ENERGY-EFFICIENT LIGHTING
FOR THE HOME
ENERGY-EFFICIENT LIGHTING
FOR THE HOME
The incandescent light bulb has been the proud symbol of good ideas since the time of Edison. Most of us have used these same pear-shaped "A-lamp" incandescents for as long as we can remember. Over the years they have helped us to cook, read, work, and play, and even have provided security and mood. But the standard A-lamp gets a "D" in energy efficiency when compared to new fluorescent (and some improved incandescent) energy-saving bulbs.
What are these energy-efficient light bulbs? How much energy do they save? What quality of light do they produce? How much do they cost? How long do they last? Where do you find them?
In the following article we'll answer some common questions about energy-efficient light bulbs, and present the information you need to buy the best light bulbs for your home. As you read, note that the word "lamp" generally refers to the light bulb itself. When referring to fixtures, we will use more specific terms like "table lamp."
What's Out There?
Incandescents
There are several incandescent bulbs that are more efficient and/or last longer than standard bulbs. Reduced-wattage light bulbs are 1%-5% more efficient than standard incandescents, but most of their potential for energy savings is from lower wattages (for instance, 67 watts instead of 75 watts). When substituted for the higher-wattage equivalents, the light output decreases, but not very noticeably. In effect, a 10%-15% energy savings can be achieved with these bulbs, although only a fraction of that savings is from greater efficiency. These lamps are sometimes marketed as "energy-savers" or "watt-misers."
Try to avoid the so-called long-life incandescents. They do last a little longer because the filament operates at a lower temperature than in standard incandescents, but they produce less light and are less efficient.
Tungsten halogen (sometimes called quartz or quartz halogen) incandescents are more efficient than standard bulbs and last three to four times longer. The filament is enclosed in a quartz glass capsule with halogen gas. The gas reacts with the tungsten evaporated from the filament, then redeposits it, improving efficiency and lifetime. Unfortunately, many popular tungsten halogen fixtures use 300-watt or even 500-watt lamps--these certainly won't save energy compared to a 60-150-watt standard incandescent! Instead of buying these fixtures, look for A-line halogens to replace standard incandescents, and reflector halogens to replace standard flood and spot lamps.
Some halogens have an infrared-reflective coating (sometimes called HIR) that makes them even more efficient. These lamps are currently available only in reflector (flood and spot) versions.
Compact fluorescents
Compact fluorescents use one-quarter to one-third as much electricity to give the same light output as a standard bulb, and last up to 10,000 hours, compared to 1,000 for the typical incandescent. Even most "long-life" incandescents would have to be replaced several times during the lifetime of a compact fluorescent.
Compact fluorescent bulbs and ballasts (for an explanation of ballasts see "Lighting Basics") can be purchased either separately (modular) or as an integral unit (self-ballasted). The self-ballasted units are cheaper up front and more readily available. The advantage to buying ballast and bulb separately is that the ballasts have lifetimes ranging from 50,000 to 70,000 hours, several times the lifetime of the bulb. So you can replace just the bulb (by far the cheaper of the two parts) five to seven times, saving money and needless waste. Your choices in modular compact fluorescents may be more limited, however--only recently did units become available with electronic ballasts. It may also be difficult to find replacement bulbs (or impossible if the model is discontinued during the lamp's lifetime).
There are several different sizes and shapes of compact fluorescent bulbs--generally they consist of phosphor-coated tubes, "folded" or curled to increase the surface area. Quad tube lamps have two u-bent sections (not technically separate tubes, although that's what it looks like) and tend to have higher output than single twin tube models. New triple tube models have three tube sections to give higher light output from a shorter bulb. Sometimes you can see the tubes; on other lamps they are enclosed in a glare-reducing casing (cylindrical or globe-shaped) that makes them look more like large incandescents.
The circline is not technically a "compact" fluorescent. It's more like a linear tube bent into a circle. Circlines tend to have poorer color rendition (except some of the newer ones) but are available with higher light output then most true compacts.
All of these lamp types come in models that can screw into existing sockets. But you will get the most out of a compact fluorescent, circline or tungsten-halogen bulb if it's used in a fixture specially designed for the bulb's shape, size and temperature sensitivity. Installing a new fixture is a permanent retrofit--there's no standard "Edison" socket to screw a standard incandescent bulb into. The fixtures can be expensive but replacement bulbs are much cheaper than new screw-in lamps.
CONTINUED ON NEXT PAGE --> Written by: Jeanne Byrne
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