I have a 50 s/m studio and over the years have always kept my AC set at 26-27 degrees while using several floor fans simultaneously to move the air around. It has generally been comfortable for me.

When some AC technicians came to service my old unit, they admonished me to never run it at more than 24 degrees but because of language differences, I could never get a good explanation as to why.

The old AC finally got way too inefficient and loud so this past week I bought a new Samsung 19,000 BTU with inverter. It was installed 2 days later and once again, as the technicians were showing me how to use the remote (Instruction manual in Thai) they too stressed not over 23 degrees. Language again hindered me from an understandable explanation.

I suspect it has more to do with de-humidification efficiency than anything else but I really don't know. I really hate to run it that cool.

Almost all the advice I find on the internet says to set it at as high as is comfortable and that when the outside temp. exceeds 35C, each degree you set below 25C can cost 2% to 3% more in power costs over time. If I can get away with 27 Degrees, that is what I want to use.

Can anyone explain why the technicians are stressing 23 degrees and will I end up costing myself more if I run in the 25 to 27 degree range?

The new Samsung is so quiet I can't even believe it's running when it's on. My old one sounded more like a diesel locomotive. It's been cool enough the last few nights that I didn't need it but during the heat of the day it seems to work well. I won't really know just how effective it will be until hot season arrives but I suspect it will be up to the task.

Maybe they think you are going to use it in a tour bus.

No, it doesn't make sense unless he was saying not to turn it below 23-24 degrees as the compressor may run continuously. 50 sqm and 19,000 BTU may be a little over sized depending on the sun exposure and insulation and could cause quick cycling of the compressor. But I think there is a communication error somewhere.

Maybe they think you are going to use it in a tour bus.

No, it doesn't make sense unless he was saying not to turn it below 23-24 degrees as the compressor may run continuously. 50 sqm and 19,000 BTU may be a little over sized depending on the sun exposure and insulation and could cause quick cycling of the compressor. But I think there is a communication error somewhere.

They were definitely stressing not over 23 degrees. No miss-communication there. "No!, No!, 26 mai dai, mai dai!! Mai dee mahk mahk!!"

No insulation. Two walls have no outside exposure but one south facing, lengthwise wall is open to the morning sun and gets very warm to the touch.

I went to quite a few dealers and when most went to their charts, they advised 30,000 BTU!!! I figured out that air conditioner prices here run to around 1.5 to 1.75 Baht per BTU for decent units.

My sleeping area (about 20 s/m) is curtained off with ceiling to floor heavy drapes so I figured that even if the 19,000 BTU was not sufficient for the whole room, it would at least cool where I slept which was most important to me.

Turns out to be able to cool the whole room just fine, using a floor fan to move the air around.

I have never heard this advice before and do not understand it. In fact, at night, if you use the aircon, you are advised to set it above 26.

Expect it was just a Thai-English miss-communication (happens all the time)...they were probably trying to point out something else regarding its operation in relation to temperature. The higher temperature you run will save you money as the A/C's compressor will run less and the compressor is the energy hog.

Have you tried googling the A/C part number as you should be able to come up with an English language manual online somewhere...or a manual for a very similar model.

You can run the ac at what ever temp is comfortable to you, i ajust mine to the season. Right now i run at about 24 at night for noise and humidity. During the hot season sometime 27 or 26. I have 40 sqm and 18,000 but seems a little week all the way over to the bathroom. Adjust the fan up and down also.

I think you would be better to turn the fans off and just use the AC. Keeping the humidity lower is the key to comfort.

Perhaps the "no good" was for the first on testing they were doing? They would want it at low enough temp to run the compressor after cleaning and this time of the year that might require 23/24 setting.

Thanks for the suggestions. I'll just run it at the most comfortable temp and use floor fans to move the air around.