the_third , 10 months ago

That’s why you use insulating bricks like these:

https://feddit.de/pictrs/image/1886126e-1bea-4e3f-ad3c-67780db1a1aa.png

See how there are as few direct connections between inside and outside as possible. The whole thing is very light too, so it has very little thermal mass. This is combined with a white surface outside and that transfers very little heat. My 200m² house requires maybe 1.5kW of heating at -10°C outside in the winter. I have no AC, in summer we just leave the windows open until 6am and then shut the blinds automatically when the air heats up.