Air Con Size Chart

[wpcoe]

I found this chart on a Thai web site (www.ruamair.com) and was wondering if somebody could translate the column headings, especially in the first chart. I assume they relate to directional exposure, etc, but it would be nice to find out.

(Click here for a larger version. I was afraid to post it inside the message for fear of being too big, but the Thai script is more legible.)

Thanks!

[Tywais]

1st column after BTU - bed room

2nd column - bed room with sun exposure

3rd column - guest room (actually receive guests, so maybe living room)

4th column - same but sun exposure

5th column - work room

6th column - work room with sun exposure

There are so many other variables involved that this table is not a very good guideline.

[Nawtilus]

Easiest way to get the BTU required for a room is to mulitply the rooms square meters by 700. This will give you the btu required, then if the room has some abnormal apliances or is in the sun etc, just bump the aircon size up to the next size available above what the x 700 method tells you.

[Naam]

Easiest way to get the BTU required for a room is to mulitply the rooms square meters by 700. This will give you the btu required, then if the room has some abnormal apliances or is in the sun etc, just bump the aircon size up to the next size available above what the x 700 method tells you.

[Tywais]

A couple of sites use this info, need to convert to metric if necessary.

100 to 150 square feet - 5,000 BTUs

150 to 250 square feet - 6,000 BTUs

250 to 300 square feet - 7,000 BTUs

300 to 350 square feet - 8,000 BTUs

350 to 400 square feet - 9,000 BTUs

400 to 450 square feet - 10,000 BTUs

450 to 550 square feet - 12,000 BTUs

550 to 700 square feet - 14,000 BTUs

700 to 1,000 square feet - 18,000 BTUs

1,000 to 1 400 square feet - 24,000 BTUs

That’ll give you a ball-park figure for the BTUs you’re looking for. But wait, we’re not done! There are some variables to take into account:

* If the room is heavily shaded, you can reduce the BTU capacity by 10%

* If the room is very sunny, you should increase the BTU capacity by 10%

* If more than 2 people regularly occupy the room, add 600 Btu for

each additional person

* If the unit is for a kitchen, increase the capacity by 4,000 BTUs.

[wpcoe]

1st column after BTU - bed room

2nd column - bed room with sun exposure

3rd column - guest room (actually receive guests, so maybe living room)

4th column - same but sun exposure

5th column - work room

6th column - work room with sun exposure

There are so many other variables involved that this table is not a very good guideline.

Thanks so much for the interpretation! I realize there are lots of variables, such as room height, if on top floor with uninsulated attic, amout of window glass, etc, but it sounds reasonable for a starting point.

[wpcoe]

100 to 150 square feet - 5,000 BTUs

150 to 250 square feet - 6,000 BTUs

250 to 300 square feet - 7,000 BTUs

300 to 350 square feet - 8,000 BTUs

350 to 400 square feet - 9,000 BTUs

400 to 450 square feet - 10,000 BTUs

450 to 550 square feet - 12,000 BTUs

550 to 700 square feet - 14,000 BTUs

700 to 1,000 square feet - 18,000 BTUs

1,000 to 1 400 square feet - 24,000 BTUs

Hmmm. Those sound awfully optimistic, especially for the tropics. 12,000 BTU to cool 500 sq ft (46 sq meters)? That doesn't sound realistic.

In a townhouse I rented in Bangkok, I put a 13,500 BTU unit in a bedroom about 23 sq meter, and during the daytime it could never get the room below 28 degrees ( C ). That chart says for a room twice that size the base calculation should be 12,000 BTU? I wonder....

[Tywais]

In a townhouse I rented in Bangkok, I put a 13,500 BTU unit in a bedroom about 23 sq meter, and during the daytime it could never get the room below 28 degrees ( C ). That chart says for a room twice that size the base calculation should be 12,000 BTU? I wonder....

Possibly the a/c in the townhouse had problems (dirty, freon, etc.) I have a 12,000 BTU in my computer room (got it cheap, why so large) and it is also about 23 sq meter. My room temperature right now is 22.5 degrees and that is set on level 3 out of 7, a 7 and I would need winter arctic gear.

In my bedroom I have 9000 BTU and it is about 40 sq meter and keeps it at temperature with no problem.

[wpcoe]

In a townhouse I rented in Bangkok, I put a 13,500 BTU unit in a bedroom about 23 sq meter, and during the daytime it could never get the room below 28 degrees ( C ). That chart says for a room twice that size the base calculation should be 12,000 BTU? I wonder....

Possibly the a/c in the townhouse had problems (dirty, freon, etc.) I have a 12,000 BTU in my computer room (got it cheap, why so large) and it is also about 23 sq meter. My room temperature right now is 22.5 degrees and that is set on level 3 out of 7, a 7 and I would need winter arctic gear.

In my bedroom I have 9000 BTU and it is about 40 sq meter and keeps it at temperature with no problem.

I bought the 13,500 unit new, and had it cleaned/serviced several times over the years by an independent guy who said there was nothing wrong with the unit. He asked me why I bought such a small unit. <shrug>

I just noticed that my Thai chart for a bedroom of 23sq.m recommends 15,300 BTU (or 15,300 or 18,000 BTU if sunny). That is more consistent with my (sunny) townhouse bedroom, while your computer room is consistent with the chart you posted. Interesting! (Is your computer in a bat cave? )

And, yes, 22.5 degrees is downright CHILLY!

[tutsiwarrior]

any advice regarding A/C and sizing application that pays no attention to materials, insulation and the associated thermal conductivities is rubbish...in this case sounds like sum A/C vendor that saw sum rube was coming (with respect)...

there are more simple and accurate ways of determining your A/C load and choosing the necessary equipment based upon the desired indoor temperature...google on ASHRAE and on Carrier to find the best solution...

all the best...tutsi

[Naam]

any advice regarding A/C and sizing application that pays no attention to materials, insulation and the associated thermal conductivities is rubbish...in this case sounds like sum A/C vendor that saw sum rube was coming (with respect)...

there are more simple and accurate ways of determining your A/C load and choosing the necessary equipment based upon the desired indoor temperature...google on ASHRAE and on Carrier to find the best solution...

all the best...tutsi

[Moonfruit]

Each room is unique in its cooling requirements, depending on how many people will be occupying, whether it gets any sun, whether you run any electiral appliances etc etc.

Check out this link for an accurate formule for calculating the BTU needed for your room.

http://www.ryanairconspares.com/informatio...&info_id=17

[wpcoe]

Check out this link for an accurate formule for calculating the BTU needed for your room.

http://www.ryanairconspares.com/informatio...&info_id=17

I got a little chuckle on that site. They validly advise you to factor in many causes of heat gain and/or cooling loss, but for the windows section all they say is:

If, your room has no windows, you can ignore this part of the calculation. If, however there are windows you need to take the size and orientation into account.

South Window BTU = South Facing window Length (m) x Width (m) x 870

North Window BTU = North Facing windows Length (m) x Width (m) x 165

If there are no blinds on the windows multiply the result(s) by 1.5.

Add together all the BTUs for the windows.

As if east- and west-facing glass has no effect?

Thanks to all who have contributed. I've worked with air con BTU calculations before in another climate/latitude and wasn't sure what to use for a base calculation here in the tropics.