I have a room with good windows it is about 800 sg ft any suggestions as to size of A / C?

It is in the ground floor so sunlight does not come in to this level.

I was at home pro and they quoted me an A/C at 26000 btus and I think it is a little over sized

Thanks in advance

Look at the chart provided by the company that makes the unit - they have a formula depends on height of wall etc. You can find one online also.

How much is that in sqm?

Approx 75 sq m.

How high, what are the walls made of, ceiling insulation. ? eg for a 3 inch cinder block wall and un insulated roof and inside temp 20 C , 26K would be way too low. (imho)

Impossible to guess without further info. Note, if you use on line calculator from US, UK etc it could well be based on a much lower temperature differential and therefore give a wrong figure.

With such a big space I suggest that you're outside the realms of the simple calculators (comes out at 45,000 BTU). I suggest enlisting the help of a professional aircon supply company.

Good luck in your quest

There are other considerations beyond just room size. The layout of the room determines no. of aircon units to give better airflow, else you get hot and cold spots. Any air or stair well, opening to kitchen, etc which causes leakage of cooled air.

Thailand is strange. No insulation to speak of. Just a electric money pit.

If insulated properly 24000 BTU would be over kill. Here?

Many calculators available on internet, Google with "air con size calculation". For example, http://www.panasonic.com.au/Products/Air+conditioners/Sizing+Wizard

That one has very much flexibility re room size, shape, shape adjustment.

With normal thai "insulation" or the lack thereof, 1000 BTU per sqm.

I think you'd be better off talking to a cooling specialist tho, since the volume of the room differs from building to building.

Edited July 1, 201313 yr by Chamezz

I have 65 sq/m (interior space) single room, 10' ceilings, rooms below and above me, 30 sq/ft of un-insulated window on the sunny side which is a 3" thick lengthwise wall that gets hot when exposed to the sun in the AM. I use an older (10 year) 24,000 BTU unit and move air around by fan. I keep temp at 27 degrees and run about 16 hours a day hot season, less at cooler times. Hot season bills (Bt 3/unit) run B4000-4500. Rainy and cooler season run B2500-B3000

I have been told that a 30,000 BTU unit would be more efficient but it would take years to pay for itself and make a change worthwhile