The turbine looks to be a good investment so far. The Feed-in-tarrif means that it should pay for itself in about 8 - 10 years, and that tarrif lasts for 20 years, the expected life of the turbine.

I have double insulated quite a bit of the wall area of the house. It has cavity walls but the cavity is not filled as it is too damp (not that well built). I have put a plasterboard surface up with an insulation filled cavity on many parts of the external walls.

I am working on the roof space, putting in cross beams at 90 degrees and creating an 8" depth of insulation with a floor surface above that for storage, then insulating the inside of the roof rafters with a reflective foil "quilt".

It may be possible to use a ground heat system but I will have to get some expert knowledge about how to set it up without damaging the field drains' effectiveness.