Most importantly, they give off good light. In a study conducted by Popular Mechanics, CFLs burned almost as bright and produced a better quality light than a watt incandescent bulb [source: Masamitsu]. CFLs are not worry-free, however. Up next, we'll look at the biggest worry -- an element toxic to living things.
Compact fluorescent light bulbs may be versatile, but they do have a few issues that put people off. First, they deliver their best results when left on for 15 minutes or longer. Switching CFLs on and off will shorten their life and may decrease their efficiency, mainly because the excitation of the gases and of the fluorescent coating take some exposure to an electric current to reach an optimal level.
CFLs are also inefficient in enclosed, recessed fixtures too hot and in the fixtures of garage-door openers too much vibration. Finally, CFL bulbs can, in rare cases, interfere with electronic equipment.
If there is an ugly truth about CFL bulbs, it's the mercury they hold within their glass covers. Mercury is a persistent and highly toxic chemical. Most humans are exposed to the poison by eating fish contaminated with methyl mercury. However, it's also possible to inhale elemental mercury vapor, like the kind used in compact fluorescent light bulbs. To see which is a bigger deal -- fish or fluorescent -- check out this related HowStuffWorks article.
So why is it there, and why don't CFL manufacturers use something else? As we mentioned earlier, mercury vapor is required to convert electrical energy to radiant energy. When stimulated by electric current, mercury vapor inside a CFL produces ultraviolet light, which is re-radiated as visible light when it strikes the fluorescent compound, known as phosphor , painted on the inside of the bulb.
No other element has proved as efficient in this process, so even though the amounts of mercury used in bulbs has decreased over time, a small amount of mercury is still required for CFLs to function properly. It's important to keep this in perspective. One CFL bulb typically requires approximately 0. Older home thermometers contain times that amount 0. So, a single CFL bulb has very little mercury.
And none of the chemical is released as long as the bulb remains intact. A broken CFL bulb, however, can expose a person to mercury vapor. A tiny amount of solid mercury powder can also be released.
For these reasons, extra caution should be taken when cleaning up a broken CFL. The U. This should take care of a broken bulb. Up next, we'll look at what to do with a CFL bulb that burns out. The good news is that CFLs, although they contain mercury, actually help eliminate mercury from the environment. Replacing a single incandescent bulb with a CFL will keep a half-ton of CO2 out of the atmosphere over the life of the bulb.
If everyone in the U. Saving electricity reduces CO2 emissions, sulfur oxide and high-level nuclear waste. They use rare earth phosphors for excellent color and warmth.
CFLs can be applied nearly anywhere that incandescent lights are used. Energy-efficient CFLs can be used in recessed fixtures, table lamps, track lighting, ceiling fixtures and porch lights. Three-way CFLs are also now available for lamps with 3-way settings. Dimmable CFLs are also available for lights using a dimmer switch.
CFLs come in many shapes and sizes. When purchasing CFLs, consult the seller for recommendations and consider the following:. CFLs with K numbers between give off a soft bright light like incandescents. CFLs with K numbers between give off a bright light. As you go up the K number scale the light gets bluish and closer to daylight.
For example: Approx. CFLs are available in a variety of shapes to fit a range of lamps and lighting fixtures. See below on this page for the most popular CFL shapes.
Lumens indicate the amount of light being generated. Wattage is a measure of energy use, not light strength. Lumen output is printed on the bulb package or on the bulb product page if purchasing bulbs online. CFLs are available in a variety of styles or shapes.
Some have two, four, or six tubes. Older models, and specialty models, have separate tubes and ballasts. Some CFLs have the tubes and ballast permanently connected. This allows you to change the tubes without changing the ballast. Others have circular or spiral-shaped tubes. In general, the size or total surface area of the tube determines how much light the bulb produces. The following CFL bulb models come with standard sockets for easy installation in most common household applications.
These bulbs are designed as a continuous tube in a spiral shape which has similar outside shape and light casting qualities to a standard incandescent bulb. Spiral CFL bulbs are made in several sizes to fit most common fixtures. These CFLs have more tubing in a smaller area, which generates even more light in a shorter bulb. They pack high light output into a very small space and can be used in fixtures designed for incandescent bulbs, such as table lamps, reading lamps, open hanging lamps, and bare bulb applications.
These are regular CFL spiral lamps which are placed inside a dome cover and fitted with a standard base which fits common lamp sockets. They are designed to give the appearance of the traditional light bulb for consumers looking for the more familiar light bulb appearance.
This shape is commonly used in bathroom vanity mirrors or open hanging lamps, and bare bulb applications. Bathroom vanities usually require multiple bulbs, which generate radiant heat. The CFL globe will reduce this heat buildup while saving energy. The glass diffuser provides a soft-white light. These lamps are designed to be ideal for recessed and track lighting fixtures, indoors and outdoors. They provide diffused, soft, white light, and generate less heat than will an incandescent flood or a halogen bulb.
CFL flood lamps are available in varying sizes and wattages. The screw-in torpedo-shape and the small-base of this bulb is designed for smaller light fixtures throughout the house, from chandeliers to sconces. To use a smaller candelabra-based bulb in a regular socket, you can use a socket reducer.
Although CFLs are an excellent source of energy-efficient lighting, they are not always the best choice for all lighting applications. Here are a few limitations to consider:. The principal reason for reduced lifespan of CFLs is heat. CFLs exhibit shorter lifespans in light fixtures and sockets where there is low airflow and high heat build-up such as recessed lighting. These bulbs should be used where they will be left on for steady periods without being flicked on and off.
Mercury is a toxic metal associated with contamination of water, fish, and food supplies, and can lead to adverse health effects. A power plant will emit 10mg of mercury to produce the electricity to run an incandescent bulb compared to only 2. The net benefit of using the more energy efficient lamp is positive, and this is especially true if the mercury in the fluorescent lamp is kept out of the waste stream when the lamp expires. The mercury in compact fluorescent bulbs poses no threat while in the bulb, but if you break one:.
We have discontinued sales of CFL bulbs because we are concerned about the inconsistent quality standards among overseas manufacturers of CFL bulbs, and the use of mercury in these bulbs. The price of LED bulbs now delivers the best cost-savings over the life of the bulb when compared to CFLs or any other light bulb available today.
When to turn off your lights — The operating life of a bulb is affected by how many times the light is switched on and off. Here are some guidelines to help you get the peak benefit from your light bulbs. Lights Out for Incandescent Bulbs Why were incandescent bulbs phased out? CFLs produce light differently than incandescent bulbs. In an incandescent, electric current runs through a wire filament and heats the filament until it starts to glow.
In a CFL, an electric current is driven through a tube containing argon and a small amount of mercury vapor. This generates invisible ultraviolet light that excites a fluorescent coating called phosphor on the inside of the tube, which then emits visible light.
This entire process typically takes 30 seconds to 3 minutes to complete, which is why CFLs take longer than other lights to become fully lit. CFLs with decorative covers like globe or reflector shapes have a unique design challenge that results in the tradeoff of a slower warm up time, which is why these CFLs take longer than bare spirals to reach full brightness.
They also make great indoor and outdoor holiday lights. With their high efficiency and lack of toxic mercury, LEDs are your best bet for reducing your energy bill and protecting the planet.
Water is life. Some of us drink it straight from our faucet without a second thought. Others go to great lengths to buy enough jugs or bottles from the store to always have on hand. Green America's website is sponsored by Green America members and.
Help us meet our Matching Gift Challenge! Why Abandon Your Incandescents? CFLs: The Better Bulbs CFLs and fluorescent tube lights are lit by an electric current that is sent through a tube containing argon and a small of amount of mercury gases. Learn about our sponsor.
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