Why - to cut our extortionate fuel bills and our carbon emissions - we are off mains gas and run on oil / electricity.  Calculated it would be about an 8 year pay back though of course it is very hard to tell as at the same time as installing we are also making other lifestyle changes (generally increased awareness) that also impact on hot water use and costs.

Expectations - wasn't quite sure what they would deliver but hoped they would help keep the tanks warm, and cut our costs and carbon.

Outcome - better than expected.  Costs: I think our water heating went off around the begining of March this year and we have only had to boost it (with the immersion) on the overcast days since.  Even when we have to boost it, it is a relatively small job, from a temperature of around 24-30 degrees up to around 40 degrees.

Awareness: It makes me very aware of what we use, how hot we need it and when we use it.  Also of how much heat is lost through silly things like using the hot tap to wash your hands / do little bits of washing up, but not actually running it long enough to get the hot water, so all you do is waste it rather than benefit from it - therefore just use the cold tap in the first place if you don't need the hot.  39 degrees is fine for a shower, and our washing machine goes on on the mornings of sunny days to take advantage of the solar heating potential.

Installation:  Elemental did a very neat job and far from thinking they look clunky on the roof I'm rather fond of them now.  Our house was also slightly more complicated than standard and I cannot praise them highly enough for the very good job they did of sorting out odd teething trouble on the first couple of days.

As you can see I'm a very happy customer and more than willing to give anyone any more information if they want it - these things are brilliant and every house should have them in my view.  Beware however of cowboy installers - I am aware of some high pressure sales techniques being used in the industry.

Best wishes, Rowena