We have just had quotes for solar powered hot water system. We are in Cornwall, have SE facing roof which is not shaded at all and are going ahead with the order after Christmas. It is not expensive and we can get a grant towards it. The panels we are having put in are filled with glycol and are photosensitive so they work off light, not just sunlight. We also have solar panels for our campervan and our garden pond fountain. Definitley worth it, but do shop around.