How does it work?

Solar panels are designed to absorb the sun’s energy and transfer this to your water heating system. They are a simple idea made more efficient by using modern materials and technology to make sure the panels trap as much of the sun’s heat as possible and lose as little of this heat as possible.

Solar panels absorb heat from the sun which heats up a fluid passing through the panel in pipes. The fluid is then piped through a hot water tank to heat the hot water supply.

The way in which solar water heating systems fit into a domestic heating system varies quite widely due to the different types of boilers and heating systems in domestic properties. A common system would use a heat exchanger in the hot water tank (see diagram opposite).

What does it look like?

The panels are generally fitted on to the roof and a typical home system might be 2-4m2 in size. There are two basic types for domestic water heating, one looks like a simple flat black panel (flat plate collectors) and has a similar appearance to a sky-light. The other system appears as a collection of glass tubes (evacuated tube collectors).

Why is it important?

Solar water heating is a simple way to harness energy from the sun to reduce pollution caused by energy used in water heating.

Solar water heating systems heat water whilst releasing only negligible amounts carbon dioxide which contributes to climate change. These negligible emissions are caused by the energy used by the systems circulating pump, these can be avoided by using by using green electricity or if the system can be designed without a pump. The solar panels produce no local pollution during operation and their manufacture causes no significant environmental impacts compared to other industrial processes.

How much energy can it generate?

In the UK, solar water heating systems for the home are designed to work in conjunction with another water heating system, such as a gas, oil or wood boiler.

An average home system might provide almost all your hot water over the summer. Through the rest of the year it will pre-heat the water which will then be brought up to temperature by the conventional hot water system. Over the course of a whole year most solar panels should provide around 50-60% of the total energy used by your hot water system.