HVAC Cooling Load Estimator
Estimate a room's cooling load (BTU/hr and tons) from area, occupants, lighting, equipment and climate.
Inputs
Results
Envelope load12,360BTU/hr
Window / solar6,000BTU/hr
Occupants1,600BTU/hr
Lighting + equipment2,728BTU/hr
Total cooling load22,688BTU/hr
Tons of refrigeration1.89TR
Cooling load6.65kW
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Formula
Q_total = Q_envelope + Q_solar + Q_people + Q_lights + Q_equip. Tons = BTU/hr ÷ 12,000.
Worked example
400 ft², 9 ft ceiling, 4 people, 40 ft² south windows, hot climate → ~18,500 BTU/hr ≈ 1.5 tons.
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Frequently asked questions
Can I use this to size a residential AC?
For a first pass, yes. For an actual installation quote, insist on a Manual J calculation — oversized ACs short-cycle and dehumidify poorly.
Why does ceiling height matter?
Higher ceilings mean more air volume, more envelope area, and typically more stratification — 3% per foot above 8 ft is a common adder.
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