Solar water heating systems, or 'solar thermal' systems, use free heat from the sun to warm domestic hot water. A conventional boiler or immersion heater can be used to make the water hotter, or to provide hot water when solar energy is unavailable.
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 which is stored in a hot water cylinder. A boiler or immersion heater can be used as a back-up to heat the water further to reach the temperature you want.
There are two types of solar water heating panels:
Larger solar panels can also be arranged to provide some contribution to heating your home as well. However, the amount of heat provided is generally very small and it is not normally considered worthwhile.
A competent accredited installer will be able to assess your home and help you choose the best setup to meet your needs.
Find out about planning permission and making the most of your solar hot water system.
The cost of installing a typical solar water heating system is £4,000 - £5,000 (including VAT at 5 per cent for 3.6m2 system). Savings are moderate - the system can provide most of your hot water in the summer, but much less during colder weather.
Solar water heating systems can achieve savings on your energy bills. Based on the results of a field trial, we conducted across a range of household and system sizes, typical savings from a well-installed and properly used system are £50 per year when replacing gas heating and £80 per year when replacing electric immersion heating. Savings will vary from user to user.
|
Existing system |
Fuel bill savings (£/year) |
Carbon dioxide savings (kgCO2/year) |
|---|---|---|
|
Gas |
£50 |
270 kg |
|
Oil |
£55 |
350 kg |
|
Coal |
£65 |
540 kg |
|
Electricity |
£80 |
390 kg |
|
LPG |
£95 |
310 kg |
You may be able to receive payments for the heat you generate from a solar water heating system through the UK Government’s Renewable Heat Incentive (RHI).
|
Household size |
Assumed system size |
Renewable Heat Incentive (RHI) payment (£/year) 1 January 2018 to 31 March 2018 |
|---|---|---|
|
2 person household |
2 m2 |
£200 |
|
3 person household |
3 m2 |
£270 |
|
4 person household |
4 m2 |
£345 |
|
5 person household |
6 m2 |
£445 |
|
6 person household |
6 m2 |
£485 |
Maintenance costs for solar water heating systems are generally very low.
Most solar water heating systems come with a five-year or ten-year warranty and require little maintenance.
Once fitted your installer should leave written details of any maintenance checks that you can carry out from time to time to ensure everything is working properly.
Perhaps the most important thing for you to check for is whether there are any leaks.
Leaks of anti-freeze will produce a strong smell (even if you can’t see any liquid). If you notice this you should contact your installer.
If you are not getting hot water or the solar pipework is cold when the pump is running on warm, sunny days then you should contact your installer.
For peace of mind some installation companies offer an annual service check.
You should have your system checked more thoroughly by an accredited installer every 3-7 years, or as specified by your installer.
It is likely that after this period of time, the anti-freeze that is used to protect your system in the winter months will need to topped up or be replaced as it breaks down over time reducing the performance of your system.
Anti-freeze lasts better if the solar water system is used throughout the year and not left unused during the warmest weeks of the year.
This cost of replacing the anti-freezer is usually around £100.
The other thing that your installer should check is the pump. In a well maintained system, pumps can last for more than 10 years and cost approximately £90 to replace.
Our 'installing renewables' web page covers the key points you need to consider when installing a renewable system, including what to look for when choosing an installer or product.