The cost of solar thermal water heating systems is determined by the amount of hot water you would like the system to provide. The larger your home, the more evacuated tubes or flat plate panels are required and the more expensive the solar thermal water heating system will be.
Typically, however you should expect to pay between £3,000 and £5,000 including VAT at 5% for a system to cope with the hot water requirements of a 3 to 5 bedroom home. This cost would include the solar collectors, a pump and a new hot water cylinder with a solar coil inside.
Solar thermal water heating systems require very little maintenance but it will probably be necessary to replace the anti-freeze in the solar fluid every few years, which including routine servicing should cost no more than £200.