Hi,
I'm not entirely sure if this post belongs here but there are several components that I think I should consider as part of one solution: Heating and Hot Water.
You may be familiar with my project from the introductions forum but I'll present you with my circumstances in any case. I currently have a Combi Boiler heating our traditionally constructed 2700sq.ft bungalow and providing hot water to 2 showers (right now we use 14000 kWh Electricity and 48907 kWh Gas per annum!).
These entries show the in roof PV system:
http://www.mayfly.eu/2013/11/part-twenty-two-roofing-and-mvhr-and-a-quick-video/
http://www.mayfly.eu/2014/01/part-twenty-six-the-scaffolding-comes-down-at-last/
And here are some photos of the in roof PV system being fitted and the completed front elevation, which looks on to a GII listed building and is inside an AONB and Conservation Area, so we had a fair few planning issues over putting PV on the roof: