Lighting Power Density (LPD) & Energy Code Calculator
Calculate Lighting Power Density (Watts/ft² or Watts/m²) and verify compliance against ASHRAE Standard 90.1 and California Title 24 building energy efficiency standards.
Cubicles, collaborative workstations, shared computer desks.
About Lighting Power Density (LPD) Standards
Lighting Power Density (LPD) is the maximum permitted electrical power density consumed by interior lights per unit of floor space. ASHRAE 90.1 and Title 24 establish mandatory maximum limits to minimize carbon emissions and reduce peak utility grid demand.
Building Area Method vs Space-by-Space Method
The Space-by-Space Method calculates maximum allowable wattage by breaking a facility down into individual rooms (e.g. private offices, open areas, restrooms, corridors). This allows spaces needing higher illumination to utilize appropriate wattage while maintaining an aggressive overall efficiency profile.
Why Modern LED Design Crushes Energy Codes
With modern LED efficacies exceeding 120–160 lumens per watt (lm/W), contemporary lighting designers routinely achieve 300–400 lux desk illumination with Lighting Power Densities under 0.35 to 0.45 W/ft² — leaving substantial compliance margins below the 0.61 W/ft² ASHRAE 90.1 ceiling.