Lighting Controls

Lighting controls help to make commercial buildings more comfortable, productive, and energy efficient. These controls can turn lights off when they are not needed or dim them so that no more light than necessary is produced. The two functions can be employed individually or, to provide even greater benefits, in tandem. The equipment used to achieve these functions ranges from simple timers to intricate electronic dimming circuits.

A well-designed control system will provide the right amount of light where and when it’s needed, and it will cut lighting energy use by 5 to 60 percent, depending on the baseline conditions and the control strategies used. A meta-study performed by Lawrence Berkeley National Laboratory (LBNL) reviewed 240 savings cases described in 88 papers and case studies (Table 1) and summarized the average savings achieved from all major control types.

Table 1: Energy savings from lighting controls
A variety of strategies are available to cut lighting energy use. A Lawrence Berkeley National Laboratory meta-study reported on the average savings found for a set of strategies, and manufacturers provide typical ranges.

In addition, lighting controls enable end users to participate in utility demand-response programs, and advanced lighting control systems can also improve maintenance by signaling lamp outages and monitoring output levels to indicate when they fall below required or desired levels.

Most of the studies reported on by LBNL covered fluorescent lighting. LEDs offer the potential for even higher percentage savings for several reasons. However, the total savings may not be as high because with LEDs in place, you may be starting from a lower power level to begin with.

Instant response, no cycling effect. LEDs respond instantly, and their lamp life is not shortened by frequent switching. Fluorescent lamp life decreases the more frequently the lamps are cycled on and off; high-intensity discharge (HID) lamps have a long delay time on start-up and restrike.

Dimming capability. LEDs can be dimmable, but care has to be taken to ensure that they’re compatible with the dimming controls employed. For some products, dimming can lengthen the life of LEDs because they run cooler when dimmed.

Color controllability. Good-quality LEDs can maintain a constant color temperature as they dim;, and controls can be used to change the color temperature of LED lighting, a feature that’s being used in a growing number of products to mimic the dimming behavior of incandescent lamps. Color-changing can also be used to support applications that are evolving out of a growing body of evidence that color temperature can play an important role in improving human health and productivity.

When LEDs and controls are combined in an installation, the savings can be dramatic. A Sacramento Municipal Utility District program found lighting energy savings of 50 to 90 percent in more than a dozen projects. About 60 percent of savings were from the light-source upgrade and 40 percent from the addition of controls.

What are the options?
How to make the best choice
What’s on the horizon?
Who are the manufacturers?
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