I live in a somewhat warmer climate than the UK can offer, so the whole dynamic is different here. Although heating is required in the winter, it is a much shorter period, 3~4 months, and even then it seldom gets down to single figures.
But electricity here is ridiculously expensive compared to the average salary and there is little competition between the limited number of service providers.
I decided to install some PV solar panels (grid-tied) to offset some of my own consumption. There are no grants or incentives here for this. After some experimentation with a home-made tracker I came to the conclusion that was a waste of effort and not worth the hassle, it worked out better just to spend the money on more panels, space permitting of course.
I ended up with 1.5kW of static panels. They heat the hot water for the most part, once that's hot enough any excess runs the meter backwards (shh!). If it gets really warm in the mid-summer months (it does vary from year to year) the air conditioning may have to come on for a few hours in the evening to cool the bedroom down- it's an A+ rated (inverter) system by Daikin and is remarkably efficient. Also doubles up as heating in the winter.
Building insulation standards here have been improved somewhat in recent years, and all new-builds must have insulation in the floors, walls & ceilings, even the glazing has to meet strict standards. Sadly my house is 10 years old so doesn't have much in the way of insulation, and I'm not buying a new one just for that!
Nonetheless, with a few sensible adjustments (LED lighting, efficient fridge etc.) and with the help of the solar panels, I have reduced the overall consumption to less than half of what it was just over a year ago, so very pleased with that.
I feel it's now at the stage of diminishing returns, where any further improvements are unlikely to be cost-effective.
