Lighting Considerations in Green Building

10/24/2007 by Paul Price

Lighting uses between 20%–25% of electricity in the U.S.—5%–10% of it in households, and 20%–30% in commercial facilities. In most of these buildings, at least 50% of this energy is wasted because of inefficient fixtures or equipment, poor maintenance, or inappropriate use.

One of the best ways to understand your lighting requirements is using the IES guidelines (Illuminating Engineers Society). As part of lighting design they are encouraging engineers to run a photometric analysis of the design before it is built. In many cases the light level may be higher or lower than what was expected. This allows modifications to the design to meet the ideal light level. Many design changes are as simple as changing the selection of lamps and ballasts.

There are several approaches to saving energy expended on lighting. They include:

Both the IES (Illuminating Engineering Society) and ASHRAE advocate for proper lighting power density calculations to provide adequate light for the type of space and not “over lighting.” Lighting design just 10 years ago averaged 2 watts per square foot; current technology and design can provide the proper light evenly displaced at less than 1 watt per square foot. There are three key design components:

This article is an excerpt from the book Green Building: Project Planning & Estimating which can be purchased through the RSMeans Bookstore.

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