How much can I save by switching to compact fluorescent lamps/lightbulbs?
Although compact fluorescent lamps/lightbulbs (CFLs) are initially more expensive to buy, you should see a return on your investment and come out way ahead when you replace your most frequently used incandescent lightbulbs with CFLs. To have the same amount of lighting in a space, you can replace a 100-watt incandescent bulb with a 26-or 28-watt CFL, and it will last about 8 times longer (8,000 hours compared to 1,000 hours for an incandescent bulb) and use 70 watts less energy. On average, each bulb can save you more than $30 in electricity costs over its lifetime, and prevents more than 450 pounds of greenhouse gas emissions. In addition, a CFL produces far less heat, so may reduce cooling costs.
Currently, a CFL costs approximately $3 more than a comparable incandescent bulb. You'll end up saving the initial cost of the bulb many times over, and a CFL used for an average of four hours a day will probably not need to be changed for at least 4 or 5 years. This means less maintenance for you and less waste to landfills.
For the biggest energy savings, replace incandescents or halogens with CFLs in the rooms you spend the most time in, such as your family room, living room, and kitchen.
It is estimated that if every household in the U.S. changed just one light bulb with an ENERGY STAR® rated CFL, the nation would save enough energy annually to light more than 2.5 million homes and prevent greenhouse gases equivalent to the emissions of nearly 800,000 cars.
How do “regular” lightbulbs work?
Incandescent bulbs, or “regular” bulbs, consist of finely coiled wire filaments in a glass bulb filled with an inert gas. The wire’s resistance to the flow of electricity causes it to become hot enough to glow. About 90% of the energy used by an incandescent bulb becomes heat, and 10% becomes light. That light output is measured in lumens.
How do fluorescent lights work?
A fluorescent lightbulb is a glass tube (even the bulb-shaped ones) lined with a special phosphor coating; the tube is filled with a mixture of mercury vapor and neon or argon gas. When electricity flows through this gas mixture, it causes the mercury vapor to produce ultraviolet energy, which in turn causes the phosphor coating to emit light. Over time, molecular vibrations inside the tube cause the phosphor coating to vibrate off. When the phosphor is used up, the tube won’t light. Tri-phosphorus bulbs are a newer generation fluorescent and they give better light.
Why do fluorescent bulbs use less energy?
More of the energy of a fluorescent bulb is converted into light and less into heat. By producing less heat (about 70% less heat for an ENERGY STAR qualified CFL), fluorescent bulbs save on air conditioning costs, and you get added summer comfort as a bonus! You save twice, because you use less wattage for the same amount of light.
What is a ballast?
A ballast is the part of a fluorescent bulb that excites the phosphor molecules. Depending on the bulb, it can either be attached (integral)—as in CFLs—or be part of the fixture, as with fluorescent tubes. Ballasts can be magnetic or electronic and often last much longer than the bulbs themselves. Magnetic ballasts have a delay to start, can flicker, and make noise. Electronic ballasts can start instantly and may offer greater energy efficiency and more slender fixtures. Electronic “instant start” ballasts are often used for the 4-foot overhead fluorescent lighting fixtures frequently found in many garages, shops, kitchens, and bathrooms; however, for CFLs the instant start feature may be detrimental, because the bulb usually doesn’t last as long. If you’re interested in longer bulb life, look for CFLs that don’t mention “instant start” on the package. Also, when purchasing a new fluorescent bulb, leave it on for several hours. This process will extend the life of the new bulb.
What’s different about ENERGY STAR lighting fixtures?
Light fixtures that have earned the ENERGY STAR label combine quality and attractive design with high levels of energy efficiency, even for homes. Qualified fixtures:
How do I know how much light I’ll get if the wattage is different?
Since 1995, federal law requires both lumens and wattage be printed on bulb packages. Lumens measure light output; whereas, watts measure energy use. For example, one 100-watt incandescent bulb provides 1,710 lumens and uses 100 watts of energy. If you divide 1710 by 100, it equals 17 lumens per watt (LPW). A 28 watt compact fluorescent bulb provides similar light output, an average of 1750 lumens (1750 divided by 28 equals 63 LPW). The higher the LPW, the more light you receive for the energy used.
Is it true that fluorescent lighting is harsher than incandescent?
Not necessarily. Two factors, Color Rendering Index (CRI) and Color Correlated Temperature (CRI, sometimes seen as K), affect a light’s harshness. Fluorescent lighting is generally more uniform than other light sources.
What is the Color Rendering Index (CRI)?
CRI measures the perceived color of objects under artificial light. It is measured on a scale of 0-100. The higher the number, the more natural and vibrant an object will appear; incandescent bulbs usually have 100 CRI values. Old-style fluorescents had values of 62 at best, which is why people complained in the past that fluorescents gave false colors. A CFL with a 80 CRI or above is suitable for everyday residential use.
What is Color Correlated Temperature (CCT)?
CCT measures the appearance of the light source itself—how “warm” or “cool” it seems. It is measured in Kelvin Temperature from 0-10000+ and expressed as (K). Oddly, the lower the Kelvin number is, the warmer (more yellow) the light. For instance, a standard incandescent bulb can range from 2800-3100K. A fluorescent with a CCT of 3000K will provide the same warm, white light that an incandescent bulb produces. A 3500K fluorescent lamp gives about the same light as a halogen. As the number goes up, the bluer the light source will be. Some lamp manufacturers promote 5000-6000K as a daylight lamp.
What about halogen bulbs?
Tungsten-halogen bulbs are another form of incandescent lighting. They produce a crisp, intense white light with generally a 100 CRI. The halogen gases in the bulbs make them slightly more energy efficient than standard incandescent bulbs, but not nearly as energy efficient as fluorescents. Touching a halogen bulb when it is hot can make it burn out prematurely. Halogen bulbs burn at 700–1100 degrees Fahrenheit, hot enough to fry an egg in three minutes, while CFLs generate little heat. Halogen torchieres (floor lamps) have caused hundreds of fires resulting in serious or critical injury, and many college campuses have banned them.
What should I look for when purchasing bulbs?
Compare brands for price, lumens, wattage, hours of life, CRI, and Kelvin Temperature. CRI will be a 2-digit number and Kelvin will be a 4-digit number with K (e.g. 3500K); sometimes the CCT will be incorporated into the product number with the last two zeroes and K dropped off. Note: Check the CFL's packaging for any restrictions on use—for example, some should not be used in enclosed fixtures. Many are made for specific fixtures such as recessed cans, dimmer switches, or outdoor fixtures. Incorrectly used lamps in fixtures can be dangerous. This includes incandescent bulbs, such as using a 100 watt bulb in a fixture that calls for 40 watts.
Should I turn off the fluorescent lights when I leave the room?
Yes. Contrary to popular belief, turning off fluorescent lights saves energy. Frequent switching does shorten bulb life, but electric bill savings will more than compensate.
Can I use dimmers with fluorescent lights?
Yes—provided you pick fluorescent bulbs that are dimmable. The type of ballast used is how the lamp is made dimmable. Manufacturers are beginning to produce dimmable fluorescent lamps that will work in standard incandescent fixtures. Read package directions carefully. If incorrect bulbs are installed, it can cause fires.
Do CFLs contain mercury?
CFLs contain very small amounts of mercury sealed within the glass tubing—approximately 4-5 milligrams. Mercury is what enables the CFL to be an efficient light source. There is currently no substitute for it, but manufacturers have reduced the amount used. No mercury is released when the bulbs are in use and they pose no danger if used properly, although care should be taken when handling because the tubing is glass. Keep in mind that coal-fired power plants emit mercury. By using CFLs, and thus reducing the amount of energy used, you are reducing the amount of power-generated mercury emissions. Also, mercury in the CFLs can be recaptured through recycling.
How do I dispose of CFLs?
Don’t throw CFLs away with the household trash if there are better disposal options. Check Earth 911, which locates disposal options by zip code, call the U.S. Environmental Recycling Hotline at 1-877-327-8491, or contact your local waste-management agency for guidelines in your community. Additional information is available at Lamp Recycle If no other disposal options are available except the trash can, place used CFLs in a plastic bag and seal it. Never send a CFL or other mercury-containing product to an incinerator.