The UK’s houses are still designed to retain heat. In an age of global warming, that needs to change.
When you need ACs, there is lots of sun, so lots of solar. So maybe not extra grid load if houses have their own solar.
I also close windows and curtains in the sun. Thinking of adding shutters.
Interestingly enough, solar panels work much better when it’s cold. There are a lot of improvements the UK could make to mitigate this problem for winter and summer. Solar panels are a must, followed by good insulation and subsidies for heat pumps ac pumps.