Solar Heat Gain Calculator

Calculate solar heat gain through windows based on SHGC, orientation, latitude, and shading to estimate cooling load impact.

Window Area

sq ft

Solar Heat Gain Coefficient

Orientation

Latitude

Shading Coefficient

Tab to move between fields

Peak Solar Gain

1,500 BTU/hr

Annual Heat Gain

3,000,000 BTU

Cooling Load1,500 BTU/hr

Shading Reduction75%

How to Use This Calculator

Enter the total Window Area in sq ft for the facade being analyzed.
Enter the SHGC (Solar Heat Gain Coefficient) from the window label (0 = no gain, 1 = full gain).
Select the Orientation (north, south, east, or west) and enter your Latitude.
Enter the Shading Coefficient to account for overhangs, fins, or blinds reducing solar exposure.
Review Peak Solar Gain and Cooling Load Contribution in BTU/hr and Annual Heat Gain in BTU.

How the result changes with Window Area

Window Area: Total glass area of windows on this facade.
Solar Heat Gain Coefficient: SHGC rating from window label (0 to 1, lower = less heat gain).
Orientation: Compass direction the windows face; south gets most winter sun.
Latitude: Location latitude (affects sun angle and solar intensity).
Shading Coefficient: External shading factor (1.0 = no shading, 0.5 = 50% shaded).

Identify Input Parameters
4 parameters
Window Area = 30, Solar Heat Gain Coefficient = 0.25, Orientation = 2, Latitude = 40 = 5 input(s) provided
Calculate Peak Solar Gain
Peak Solar Gain
1500 = 1500
Calculate Annual Heat Gain
Annual Heat Gain
3000000 = 3000000
Calculate Cooling Load
Cooling Load
1500 = 1500
Calculate Shading Reduction
Shading Reduction
75 = 75

Engine last updated July 22, 2026. Checked against 2 independently-derived tests — how we verify calculators.

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