Air conditioner BTU calculator

Find the AC capacity (BTU/h) a room needs.

How it works

The estimate uses the widely cited U.S. Department of Energy rule of about 20 BTU/h per square foot, adjusted for ceiling height, sun exposure, occupants and kitchens.

How to measure

Measure the floor area and ceiling height. Count open-plan spaces as one room.

Tips

An oversized unit short-cycles and removes humidity poorly.
Inverter units run more efficiently at part load.
For an exact size, ask an HVAC contractor for a Manual J calculation.

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