Hot water straight from the sun may sound too good to be true, but even in the UK a solar hot water system can supply you with over 50% of your hot water needs over the year (the other 50% coming from a conventional gas boiler or electric heater). With recent high energy prices, and concerns about Climate Change, more and more people are looking to take advantage of this tried and tested technology to save energy in their home.

A solar hot water system works by capturing the sun's heat with solar panels fitted to your roof. This transfers the heat to a fluid, which in turn transfers the heat to a hot water cylinder to store the heated water during the day.

A surprisingly large amount of energy can be captured this way, even in cooler climates like the UK. Over 1000 kwh of energy is received each year in the UK on each square metre of surface. That's about 60% of the solar radiation found at the equator. Even on cloudy days we receive energy from indirect sunlight and this energy replaces the gas or electricity that would otherwise be used to heat water. Altogether this adds up to a big saving on fuel, and a big benefit for the environment. Each solar hot water system saves around half to three-quarters of a ton of carbon dioxide each year

Solar hot water is usually the most cost effective renewable energy system you can install at home, with a shorter payback than other options, e.g. wind or solar electricity generation. The payback is improved even more by the government grants that are available in the UK.

It is also a tried and tested technology that has been around since the 1970s. Very little maintenance is generally required for solar hot water systems. They normally come with a 10 year guarantee. They generally only need a basic check by you once a year and a check by a professional every 3-5 years.

Before you decide to move ahead with the purchase of a solar hot water system you need to check that your property is suitable. You will need 2 to 5 square metres of southish facing roof space (i.e. southeast, south, or southwest facing), that has little or no shading during the day. You may also need space to locate an additional hot water cylinder if it is needed. Solar hot water systems generally work well in partnership with condensing boilers. They do not generally work well with combination boiler systems. Installation with these usually involves extra cost.

Installation costs vary due to factors such as size of the solar panels, type of roof, the existing hot water system and where your house is. The typical installation costs are between £2,000 and £5,000, although you can get several hundred pounds in grants from the UK Government to help with these. The cheapest systems are generally those based on ‘flat plate collectors', which will cost between £2,000 and £3,000. Another type of system (an ‘evacuated tube' system) generally costs £3,500 to £5,000, but needs less roof space to provide the same amount of water heating, because it is more efficient. An installer will help you decide which type of system is best for you.

If you are interested in installing a system, you should contact a reputable installer to carry out a survey of your home, and get a quote. They will be able to assess your property's suitability, advise you on which system is best, give you a quote and help you with grant funding. Before you can qualify for grant funding from the UK government for a system like this, you need to have already installed some basic energy efficiency measures in your home, such as low energy light bulbs, insulation and efficient heating controls.