Typical BTU Cooling Capacity Range for Air Conditioners

Portable, window, or through-wall air conditioners are typically described by their manufacturer as suited for

Single Room Air Conditioner Capacity - typically for rooms up to 20' x 20' or 400 sq.ft. in area. BTUs in this product range are typically from 6,000 BTUh to 10,000 BTUh.


Multiple Room Air Conditioner Capacity - typically for a total area of up to 800 sq.ft. BTUs in this product range are typically from 10,000 BTUh to 16,000 BTUh.

Large Capacity Air Conditioner Capacity - typically for multiple rooms or very large rooms up to a total area from 900 sq. ft. to 2,000 sq.ft. BTUs in this product range are typically from 16,000 to 28,000 BTUh.

Central Air Conditioning - typically to cool an entire floor or multiple floors in a home.
 
To determine the BTUs needed to cool a given space follow this procedure:
 
1.    Calculate the total square feet to be cooled: Measure the size of the room (or rooms) to be cooled, to obtain total square feet. Multiply room length by width for each room and if there are multiple rooms, add the room areas together to get a single number.
 
2.    Read the Base BTUs needed from Table 1 below
 
3.   Add additional BTUs for these factors:
 
4,000 BTUs for each room below a ceiling or roof which is not insulated


+ 4,000 BTUs for a home or residential kitchen included in the cooled area

+ 1,500 BTUs for each window which receives significant daily sunshine

+ 1,500 BTUs for a room over a kitchen or boiler room IF the kitchen or boiler room is actively producing heat during the cooling period

+ 600 BTUs per person over two, if more than two occupants will be occupying the room during the cooling period

4.      Subtract BTUs from the total required if these factors are present:

- 1,000 BTUs if the room is on the shaded side of the building


5.     Calculate the final total BTUh needed from the above steps. This should place you in the right range of cooling capacity needed. Review the warning below about buying an oversized air conditioner.
 
The table below gives recommended air conditioning BTU's necessary to cool a single room. The data in the table assumes that the ceiling over the room is insulated and that the room is not over or is not itself a special heat-producing area such as a kitchen or boiler room.
 

To cool this area, look for this size air conditioner

 

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