Saving Energy With Outdoor Lighting

Many homeowners use outdoor lighting for security and to enhance the appearance of their homes. Unfortunately, these lights are often left on all night, wasting a great deal of energy. Security or area lighting often uses high-wattage lamps, which, combined with long hours of operation, can significantly increase electric usage. For example, a 250W floodlight that's left on for 12 hours a day will use 90 kilowatt-hours of electricity in a month.

In addition to wasting energy, overuse of outdoor lighting also contributes to light pollution, a growing concern among scientists and medical professionals. Excess nighttime illumination can affect behavioral patterns of wildlife, including mating and migratory activities. Medical research has shown that altering the natural light/dark cycle can adversely affect human health as well. Outdoor lighting can serve useful purposes, but should be used only when and where it is needed. Avoid illuminating large areas or directing the light where it isn't needed.

Area and Security Lighting

The best ways to save energy with outdoor area or security lighting are to use energy efficient lamps and to control them effectively.

Compact fluorescents are available as flood lamps - ones rated for outdoor use are designed to withstand weather so they can be used in exposed fixtures (in cold climates, look for ones rated for low temperature use). For optimum control, be sure to look for ones rated for use with motion sensors.

High intensity discharge or HID lamps are also much more efficient than incandescent floodlights. They are commonly used for streetlights and lighting large areas like parking lots. Options include high-pressure sodium, mercury vapor or metal halide. Look for shielded fixtures that direct the light only where needed.

Control options include photocells, timers and motion sensors. Photocells that turn off the lights in daytime can be purchased with new fixtures or as an add-on for existing fixtures. Outdoor timers are encased in a watertight metal enclosure to protect them from the elements, and are sometimes combined with photocells. In many cases, the best option is a combination of a photocell to keep the light off in daytime and a motion sensor to turn it on when movement is detected. For security purposes, a light that suddenly turns on is probably more effective than a light that stays on (and can simply be avoided).

Porch and Pathway Lighting

Standard compact fluorescents work well as porch or pathway lights in enclosed fixtures that protect them from weather. Others have a protective casing and are designed for use in exposed fixtures. In cold climates look for ones rated for low temperatures. Consider installing a photocell or timer so the light doesn't stay on in daytime.

Decorative and Landscape Lighting

Low-voltage lighting is a good option for decorative and landscape lighting. Low-voltage light kits contain a power pack, cables and lamps. They usually use either halogen or LED lamps. LEDs are well suited for outdoor use and use less energy than halogens. Some kits incorporate a built-in timer.

In terms of energy savings, the best option is solar. Solar powered outdoor lighting uses photocells to convert sunlight into electricity. They need no wires or cables- simply stick them in the ground where it's sunny and let them charge up (it may take them several days of charging to reach their maximum light output).

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