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Generating renewable energy

Solar water heating


  • hot water throughout the year
  • reduced energy bills
  • lower carbon footprint

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.

How do solar hot water heating systems work?

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 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:

  • evacuated tubes – a bank of glass tubes mounted on the roof tiles
  • flat plate collectors, which can be fixed on the roof tiles or integrated into the roof

Larger solar panels can also be arranged to provide some contribution to heating your home. However, the amount of heat provided is generally very small and it is not normally considered worthwhile.

Benefits of solar water heating

Is solar water heating right for your home?

To tell if solar water heating is right for you, there are a few key questions to consider:

Costs, savings and financial support


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 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 £60 a year when replacing gas heating, and £70 a year when replacing electric immersion heating. Savings will vary from user to user.

Financial support

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).


Maintenance costs for solar water heating systems are generally very low. Most solar water heating systems come with a five-year or 10-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, 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 be topped up or replaced, as it breaks down over time, reducing the performance of your system.

Anti-freeze lasts longer if the solar water system is used throughout the year and not left unused during the warmest weeks of the year.

Choosing an installer and system

There’s a lot to consider before installing a renewable system such as solar water heating, but having one will help reduce your energy bills and household carbon footprint.

Our helpful guide offers advice on things to consider when installing a renewable system, including what to look for when choosing an installer or product.