Thanks for that
@Effendi, but I've had very little to do with "green" which I'm quite cynical about.
It annoys me that even the latest houses might have plenty of expensive technology, but they don't give much thought to passive.
You should always go for the passive options first, like insulation, before you start looking at high tech savings, which are often snake- oil.
One factor I went for with my house was it faces due south, and the windows are fairly large, so the solar gain in winter is quite dramatic.
Plus the woodburner gives out worthwhile cheap heat, at the same time, giving a healthy air- change.
It's backed up by an Intergas condensing boiler, which is very simply built, with very little to go wrong.
As a rule of thumb, the more expensive technology, when it goes wrong, will cost a fortune to fix, and will be very difficult to find someone capable of fixing it, losing all savings.