A comprehensive source for understanding the lighting models underlying the commercial lighting power limits developed in ASHRAE/IESNA 90.1-2004.

Energy standards behind Lighting Power Density.
Glossary of LPD Terms.

Public Discussion about Lighting Power Densities.

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Explore lighting power density models for entire buildings.
Whole Building LPD

Explore lighting power density models for individual spaces.
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The IESNA Energy Management Committee (EMC), working with the Lighting Subcommittee of the ASHRAE/IESNA 90.1-2004 Standing Standards Project Committee (SSPC) has developed an interactive methodology for determining lighting power densities for both individual spaces and whole buildings. This methodology is the basis for the lighting power density numbers found in the ASHRAE/IESNA 90.1-2004 Standard.

This methodology calculates lighting power allowances for building spaces and whole buildings. The process models lighting design assumptions from a consensus of lighting design professionals for each of the space types used in 90.1-2004, using currently available efficient lamp/ballast/fixture data, and illuminance values from current IESNA illuminance recommendations. In this way, the needs of the occupants are taken into account and energy-efficient design is promoted through the resulting lighting power densities.

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