how to compute the rating of airconditioning unit based on the volume of the room?

Question

what is the rating of airconditioning unit rating in HP? for instance you are going to install an airconditioning unit in your bedroom, but you dont know the rating of fit aircondition to be installed.may if its undersize or oversize in horse power.

Answer 1

Air conditioners are rated in BTU/hour of cooling capacity. Central AC units may also labeled in "tons" where 12,000 BTU/hour = 1 ton of cooling capacity.

The cooling capacity you need is based on the volume of the room, but is also affected by the number of windows (solar heat gain) and whether the walls are exterior walls, or are adjacent to another apartment/condo.

A reasonable "rule of thumb" is 12,000 BTU/hour for every 600 ft².

If you're looking to cool just one typical bedroom, a 5000 to 6500 BTU/hour unit is probably fine.

Answer 2

Basically, you don't consider volume, you consider outside wall area, exposure, and windows.
These are used to give you the heat 'gain`.
For a normal bedroom with two outside walls 7500 BTU/Hr. is probably about right. (Rough guess).