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.

The benefits of solar water heating

• Hot water throughout the year. The system works all year round, though you'll need to heat the water further with a boiler or immersion heater during the winter months.
• Reduced energy bills. Sunlight is free, so once you've paid for the initial installation your hot water costs will be reduced.
• Lower carbon footprint. Solar hot water is a green, renewable heating system and can reduce your carbon dioxide emissions.

How do solar 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 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:

1. Evacuated tubes

2. 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 as well. However, the amount of heat provided is generally very small and it is not normally considered worthwhile.

Is solar water heating right for your home?

Things to consider

• Do you have a sunny place to put solar panels? You'll need around five square metres of roof space which faces East to West through South and receives direct sunlight for the main part of the day. The panels don't have to be mounted on a roof however. They can be fixed to a frame on a flat roof or hang from a wall.

• Do you have space for a larger, or an extra, hot water cylinder? If a dedicated solar cylinder is not already installed then you will usually need to replace the existing cylinder, or add a dedicated cylinder with a solar heating coil.

• Is your current boiler compatible with solar water heating? Most conventional boiler and hot water 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, a solar hot water system may not be compatible.

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.