Heat Gain Calculator — Calculate Heat Load & Cooling Requirements

Heat Gain Calculator

Calculate heat gain in buildings and spaces. Determine cooling requirements based on insulation, windows, occupancy, equipment, and environmental factors.

Step 1: Space & Building

1,000
100

Understanding Insulation

Higher R-values indicate better insulation performance. Better insulation reduces heat transfer, lowering cooling requirements and energy costs.

Step 2: Heat Sources & Climate

5
1,500
800
95°F
72°F

About Heat Gain Sources

Heat gain comes from conduction through walls/roof, solar radiation through windows, occupants, lighting, and equipment. Each contributes to the total cooling load.

Heat Gain Analysis Results

Summary
Insulation Comparison
Breakdown

Total Heat Gain

8,450 BTU/h
Equivalent to 0.7 tons of cooling capacity
Cooling Capacity Needed
0.7 tons
Conduction Heat Gain
3,240 BTU/h
Solar Heat Gain
2,150 BTU/h
Internal Heat Gain
3,060 BTU/h

Insulation Level Comparison

Insulation Level R-Value Heat Gain (BTU/h) Cooling Tons

Heat Gain by Source

Heat Gain Formula

Total Heat Gain = Conduction + Solar + Internal Heat

Conduction heat gain through walls/roof: Area × ΔT × U-value
Solar heat gain through windows: Window Area × SHGC × Solar Factor
Internal heat: Occupants + Equipment + Lighting

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