Keep your home cool without wasting energy with our guide to air conditioner sizes.

This does not refer to the physical size of the unit.

Rather, air conditioner size is a measurement of the cooling capacity, which is typically represented in BTU.

air conditioner hvac outside brick wall

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BTU (British Thermal Unit)is used to measure energy.

However, this rating can also be stated in tonnage, with 12,000 BTUh equal to one ton.

Start bymeasuring the square footage.

Window air conditioning unit installed in window

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The result, as shown in this chart, is 40,000 BTUs.

The square footage to BTU calculation rate is the same for HVAC and window units.

Department of Energy, “ENERGY STAR qualified central air conditioners must have a SEER of at least 14. https://www.energy.gov/energysaver/room-air-conditioners

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Window air conditioning unit installed in window

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