Solar Thermal

What is it?

Solar water heating systems (also known as solar thermal) use free heat from the sun to warm domestic hot water. A conventional boiler or immersion heater is then used to make the water hotter, or to provide hot water when solar energy is unavailable.

How does it work?

Solar water heating systems use solar panels, called collectors, fitted to your roof. These collect heat from the sun and use it to warm water which is stored in a hot water cylinder. The panels work throughout daylight hours even if the sky is overcast and there is no direct sunshine.

A solar water heating system main components are:


  • Solar panels

Solar panels are fitted to a roof and retain heat from the sun and transfer this heat to a fluid.

  • Hot water cylinder

The heated fluid is passed through a heat exchanger in the hot water cylinder.  The cylinder stores the hot water that is heated during the day for supply when hot water is required.  A boiler or immersion heater can be used as a back up to heat the water further when the solar water heating system does not reach the desired temperature.

Additional Information

Most conventional boiler and hot water coil cylinder systems are compatible with solar water heating. If your boiler is a combination boiler (combi) and you don’t currently have a hot water tank then a solar hot water system may not be compatible.

In England, most solar water heating systems don’t need planning permission but it is always best to consult your local planning office.

Maintenance costs are very low. Most solar water heating systems come with a 5-10 year warranty and require little maintenance.