Solar water heaters harness the heat from the sun and are efficient enough to provide all of your summer hot water and at least a third of your hot water over the whole year. You will need between 3m2 and 5m of solar panels, depending on the type that you choose and a southerly facing roof on which to mount them. You’ll also need a large and lagged hot water cylinder to store the hot water. Solar water heaters cost between £3,000 and £5,000 to install and are relatively easy to maintain and use. They are also considered to be the most cost-effective form of renewable power available in the UK.
Heaters vary from the simple to the sophisticated, from the D1Y – paint a radiator black, stick it on a south-facing roof and connect it to your hot water tank – to the hi-tech, vacuum-filled glass tubes that capture 90°/o of the heat from the sun fitted with electronic controls and solar powered pumps. The most cost-effective are the simpler ones, but all solar panels provide good quantities of warm water for much of the year.
Nearly all require a hot water storage tank and therefore don’t work well if you have an instantaneous ‘combi’ boiler in your home. That’s because you have to store the hot water that is generated in the day, so that you can benefit from it later when you actually need to use it. The panels themselves vary in size depending on the type that you go for and the number of people in your home, but they should be located on a south facing sloping roof to maximise the amount of heat that they capture from the sun.