AC Size (BTU) Calculator
Estimate room cooling capacity from area and an adjustable cooling-load rate.
Estimate room cooling capacity from area and an adjustable cooling-load rate.
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Open calculatorEstimate room cooling capacity from area and an adjustable cooling-load rate.
The AC BTU calculator provides a simple area-based cooling-capacity estimate. It multiplies room area by an editable cooling-load rate in BTU per hour per square meter and also expresses the result in refrigeration tons.
Enter the room or conditioned area in square meters and the cooling-load rate you want to assume in BTU/h per m². The calculator multiplies the two values to obtain BTU/h, then divides by 12,000 to express the same capacity in refrigeration tons.
The cooling-load rate is editable; the calculator defaults to 600 BTU/h per m². This default is a calculation assumption, not a universal sizing rule. The simplified formula does not independently model climate, solar gain, wall and roof insulation, glazing, orientation, ceiling height, occupants, appliances, ventilation or infiltration.
For 20 m² using an entered rate of 600 BTU/h per m², capacity = 20 × 600 = 12,000 BTU/h, equivalent to 1.00 refrigeration ton.
Use the result for preliminary comparison only. Final air-conditioning selection should consider the actual building envelope, climate, occupancy, ventilation and manufacturer or HVAC-design requirements.
No. It is the calculator's editable default assumption. Actual cooling loads vary significantly with building and climate conditions.
The calculator uses 12,000 BTU/h per refrigeration ton when expressing the calculated cooling capacity in tons.
No. It is a simplified area-rate estimate and does not model the full set of heat gains and building characteristics required for detailed equipment sizing.
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