Looking for an air conditioner for small bedroom of 130 sq feet. When I look online at btu recommendations they say that 6000 more than adequate but the smallest unit I can buy locally seems to be 9000 which is 50% above recommended which I’m quite happy to have. However the shop I’ve been to says I need 12000 for that size room when I ask why he says Thailand always need more. So suggestions please, what size does anyone suggest. 

130sq ft = about 14 m².

 

Standard Thai guesstimate is 600-700 BTU per m², so 9,000-10,000 sounds about right unless you need arctic conditions for your pet penguins or the room has a heavy heat gain from sun on the walls, windows and roof.

 

A 12,000 BTU inverter type wouldn't be outside the "fairly sensible" range.

 

Try another shop ???? 

 

 

You could try out the Carrier Thailand online BTU calculator here.

I have a 9000btu inverter in a 18m2 bedroom and it works well.

From my experience 9000 BTU should be more than enough. For non-inverters - an oversized unit will not take out much moisture from the air because the compressor runs always only a short time. On the other hand an undersized unit could make the air very try because the compressor runs long and so more water will condense at the cooling fins. 

Encid. Had already tried the Carrier calculator which recommended 9600 btu. 
 

But thanks everyone for your replies, I’m going to stick with a 9000 btu model despite what the shop says. 

9000 BTU sounds more than enough for 12m²

 

We have 13k in bedroom (23m²), overkill, and a 24k in main room (83m²), which includes the kitchen.  More than adequate, and damn chilly at times, though well build house.

 

Mitz rep said it wouldn't be enough ????