The cheapest sustainability upgrade in a tropical flat is the one you choose before moving in
I work on supply chain reporting for a manufacturer in Udon Thani, so I spend my days looking at other people's emissions numbers and then went home to a flat that was quietly terrible.
The thing I did not appreciate until I measured it: in this climate, the orientation and envelope of the building decide most of your household energy use, and no amount of behaviour change afterwards catches up. I put a cheap meter on the air conditioner in two consecutive flats, same size, same city, same settings. The difference across a year was close to a third.
What made the difference, roughly in order:
Which wall gets the afternoon sun. West-facing bedroom means you are cooling a wall that has been absorbing heat since noon.
Whether the roof or the floor above you is occupied. Top floor under an uninsulated slab is a different building from the same flat two floors down.
Window area versus shading. Big windows are lovely and, unshaded here, they are a heater.
Whether the unit was ever retrofitted with an inverter air conditioner or still has the old fixed-speed one the landlord installed a decade ago. Ask the model. It is on the indoor unit.
None of this is exotic, but none of it is in a listing either, and it all becomes fixed the day you sign. When I was comparing my options I used https://thailand-real.estate/ mainly to look at floor plans and orientation across a few areas before visiting, which narrowed the shortlist a lot.
Curious whether anyone here has pushed a landlord to replace an air conditioner as a condition of signing. I asked once, was refused, and later learned two neighbours had succeeded by offering a longer lease.