South Africa here, it's not common to build energy efficient houses although it's gradually getting slightly better.

I'm busy changing all my windows to double glazed (single glazed is the norm, believe it or not) and proper insulation in above the ceiling.

Instead of freezing my ass off every winter it's now super pleasant, and it's cooler in summer. Such a non-brainer - I just don't understand why people don't do this more.