Lighting Overview

For many years, the most common means of lighting our homes has been the incandescent lamp or light bulb. Incandescent lamps are inexpensive, provide excellent color rendition and give off a warm, pleasing light. Unfortunately, they are also very inefficient. Only a relatively small portion of the electricity used is actually converted to light - the remainder is given off as heat (this heat is the primary reason why light bulbs fail or "burn out"). While lighting your home may account for only 5 to 10% of your total energy use, the excess heat produced by incandescent lamps can increase your air conditioning costs, wasting even more of your energy dollars.

Lighting your home more efficiently may involve changing the way you use lighting, or the amount of lighting you use. It can also mean changing the types of lighting in your home.

Lighting Types

Incandescent Lamps

These are the most common and least expensive type of lamp, but are also the least efficient and most costly to operate. If you need to use incandescent lamps, look for the "long life" or "Energy Saver" type - they produce slightly less heat (which accounts for the longer life) and more light for the amount of electricity used.

Halogen Lamps

These are a type of incandescent lamp. They have a longer life than conventional light bulbs, but they are only slightly more efficient. Some halogen lamps have very high wattage, which increases both the intensity of the light and the amount of heat given off. Halogen torchiere fixtures can get extremely hot and have been implicated in many fires. These fixtures must be kept away from curtains and other flammable materials. Halogen lamps are best suited for lighting areas where a direct focus of light is required, and are not recommended for general area lighting.

Linear Fluorescent Tubes

These lamps are the most common source of lighting in commercial facilities and can be found in many homes as well. They are much more efficient than incandescent lamps and produce a bright white light. They are well suited for areas like kitchens, garages and work areas, but require a different type of fixture and cannot be interchanged with incandescent lamps. For home use, lamps and fixtures are available in sizes ranging from 2 feet to 5 feet in length.

Compact Fluorescent Lamps (CFLs)

These lamps use the same technology as linear tubes, but are designed to take the place of incandescent lamps. They incorporate a ballast and a screw base adapter to accommodate their use in many indoor and outdoor fixtures. Although CFLs are more expensive than standard light bulbs, they use only one quarter of the electricity and can last more than 10 times as long as an incandescent. In the long term, taking into account replacement costs, they are a much more economical option than incandescents.

LED (Light Emitting Diode)

LEDs are tiny, solid light bulbs that are extremely energy-efficient. An LED uses about one-third the energy as a compact fluorescent and lasts up to ten times as long, as it generates almost no heat. In the past, the use of LEDs has been limited mainly to instrument panels and electronics. Manufacturers have expanded their applications by grouping the bulbs in clusters with diffuser lenses that spread the light in a wider pattern. There are now versions with standard bases to fit most typical residential light fixtures. The primary obstacle to wider use has been the high initial cost. Recent breakthroughs in manufacturing should lower costs significantly, and some experts predict that LEDs will become the "light of the future".

The Sun

An excellent light source. A small amount can provide enough light for an entire room and can be the equivalent of dozens of incandescent lamps. It's also environmentally friendly and free.

Lighting Comparison

Type Incandescent Halogen Linear Tube CFL LED
Efficiency Poor Poor Good Good Excellent
Cost Low Moderate Moderate Moderate High
Estimated Lifetime 750-2500 hours 2,000 - 4000 hours 7,000 - 24,000 hours 10,000 - 12,000 hours 25,000 hours or more

General Tips

  • There's no better source of light than natural daylight. In summer, try to take advantage of light from the north side or through windows shaded from direct sunlight - indirect sunlight is cooler and won't heat up the home. Light colored interiors can help you make the most of natural daylight (and other lighting as well).
  • Turn off the lights when not in use. Make it a habit to turn off the light when you leave a room. Consider installing occupancy sensors, which automatically turn lights out when no one is in the room. Timers can be useful when you're out for the evening or on vacation. Use motion sensors on outdoor security lights.
  • Use incandescent lights sparingly. It takes two 60-Watt bulbs or four 40-Watt bulbs to provide the same amount of light as one 100-Watt bulb. Also, use the minimum wattage necessary. Consider using dimmers in areas where full lighting is not always required.
  • Use "task" lighting to focus light right where it's needed. Turn off ceiling lights or area lighting and use table lamps, track lighting, or under counter lights instead.
  • For outdoor lighting, use compact fluorescent floodlights, metal halide, or high-pressure sodium lamps. High-pressure sodium lamps use 70% less energy than a standard floodlight and last up to eight times as long. Use photocells to keep the lights off in daytime, combined with motion detectors that turn on the lights only when movement is sensed.

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