How to Figure Correct Size for Air Conditioners

Get the right sized air conditioner.

Getting the right air conditioner for your room can save you money on your purchase and also on your electric bill. According to Energy Star, a branch of the United States Environmental Protection Agency, a bigger air conditioner will not necessarily cool your home more efficiently. Use the square footage of the area to be cooled to figure out the right size for your air conditioner. The U. S. Department of Energy says that you need about 20 Btu for each square foot you are cooling.

Things You'll Need

• Tape measure
• Calculator

Instructions

1. Measure the length and width of the area you are cooling with the tape measure.

2. Multiply the length by the width to get the area. If your room is 15 feet by 20 feet, then the area is 300 square feet.

3. Multiply the square footage by 20 to get the number of Btu you will need to cool the space. In this instance, a space of 300 square feet would take a 6,000 Btu air conditioner.

4. If your space is shaded by trees or other structures, you can deduct 10 percent of the Btu from your calculation. Likewise, if it gets a lot of direct sun, add 10 percent to the total.

References

• US Dept. of Energy: Heating and Cooling
• Energy Star: Properly Sized Air Conditioners