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What should I consider for when buying a room air conditioner?
Remember that bigger is not always better! Buying an air conditioner that is too large does not provide better cooling. An oversized air conditioner is actually less effective — and wastes energy at the same time. Make sure your unit is properly sized.
Properly Sized Room Air Conditioners
Room air conditioner sizing is all about matching the room size to the air conditioner size. A unit that is too big will be less effective and
offer reduced air conditioner efficiency. Air conditioners remove both heat and humidity from the air. If the unit is too large, it will cool the
room, before it has a chance to remove the humidity. The result will be a room that's not very comfortable to spend time in. That cool moist air
will make the room feel damp and clammy.
The most energy efficient air conditioner is sized to the square footage of the space to be cooled. Getting the right size means getting the comfort and the energy efficiency right.
How to properly size a room air conditioner.
1. Determine the room's square footage
9 in = .75 ft.
6 in = .5 ft.
3 in = .25 ft.
Always measure in feet, converting the inches to fractions of a foot
For example: 12 ft., 6 inches, is 12.5 ft.
Square and rectangular rooms:
Triangular rooms:
Complex room shapes:
If the shape of your room is more complex, ask your sales associate where you plan to purchase your air conditioner to help you determine the square footage.
2. Find the correct cooling capacity for your room size
With the cooling capacity chart, find your room's square footage in the "Area To be Cooled (square feet)" column, then use the "Capacity Needed (BTUs per hour)" column to choose the correct cooling capacity for your room air conditioner. Cooling capacity is shown in British thermal units (BTUs) per hour.
| Area To Be Cooled (square feet) | Capacity Needed (BTUs per hour) |
|---|---|
| 100 up to 150 | 5,000 |
| 150 up to 250 | 6,000 |
| 250 up to 300 | 7,000 |
| 300 up to 350 | 8,000 |
| 350 up to 400 | 9,000 |
| 400 up to 450 | 10,000 |
| 450 up to 550 | 12,000 |
| 550 up to 700 | 14,000 |
| 700 up to 1,000 | 18,000 |
| 1,000 up to 1,200 | 21,000 |
| 1,200 up to 1,400 | 23,000 |
| 1,400 up to 1,500 | 24,000 |
| 1,500 up to 2,000 | 30,000 |
| 2,000 up to 2,500 | 34,00 |
3. Adjust as necessary
Make any adjustments for the following circumstances:
If the room is heavily shaded, reduce capacity by 10 percent.
If the room is very sunny, increase capacity by 10 percent.
If more than two people regularly occupy the room, add 600 BTUs for each additional person.
If the unit is used in a kitchen, increase capacity by 4,000 BTUs.
Consider where you install the unit. If you are mounting an air conditioner near the corner of a room, look for a unit that can send the airflow in the right direction.
