Lighting Heat Gain Calculator

Calculate heat gain from lighting systems including fluorescent, LED, and incandescent fixtures.

Conditioned floor area.
ft²
Watts per square foot (0.5-1.5 typical, ASHRAE 90.1 limits).
W/ft²
Multiplier for ballast heat (1.0 for LED, 1.2 for fluorescent).
Fraction of lights on during peak (0.5-1.0).
Fraction of heat to conditioned space (0.6-1.0).

Results

Total Lighting Power-watts
Heat Gain to Space-BTU/hr
Cooling Load-tons
Actual LPD-W/ft²
References: ASHRAE Fundamentals Chapter 18: Nonresidential Cooling and Heating Load Calculations; ASHRAE Standard 90.1 Section 9: Lighting