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AC/BTU Room-Size Estimator

Estimate cooling capacity from room area and simple occupancy adjustments.

Your inputs

Your result

Enter your information and select Calculate to see the result.

How this calculator works

The estimate uses 20 BTU/hour per square foot plus 600 BTU/hour for each person beyond two.

Change one assumption at a time to see which inputs have the greatest effect on the estimate.

Worked example

A 12 ft by 15 ft room with two people estimates to 3,600 BTU/hour.

Limitations

Sun exposure, insulation, ceiling height, appliances, humidity, climate, and whole-home airflow can change sizing substantially. Have HVAC equipment sized using an appropriate load calculation.

Review this educational estimate against current quotes, official information, and your own budget before making a financial decision.