ENERGY-EFFICIENT LIGHTING
FOR THE HOME
ENERGY-EFFICIENT LIGHTING
FOR THE HOME
Linear Fluorescents
For many home lighting needs the most efficient light for the job is a linear fluorescent. Many people use them in bathrooms, kitchens and garages because a single fixture can brightly light a relatively large area. The most common of these linear fluorescents is the four foot T12 that we associate with offices. (T12 means that the diameter of the bulb is 12-eighths of an inch.) T8 lamps are more efficient--they are narrower (one inch in diameter) and most have better color rendition than the T12s. To replace a T12 lamp with a T8, you must buy a special ballast--for the highest efficiency, use an electronic ballast. You may have difficulty finding T8 lamps and ballasts in stores that cater to residential customers. Smaller (one or two feet long) T5 linear lamps can be mounted under cabinets or over sinks for efficient task lighting. All linear fluorescent fixtures need to be hard-wired by an electrician.
Flood and Spot Lamps
Reflector (flood and spot) lamps, used to illuminate outside areas around homes or highlight walls or artwork indoors, have reflective coatings to direct the light in a wide or narrow beam. The three major types are common reflector (R), parabolic aluminized reflector (PAR), and ellipsoidal reflector (ER). Many R and PAR lamps will be effectively banned by new efficiency standards that take effect November 1, 1995. The standard incandescent 75- and 150-watt PAR lamps most commonly used for outdoor area lighting are among those that will no longer be available. Good replacements for these include halogen PARs and compact fluorescent reflector lamps (make sure they are rated for outdoor use). Halogen PARs with an infrared (IR) coating are far more efficient than the standard halogen PARs.
Light Quality
Many people distrust compact fluorescent lights because they believe the quality of light will not be as good as that of an incandescent. The fears used to be justified--the cold-looking fluorescent tubes we know from office buildings, schools, and factories can appear stark and institutional--but the newer compact fluorescents and even the full-size tube models are looking better and better.
It may be surprising, but fluorescent lamps can recreate the warm "feel" of standard incandescent bulbs. Manufacturers use "rare earth, tri-chromatic phosphors" in these fluorescent tubes to produce better quality light and color rendition.
Which fluorescent lamp gives the most pleasing light? Your own taste will decide. From one fluorescent model to another you will find variation in the color of the light and the way objects look under it. Try to find a store that has the energy-efficient alternatives on display with the lamps turned on, or ask to see a particular light powered up. But even if you don't have the opportunity to see the light or to compare various models by sight, you can still get a sense of which light will look better. Two numbers are included in lamp specifications that tell us approximately what the light will look like. They are the correlated color temperature or CCT, and the Color Rendering Index or CRI (see "Lighting Basics"). Using the values for standard incandescents as a reference, you can compare these numbers to get a rough idea of the quality of light to expect. And you can choose a compact fluorescent with either "warm" or "cool" color temperature. (Linear fluorescents come in "neutral," too.)
The quality of light given off by incandescents is not necessarily the most desirable type of illumination. One lighting scientist who has replaced the incandescent bulbs in his home with energy-efficient lights prefers the whiter light that he selected and believes the colors in his home are now more vibrant. Incandescent lighting looks "dirty" and "too yellow" to him now. When people first switched from candles and kerosene lamps to electric lights, the incandescent light surely must have looked unnatural. Yet from years of use, that light is now the standard. As compact fluorescents become more prevalent, they may replace incandescent lights as the glow of choice!
Flicker and Buzz
Do fluorescent lights flicker? The question is more complex than it may seem. Fluorescent lights need a ballast to operate and there are two kinds of ballasts--magnetic and electronic.
The glow from a fluorescent lamp with a magnetic ballast actually dims momentarily every 1/120th of a second because of normal oscillations in the alternating current. Although this variation is not actually visible as a flashing of the light, it may cause eye-strain, headaches, or other problems for some people. Fluorescent lights that clearly flicker even after they are warmed up, perhaps a few times per second or slower, are simply defective.
Compact fluorescents are much less likely than their full-sized relatives to present such problems. Using lamps with electronic ballasts eliminates the possibility of a flicker. These ballasts raise the frequency of the lamp current far above the rate of change that the eye can perceive.
Occasionally a magnetic ballast will emit an unnerving hum. This ballast is a piece of iron with wires wrapped around it and the electricity passing through the ballast can cause audible vibrations (often when the ballast is old and needs to be replaced). Electronic ballasts stay quiet because of their higher frequencies.
Compact fluorescent lights with magnetic ballasts may blink a few times when you first turn them on, and many models (including those with electronic ballasts) take up to a minute to come to full brightness. This doesn't mean they're defective. In fact, the bulbs that come to full brightness more slowly are likely to last longer, and will probably suit most of your lighting needs just as well.
Which One Goes Where?
Which lamps should you replace with energy-efficient bulbs? There are several factors involved in determining whether retrofit is appropriate for a given fixture.
How Much Are the Lights On?
You will save the most energy by replacing lights that are on many hours per day. A light that is on less than a couple of hours per day will take a long time to pay back the initial investment. For instance, if you have a 60-watt A-line incandescent closet light that is on only 5 minutes per day, the simple payback time (at an electricity rate of 8.7 cents per kWh) for a $19.00, 15-watt compact fluorescent replacement is 160 years! But use that same bulb five hours per day, and the payback falls to about two and a half years.
Fixture Size
Most residential lighting fixtures in the United States are intended for standard incandescent lamps. While many compact fluorescent lamps are designed to screw into the same sockets, the bulbs tend to be bigger and heavier than the incandescents they replace. Because of this, ordinary incandescent fixtures are sometimes too cramped for some compact fluorescents. Choose the shape and size of the new lamp according to the fixture's dimensions.
If a fluorescent is too large to fit inside a lamp shade harp (the metal bracket that holds the shade above the bulb), harp extenders can be purchased at a hardware store that will solve the problem by both widening and heightening the space available for the bulb. Fortunately, the harp extenders are a one-time, small ($1-$2) investment. Some lamps arrive with plastic harp extenders in the package. One problem with harp extenders, however, is that they raise the lamp shade, which may partially expose the lamp to view.
A circular compact fluorescent may be the solution if the double or triple tube models are too tall for a lampshade. The harp fits between the ballast and the circular lamp, making the height unimportant, although you may still need harp extenders to widen the space for the ballast. Circular fluorescents are also available in higher wattages than the truly "compact" fluorescents, making it easier to replace incandescents of 100-watts or greater.
The extra weight of compact fluorescents may make some standing lamps too top-heavy or unbalance hanging fixtures. Newer compact fluorescents with electronic ballasts are smaller and lighter than magnetic models.
Location Can Affect Light Output
Even if a compact fluorescent and an incandescent bulb have the same rated lumen output (see "Comparing Light Output"), they may produce different amounts of light at the point of use, depending on the shape and color of the lamp shade or fixture lens. In general, light from fluorescents tends to be more diffuse than incandescents since light is emitted from the phosphors all along the bulb. Incandescents, with glowing filaments, are more of a "point source." Also, when compact fluorescents are installed base down, the wide ballast blocks some of the light from shining directly underneath the bulb.
Reflectors are sometimes built into recessed "can" fixtures to direct more light out of them. These reflectors may be designed for a specific shape of bulb, as one energy-conscious homeowner discovered when he changed all the bulbs in recessed ceiling fixtures to tungsten-halogen bulbs. The new bulbs were more efficient than the previous ones but were also considerably shorter. Since the reflectors in the fixtures were designed to project light from a certain point in the bulb, using a shorter bulb drastically cut the light leaving the fixtures. In this case, the improvement in efficacy of the bulb was swallowed up in the greater loss of efficacy of the bulb and fixture together.
Another phenomenon not widely known is that the light output from (and thus the efficacy of) many compact fluorescents decreases when they are installed base-down instead of base-up. This means that if you put your compact fluorescent in a ceiling fixture hanging down, it may emit more light (lumens) than if you put the same lamp "right-side up" in a table lamp. The base-down lamp will still be more efficient than an incandescent, but you may need a higher-wattage compact fluorescent than you would choose from a simple comparison of rated lumen output. Circlines and certain shapes of compact fluorescents are less likely to have this problem. Once new labeling requirements go into effect, manufacturers will have to indicate whether the position of the bulb affects its light output (see "New Labels").
Ambient Temperature and Humidity
Many fluorescent lamps are unsuitable for outdoor use in cold climates. They may not function at all at low temperatures because the ballasts won't start the lamp below a certain temperature. In this regard, electronic ballasts perform much better than magnetic ballasts. Typical magnetic ballasts won't start below 40deg.F; electronic ballasts function down to 0deg.F.
Cold can also affect the light output of the lamps. An exposed compact fluorescent at 0deg.F burns only faintly. If the bulb is housed in a sealed fixture, the lumen output will improve because the bulb will warm itself. Choosing a bulb with higher lumen output will help, both because the bulb is intended to produce more light and because it will heat the fixture to a higher temperature. Make sure an enclosed fixture has ventilation slots, however, because too much heat build-up can also affect the bulb's performance.
Look on the package to see if there are temperature and humidity restrictions on a particular light you want to buy. Generally, the newer models of compact fluorescents are less temperature-sensitive.
Dimmers
If a light is on a dimmer switch, fewer energy-saving retrofits can be used. In general, dimming rules out compact fluorescents, though a few exceptions are appearing on the market and are likely to become more common in the future.
If you have dimmable incandescent fixtures, adjusting the light level only as high as you need saves energy. But don't buy light bulbs that are brighter than you'll ever need at full power. You save more energy by replacing a 100-watt bulb with a 60-watt bulb than you do by dimming the 100-watt bulb to provide the lower light output.
Tungsten halogen incandescent bulbs will darken if they are always dimmed. Unlike most bulbs (incandescents and fluorescents), tungsten halogens maintain over 90% of their original lumen output throughout their lives. However, to do so they must operate at least part of the time at full power, so they can reach an adequate temperature for the bulb to be self-cleaning.
Even undimmed, some older models of tungsten-halogen bulbs that contain diodes may flicker noticeably. Some people can see a flicker at 60 times per second from these bulbs and may find it disturbing. Dimming the light makes the flicker more pronounced.
Accessibility
Keep in mind the accessibility of the light you are thinking of replacing. If it is difficult to reach, the importance of the lifetime of the lamp increases. Because of their long lifetime, compact fluorescents are a good retrofit for the lights that are both inaccessible and used many hours per day. Installing a compact fluorescent bulb can save you several trips up the ladder and awkward reaches. Don't be tempted by the "long-life" incandescent bulbs--they will cost more energy and money, because they are even less efficient than plain incandescents, and their lifetime is generally still quite short compared to compact fluorescents.
Disposal
All fluorescent lights contain small amounts of mercury. The newer bulbs contain less, but mercury is essential to the operation of fluorescent lights. The mercury poses no threat while it's in the bulb, but it does cause an environmental hazard for disposal. If you break a bulb, try to avoid inhaling the mercury. Use a wet rag to collect the debris immediately and put it in a container with a lid for disposal. If you think you may have missed some, air out the room where the bulb broke.
Some compact fluorescents with magnetic ballasts also contain a small amount of short-lived radioactive isotopes. (Radioactive content will be listed on the label of any lamp that contains these elements.) The radioactivity would only be released if the lamp were completely crushed. Compact fluorescents with electronic ballasts, and most with magnetic ballasts, do not contain any radioactive materials.
As with any consumer product that contains hazardous materials, you shouldn't toss your old fluorescent light bulbs in the garbage. Find out if there is a recycling program for them in your community or, if necessary, dispose of them as hazardous waste with batteries, paints, and other household hazardous wastes.
Before condemning compact fluorescents on environmental grounds, consider that operating incandescent bulbs typically creates much more pollution from power plants (including mercury and long-lived radioactivity) than using the compact fluorescents that replace them.
Availability
Where do you find energy-saving lamps? Most stores that carry ordinary A-line incandescents, unfortunately, don't carry many energy-saving alternatives. You may see some reduced-wattage incandescent bulbs, but finding compact fluorescents and tungsten-halogens is not as easy.
Even if an energy-saving light bulb appears on the shelves of the local grocery store, check the yellow pages for a store that specializes in lighting to get a wider selection of brands and bulb types. It's easy to get dicouraged about compact fluorescents if your choices are limited to one or two models that don't fit in your fixtures or have poor color rendition. You can obtain a broad range of bulbs and fixtures by mail from catalog companies (see "Mail Order Catalogs"). Your utility may also offer rebates on lamps or fixtures, or even give away compact fluorescent bulbs.
Comparing Costs
Will My Utility Bill Be Lower?
Yes, but it may not be easy to observe due to fluctuations in electricity use patterns and length of meter-reading periods. The reduction will be most noticeable in cases where many lights, operating many hours per day, are replaced. Apartment building owners, for example, experience dramatic electricity savings after replacing incandescent bulbs in hallways with fluorescents. In addition, large cash savings are obtained in avoided purchases of new bulbs. In this section, we look more closely at costs and techniques for comparing the economics of different bulbs.
Written by: Jeanne Byrne
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