Why are AC units in Koh Samui rentals so undersized?

It's a sad reality that many properties in Thailand are built with the intention of being sold, rather than lived in.

A 12,000 BTU air conditioner is generally sufficient for a 40 square meter room. However, if the unit is not functioning properly, it's possible that the filters, fins, or compressor may be clogged with dirt. If that's not the issue, the refrigerant levels may need to be checked. Additionally, the size of the AC is not the only factor at play - insulation also plays a crucial role in maintaining a comfortable temperature.

If the owner isn't desperate for a renter, it may be worth considering installing a new air conditioning unit, and then reinstalling the old one when you move out. This way, the owner won't be left with an oversized AC unit that they may not need.