Free Heat Gain Calculator
Estimate summer cooling load (heat gain) for a space based on area, solar exposure, and internal heat sources.
sq ft
BTU/sqft
people
W
Total Heat Gain
50,812 BTU/hr
Cooling Tons4.2 tons
Envelope Component45,000 BTU/hr
Total Heat Gain vs Floor Area
Cooling Load (Heat Gain)
Total = Envelope Gain + People Gain + Appliance Gain
Envelope gain uses a factor of 20 to 40 BTU per sq ft depending on climate and insulation. Each person adds about 600 BTU/hr. Appliances convert at 3.412 BTU per watt. One ton of cooling = 12,000 BTU/hr.
Example Calculation
1,500 sq ft, 30 BTU/sqft factor, 4 people, 1000W appliances.
- 01Envelope = 1500 x 30 = 45,000 BTU/hr
- 02People = 4 x 600 = 2,400 BTU/hr
- 03Appliances = 1000 x 3.412 = 3,412 BTU/hr
- 04Total = 50,812 BTU/hr = 4.2 tons
Frequently Asked Questions
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