There’s a huge difference in that between the UK and countries further to the south: for example, pretty much all dwellings in Portugal have outside window shutters whilst in the UK it’s incredibly rare (instead they have inside heavy courtains, so the light goes into the house and the INSIDE gets absorbed by transformed into heat by the courtains) but on the other hand housing insulation is generaly complete total crap in Portugal, but less so in the UK (still not at Scandinavia or Russian levels of efficiency, but way better than Portugal) so in Winter unless one uses massive amounts of electricity/gas for heating, it’s literally colder indoors in Portugal than in Britain.

At the very least both Portugal and Spain are much better adapted to higher temperatures than elsewhere in Europe, and that’s anchored on traditional techniques (such as outside window shutters, houses painted in light colors and the type of roofing used) rather than the brute-force energy-heavy techniques (such as heavy use of Aircon) so common in places like the US.