just started looking into this as an add on to the biusness ,solar water heating is not worth it!! only produces 25% of water you need and the pay back takes years.air source heat pumps which will produce all your heating needs + your hot water is best,wait until the 20th oct as the government will clarify on what incentives they will give if you have it installed.but if its anything like the the pay back on solar electricity its a liceance to print money.what ever you do ,do not sign up to the free installations of solar which are being offered as you may save a couple of hundred quid a year on your fuel bill but you sign over to these companies the right to claim back thousands of pounds from the government.beg burrow or steal the money and pay for it your self.rough install cost for a full installation of solar power £10,000 for a large 4 bed ,you can then claim approx £1000 per annum off the government for up to 25 years (do the math you wont get that interest in the bank) the national grid is predicting black outs within the next 5 years and cant cope .for every kw used in your house the grid has to produce 3kw ,2kw are wasted heating birds feet on the cables,thats why the goverment are giving these incentives.I would strongly advise any one who has no gas to look at the air source heat pumps as over oil its a no brainer (no oil tank,no mess,no theft,50% more efficient,government incentives,costs the same to install!!!!) this is not a sales picth as in the south and dont travel, just some informed advise.