source and transferring it to a fluid, which is compressed to increase the temperature further. The heat is typically transferred from the fluid into water, which is then used to provide heating and hot water to your home.


  • lower fuel bills – especially if you replace conventional electric heating
  • reduced household carbon emissions, depending on which fuel you replace
  • heats your home and your hot water, and works all year round

Things to consider

Our blog takes a closer look at the main differences between air source and ground source heat pumps. You’ll need to consider whether you have space for a heat pump; ground source heat pumps require garden space to install a pipe loop below ground, while air source heat pumps require space around them to get a good flow of air.

Since heat pumps work best when producing heat at a lower temperature than traditional boilers, it’s important that your home is well insulated and draught-proofed for the heating system to be effective.

You should always check whether you require planning permission from your local planning authority before installing any new renewables system. Installing a ground source heat pump can be more disruptive, so it’s worth combining the installation with other building work if you can.

How much will it cost?

Installing a heat pump can range from around £9,000 – £11,000 for an air source heat pump to up to £19,000 for a ground source heat pump. How much you can save will depend on the system and fuel type you are replacing. Your savings will be affected by several other factors, including how efficiently you use the controls, as well as existing fuel costs.

You will still have to pay fuel bills with a heat pump because they are powered by electricity, but you will save on the fuel you are replacing. If the fuel you are replacing is expensive, you are more likely to make a saving. Once you’ve installed a heat pump, you may be eligible to receive payments for the heat you generate through the UK Government’s Renewable Heat Incentive (RHI).

Air heat pump beside house,

Solar water heating

Solar water heating systems use solar panels, called collectors, fitted to your roof. These collect heat from the sun and use it to heat up water that’s stored in a hot water cylinder. A conventional boiler or immersion heater can be used to make the water hotter, or to provide hot water when solar energy is unavailable.


  • hot water throughout the year – although you might need a boiler or immersion heater during the winter months to boost the water temperature
  • reduced energy bills – after initial installation costs, sunlight is a free, renewable source of energy
  • lower carbon footprint – solar water heating is a renewable heating system, reducing your household carbon dioxide emissions

Things to consider

You’ll need around 4-5 square metres of roof space for solar panels, which receives direct sunlight for most of the day. Ideally, your roof should face east to west, however solar panels can also be hung from a wall or mounted to a frame on your roof.

Check that your conventional boiler and hot water cylinder system is compatible with solar water heating. If you have a combi boiler and no hot water cylinder, the technology may not work with your existing heating and hot water system.

Most domestic solar water heating systems below a certain size don’t require planning permission. However, check with your local planning officer, especially if your home is a listed building or in a conservation area.

How much will it cost?

The cost of installing a typical solar water heating system is £4,000 – £5,000. Savings are moderate – the system can provide most of your hot water in the summer, but much less during the winter months.

Solar water heating systems are also eligible for payments under the Renewable Heat Incentive. Visit our advice page for more information on solar water heating, including potential RHI earnings.


Biomass systems burn wood pellets, chips or logs to heat a single room, or to power central heating and hot water boilers. While burning the wood does emit carbon dioxide, it’s at a lower level than coal or oil provided the fuel is sourced locally. Biomass is considered a sustainable option as long as new plants and trees continue to grow in place of those used for fuel.


  • affordable heating fuel – although the price of wood fuel varies, it’s often cheaper than other heating options
  • lower carbon option – the carbon dioxide emitted when wood is burned is the same amount that was absorbed over the years the plant was growing

Things to consider

If you’re thinking of installing a biomass boiler, you’ll need space for the boiler itself, as well as somewhere to store the pellets, chips or logs. You’ll also need a flue that meets regulations for wood-burning appliances.

There are several options to choose from, which generate heat in different ways and can play different roles – for example, providing hot water, space heating, or both. You should try and source a local fuel supplier and ensure they are on the registered list of sustainable biomass fuel suppliers. Finally, while you may not need planning permission, you should always check first.

How much will it cost?

For biomass boilers, an automatically fed pellet boiler for an average home costs between £11,000 and £17,000, including installation, flue and fuel store. You’ll also have to factor in the cost of fuel deliveries – whether that’s pellets, chips or logs. Logs tend to be cheaper than pellets, but costs depend on the wood suppliers in your local area, as they can be expensive to transport.

As with other renewable heating technologies, you may be eligible to receive payments for the heat you produce from a biomass boiler or pellet stove with back boiler, under the Renewable Heat Incentive scheme. Certain conditions apply, so check out our biomass advice page if you’re thinking of installing a wood-fuelled heating system.

Combining technologies

Different renewable systems can complement each other. For example, solar water heating works well with heat pumps, because together they can provide efficient water and space heating.

Installing a renewable heat technology when you’re doing other home renovations can help save on installation costs – combining jobs and minimising disruption too. As with all investments, make sure you do plenty of research and ask any potential installers questions. Your installer and product should be certified under the Microgeneration Certification Scheme (MCS) and we recommend getting at least three quotes from different installers.

Last updated: 1 April 2022