If we get the envelope, windows and ventilation right, the big utility cost is the energy used for domestic hot water, not the energy used for space heating. (buildingscience.com)
During summer, the solar panel can produce over 90 % of domestic hot water for the property. (politics.co.uk)
First we added the PV array, then a Solar Domestic Hot water and when rebate levels increased a 2nd string of PV. (energysage.com)