CFL vs. Incandescent

Compact Fluorescent: Making the Switch

The future looks dim for incandescent light bulbs, the world-changing invention introduced by Thomas Edison in 1879.

Part of the blame goes to CFL bulbs, also known as compact fluorescents. Consumers have turned to CFL bulbs to save money and energy. Supporters say that the new CFLs last longer and can provide users with substantial savings on their electric bills over the lifetime of the bulbs.

Phasing Out Incandescent Bulbs in the U.S.

Soon it may be hard to even buy an incandescent bulb, at least in the United States. An energy bill passed by Congress in December 2007 and signed into law by the president set energy standards that can’t be met by traditional incandescent bulbs.

The new rules will phase in beginning in 2012 and will take full effect in 2014, so consumers have a little time to get used to CFLs. And it’s likely that consumers will have more options by 2014 for replacing traditional incandescent bulbs, including advanced incandescent bulbs and cost-effective LED bulbs.

The United States is not alone in taking bold moves to save electricity. In 2007, Australia became the first nation in the world to announce a ban on traditional incandescent bulbs, which will take effect in 2010.

CFL Vs. Incandescent: What’s the Difference?

If you haven’t made the switch to CFLs, you may think that all bulbs are the same. In fact, CFL and incandescent bulbs are quite different.

How do Incandescent Bulbs Work?

Incandescent bulbs work by conducting an electric current along a filament made of a long, thin piece of tungsten metal. The filament must be heated to temperatures of about 2,300 degrees Celsius to glow and emit a white-hot light. But the process transforms only 5 percent to 10 percent of the electricity used into visible light. The rest is transformed into heat, which can eventually increase the temperature of a room.

How do CFL Bulbs Work?

CFL bulbs, on the other hand, are made of glass tubes filled with gas and a small amount of mercury. The amount is so small that an old-fashioned glass thermometer holds 100 times as much mercury as one CFL bulb. Light is emitted when mercury molecules in a CFL bulb become excited by electricity running between two electrodes at its base. The mercury emits an invisible ultraviolet light that becomes visible when it hits the white coating inside the CLF bulb.

The Benefits (and Drawbacks) of CFL Bulbs

There are definite advantages to using CFL bulbs. But for now, the bulbs aren’t popular with many consumers. In fact, although CFLs are widely available at retailers such as Home Depot and Wal-Mart, sales of the bulbs account for only 5 percent of the light bulb market.

Manufacturers of CFL bulbs promise changes in the near future that should make the bulbs more attractive to buyers. And supporters say that the benefits of CFL bulbs now on the market far outweigh their disadvantages.

Advantages of CFL Bulbs

Let’s take a closer look at why people choose CFL bulbs.

Cost Savings. Energy Star encourages consumers to think long term. According to the Energy Star Web site, an Energy Star qualified-CFL bulb will pay for itself in six months and save about $30 in electricity over its lifetime.

Energy savings. A CFL bulb uses about 75 percent less energy than a traditional light bulb. Nationwide, a 60 percent to 70 percent decrease in light energy usage would save as much energy annually as the total amount of energy used by all the homes in Texas.

Here’s another statistic: The United States could eliminate greenhouse gas emissions equal to 800,000 cars if each household in the country replaced just one incandescent bulb with a CFL bulb, according to Energy Star. Energy Star is a program of the U.S. Department of Energy and the U.S. Environmental Protection Agency designed to help consumers save money and protect the environment by using energy efficient products and practices.

Longevity. CFL bulbs last about 10 times longer than incandescent bulbs. It’s not unusual for a CFL bulb to last for five years, and even as long as nine years.

In addition, manufacturers that produce Energy Star-qualified bulbs are required to offer at least a two-year limited warranty. So if your CFL bulb burns out, you may be entitled to a refund or replacement.

Color. Earlier fluorescent bulbs were criticized for their harsh, unnatural and unflattering light tones. Manufacturers offer better options and greater variety today. In fact, a test performed by Popular Mechanics in 2007 found that the CFL bulbs scored higher for overall quality of light than the incandescent control bulbs.

Disadvantages of CFL Bulbs

Now, let’s look at some of the drawbacks of CFL bulbs.

Upfront Cost. A standard incandescent bulb costs about 50 cents. A single CFL bulb can cost $3 or more. Now imagine replacing ever bulb in your house with a CFL, and you can understand why some consumers are unwilling or unable to make the switch. But remember, buying a CFL bulb is an investment, as it will save you money over an incandescent bulb over the long run.

Delay time. Most manufacturers say that it takes a CFL bulb several seconds to reach full brightness after it is switched on. In addition, turning a CFL light bulb on and off repeatedly can shorter its life. It’s best to flip the switch only if you plan for the bulb to remain on for at least 15 minutes.
Mercury concerns. One reason that some people are leery of CFL bulbs is that each one contains about 5 milligrams of mercury, a toxic substance.

But mercury also is emitted into the air by coal-fired power plants that generate electricity. In fact, one 75-watt incandescent bulb will contribute 4.65 more milligrams of mercury into the air over its lifetime through the extra use of electricity than would be released by breaking a single CLF bulb.

Clean up and disposal concerns. A CFL bulb contains about enough mercury to cover the tip of a ballpoint pen. That may not seem like much, but it is enough for you to take the following precautions if you break a bulb.

Precautions to Take if You Break a CFL Bulb

After you’ve picked up the pieces of the bulb, wipe the area with a wet paper towel and place all clean-up materials in an outside trash can. Remember to wash your hands with soap and water when you are done. Then check with your local municipality to find out if broken CFLs can be picked up with your other garbage or if they must be taken to a specified recycling center.

The good news is that CFL bulbs are relatively difficult to break. Still, you may want to put down a drop cloth when you change one.

The mercury in a CFL bulb also means that you should not toss burned-out bulbs in the trash. Many municipalities offer recycling services, as do retailers such as Home Depot, Wal-Mart and IKEA, although not necessarily at all locations.

In the future, you may be able to return CFLs to the place you purchased them and receive a deposit back, much like cans and bottles.

Use limitations. You can’t just screw any CFL bulb into the device you want to use it in and be guaranteed that it will work. Lights with dimmer switches require the use of dimmable CFLs.

Three-way lights require three-way CFL bulbs. So check the bulb’s package to make sure you are buying one that meets your needs.

Choosing the Right CFL

CFL bulbs are relatively expensive so it’s best to read packages carefully, or be willing to make returns. Energy Star is working to persuade manufacturers to agree to standard labeling practices that could reduce confusion. In the meantime, here is some information to help you make the right choices when buying incandescent bulbs.

Wattage. Energy Star provides the following conversion chart for people looking to replace an incandescent bulb with an Energy Star-qualified CFL bulb.

• 40-watt incandescent = 450 lumens (minimum light output) = 9 to 13 watt CFL
• 60-watt incandescent = 800 lumens (minimum light output) = 13 to 15 watt CFL
• 75-watt incandescent = 1,100 lumens (minimum light output) = 18 to 25 watt CFL
• 100-watt incandescent = 1,600 lumens (minimum light output) = 23 to 30 watt CFL
• 150-watt incandescent = 2,600 lumens (minimum light output) = 30 to 52 watt CFL

Energy Star-qualified bulbs carry the blue Energy Star label.

Light Colors. Advances in technology give consumers more variety in light colors with CFLs than the sickly, antiseptic fluorescent tones that first gave fluorescents a bad reputation.

Today’s CFLs are available in a variety of mood-setting white light. To find the bulb that’s right for your needs, you’ll need to determine its Kelvin (K) temperature range. Lower Kelvin numbers mean that the light will be yellowish in tone. Bulbs with higher Kelvin numbers will produce whiter or bluer light.

Warm white and soft white lights are within the 2,700 to 3,000 K range. For a brighter white light, look for bulbs marked as 3,500 to 4,100 K. CFL bulbs in cool, white or bright white are good for kitchens or work spaces that need to be well lit. Blue light that is most like daylight will come from bulbs marked 5,000 to 6,500 K.

Shapes and Styles. Most people are familiar with fluorescent tube and spiral bulbs, but CFLs come in many more shapes. There are covered globes, candles, indoor reflectors, outdoor reflectors, and covered A-shaped bulbs that look like traditional incandescent bulbs. Dimmable and three-way CFLs also are available.

Check out the Energy Star CFL bulb comparison chart, and download the how to choose a CFL PDF file. The document includes information about different types of bulbs and the fixtures in which they work best.