What You'll Learn

  1. Introduction
  2. Lamps
  3. Fixtures
The most common screw-in incandescent lamp is cheapest to buy, but can be much more expensive to operate in the long run, compared to a more efficient lamp with the equivalent lumen output. An incandescent providing comfortably warm 2700K, 100 CRI light only puts out about 20 to 25 lumens per watt and lasts 750 to 1,000 hours. A slightly more efficient halogen lamp with crisp 3000K, 100 CRI light produces about 30 lumens per watt and lasts about 2,000 hours. But, a screw-in compact fluorescent with an integral electronic ballast has a nice 3000K color temperature at a much better 60 lumens per watt with a rated life of 5,000 hours or better. In other words, a compact fluorescent uses a third of the energy and lasts five times longer than the typical incandescent light bulb.

The downsides of compact fluorescents are that they cost three to five times more than incandescent lamps, don't always fit in decorative fixtures, and some people find their light quality slightly lower. But from an environmental perspective, this simple lamp conversion in places where the color is less important'in downlights, closet lights, porch lights, and such'can translate into long-term energy savings and environmental benefits. And, linear fluorescent and pin-based compact fluorescent lamps'more commonly used in commercial buildings'perform even better. Despite the fact that all fluorescent lamps require a trace of mercury to operate and should be properly disposed or recycled, the energy saving benefits far outweigh the mercury issue. The less energy used, the less greenhouse gas produced by power plants.

Looking a little into the future, LED (light emitting diodes) lighting is something to watch. Although much more expensive right now than other light sources, this solid-state technology is notable for its ability to produce attractive white light at about 100 lumens per watt lasting 50,000 hours or more. Researchers predict that within the next few years, affordable consumer-grade 'white' lighting products will approach 200 lumens per watt efficacy.

Controls and Placement
Along with energy efficient sources, it is important to consider lighting controls as a great way to provide lighting flexibility as well as additional energy savings. This can range from a simple dimmer, to sensors that make sure the a light goes off when no one is in the room, to fully programmable systems tied in with a home security or entertainment system. The most efficient light is one that only gets turned on when it's needed and turned off when it's not.

Going outside, it is important to avoid light pollution and light trespass caused by unshielded outdoor lighting. Light pollution or 'sky glow' has become an important public awareness issue, as is unwanted glare or light trespass problems for neighbors. The environmental approach is to use well-shielded 'cutoff' fixtures, rather than floodlights and wall packs that emit light that points above the horizontal toward the sky. This is also energy-efficient because upward lighting (except for intentional and well-focused landscape lighting) is just wasted energy.

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