Incandescent, LED, Fluorescent, Compact Fluorescent and Halogen Bulbs

Imagine your home or office without light. Light allows us to see, create a comfortable environment, be safe and secure. The lighting techniques - the ways you arrange lights - and the lamps - the light bulbs - you choose for the rooms in your home or office will make a difference in your comfort level and energy use.

Everyone knows that appliances, like your refrigerator and dishwasher, use electricity. However you may not realize lamps or bulbs and the fixtures in which they operate (called luminaries) are also appliances. If we consider lighting as a single appliance, it can be much as 25 percent of your home's electricity consumption.

When choosing many appliances, consumers can compare EnergyGuide labels, telling them how much it will cost each year to operate the appliance. This information allows people to choose an appliance at a higher initial cost if they know it's more efficient and will save them money in the long run. Not so with lamps. It is more difficult to calculate efficiency and savings because of the different lighting technologies.

To help in you choose the right lamp and fixture, ENERGY STAR® provides a list of lighting fixtures and bulbs that meet Federal energy-efficiency standards.


What Is A Watt?

It's important to understand energy use in lamps when you choose from today's full array of lighting technologies. The amount of light given off is measured in lumens. One lumen is the equivalent of the light given off by one candle. A watt, on the other hand, is the amount of electricity a light bulb uses to produce light - it's not an indication of brightness.

The distinction is important, because a new 13-watt compact fluorescent light bulb produces as much light - as many lumens - as a traditional 60-watt incandescent bulb. As much light, using only one-quarter of the electrical energy!

That's why one of the easiest and fastest ways to cut your home or office energy bill is to improve its lighting efficiency. If you replace 25 percent of the lights in high-use areas with fluorescents, you can save about 50 percent of your lighting energy bill.


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Incandescents - The Usual Light Bulbs

Thomas Edison invented the incandescent light bulb nearly 120 years ago, and it still works pretty much as it did then. Inside a glass bulb, electricity heats up a wire filament, causing it to glow and give off light. Of course, electrical heaters work in much the same way, and that's why more than 90 percent of the energy produced by incandescent lights is heat, not light. As a result, incandescents are inefficient light sources. The heat they produce can drive up your electricity bill in hot weather if your home or office is air-conditioned.

While regular incandescent bulbs last usually between 750 to 1,000 hours before burning out, some long-life bulbs last up to 2,500 hours. The trade off is that long-life bulbs are less energy efficient and produce less light per watt.

On the plus side, we're all used to incandescent bulbs - they are inexpensive to purchase, the color of the light they produce is good, and they work well with dimmers. More information is available on the Lighting Controls page.


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LEDs - Higher Efficiency, More Choices, and Prices are Coming Down

LED bulbs

Photo by: Dennis Schroeder, NREL 19468

The light-emitting diode (LED) bulb uses a semiconductor as its light source, and is currently one of the most energy-efficient and quickly developing types of bulbs for lighting your home. LEDs increasingly are being purchased to replace incandescent and other types of bulbs. LEDs are relatively more expensive than other types of bulbs, but are very cost-effective because they use only a fraction of the electricity of tradtional lighting methods and can last far longer.

Many researchers and manufacturers are currently working hard to develop new and better LEDs for consumer use, and consumer prices are falling as the market grows. LEDs for the home are available in many different varieties, ranging from recessed fixtures, track lights, and traditionally shaped bulbs that can be used to replace incandescents in lamps and fixtures.

The U.S. Department of Energy estimates that rapid adoption of LED lighting over the next 20 years in the United States could save about $265 billion in energy costs and replace the construction of 40 new power plants. For more information on LED bulbs for the home, visit the Energy Star website.


Halogen Lights

Standard halogens are more efficient, modern versions of Edison's incandescent bulb, and they last longer - 2,250 to 3,500 hours. Often they feature a parabolic aluminized reflector to improve the focus of the light. They give off a crisp, very bright, white light, and they maintain their light output over time without fading with age, as incandescents do. As a result, most automobile headlights are halogen now.

While standard halogens are efficient, most people use much more wasteful high-wattage halogen tubes in their homes. It's estimated between 30 and 40 million free-standing torchiere lamps are in use today. These floor lamps throw great amounts of light onto the ceiling, using either a 300- or a 500-watt halogen tube.

Unfortunately, these cheap and convenient halogen tubes waste energy by creating four times more heat than the average incandescent bulb. A 500-watt halogen reaches temperatures of over 1,200 degrees - creating a serious fire hazard. Curtains and other combustible materials can easily ignite if they get too close to the lamp.

The danger of fire is so great that some American universities have banned halogen pole lamps from dormitories - a 1995 fire at Arkansas's Hendrix College caused $450,000 damage. The $90 million fire in England's Windsor Castle in 1992 was caused when a halogen lamp ignited cleaning fluid.

Halogen torchieres are an example of low-price technology that proves to be costly in the long run. Discount stores often sell 300-watt torchieres for around $15 or less. Using that lamp for two hours a day will consume nearly 220 kilowatt hours of electricity in a year, at an average cost of $18. You'll spend more for electricity each year than the lamp cost in the first place.

New, energy-efficient torchieres are on the market today that use compact fluorescent bulbs. Operating at much lower temperatures, they are not only safer than the hologen lamp, but they use just a fraction of the energy.


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Fluorescent Lights

Unfortunately, fluorescent lighting carries the old negative stigma of providing flickering, sickly-green-tinted, institutional, headache-causing, noisy light. If you think these lights are "good only for the garage, " think again.

Times have changed. Fluorescents are not only one of the most efficient options around, offering the longest-life bulb, they come in a variety of colors, types and sizes. Best of all, with the new electronic ballasts, they are quiet.

Fluorescent lights are phosphor-coated glass tubes filled with an inert gas and a small amount of mercury. Because different brands can have different mixes of gases inside, fluorescents produce a wide assortment of color light that match the warm glow of incandescents.


All fluorescent lights need a controlling ballast to operate. The ballast alters the electric current flowing through the fluorescent tube, activating the gas inside and causing it to glow. Newly developed electronic ballasts eliminate that annoying flicker and buzz that used to occur with old magnetic ballasts, which were also heavier and less efficient. But there are now even more impressive improvements to the design of fluorescent lights.

To create the same amount of light as an incandescent bulb, a fluorescent tube uses only one-quarter to one-third of the energy. Plus, fluorescents last 10 to 15 times longer - 10,000 hours or more.


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Compact Fluorescent Lights

CFL bulbs

Photo by: Dennis Schroeder, NREL 19466

When these new designs were introduced in the early 1980s, they revolutionized lighting. A variation on the fluorescent tube, compact fluorescents work the same way, only the tube has been made smaller and folded over in a way to make them fit into spaces designed for incandescent bulbs. With a screw base that fits a normal light bulb socket, they operate on a quarter of the energy used by incandescents, and last ten times longer.


Smart Shopper

As we said earlier, your lighting energy bill can be cut nearly in half if you replace 25 percent of your lights in high-use areas with fluorescents. That will save you money, but you should consider the environmental benefits, too.

A single 20-watt compact fluorescent lamp used in place of a 75-watt incandescent will save about 550 kilowatt-hours over its lifetime. If your electricity is produced in a coal-fired power plant (like 20 percent of California's electricity is), that savings represents nearly 500 pounds of coal not burned, which means that 1,300 pounds of carbon dioxide and 20 pounds of sulfur dioxide will not get into the atmosphere.

A compact fluorescent lamp will initially cost more that an incandescent bulb, but because it lasts longer and costs so much less to run, it will prove to be a better bargain over time. Just keep in mind that light bulbs cost much more to run than to buy in the first place. A 75-cent, 100-watt light bulb will cost you about six dollars in electricity over its 750-hour lifespan.

A new generation of compact fluorescent bulbs now meets the stringent criteria for long-life, energy savings, start time, color, and brightness set by the federal government's EnergyStar program. Their Web Site has a list of EnergyStar-labeled compact fluorescents suitable for table lamps, recessed lighting fixtures, surface mounted fixtures, enclosed outdoor fixtures, or almost anywhere incandescent bulbs are used.

Some utilities offer rebates on compact fluorescent lamps. Be sure to look for them - you'll save even more. And use compact fluorescents for lights you use often. The more a light is used, the faster a compact fluorescent will pay for itself. Top of Page

IMPORTANT NOTE! CFLs and regular fluorescent lamps contain a small amount of mercury, a toxic element. You must dispose of the bulbs properly and handle them properly if a bulb is broken. Many retailers, such as Home Depot and WalMart, will take old bulbs back and dispose of them for you after they have "burned out." Additionally, some people are concerned about ultraviolet light emited from CFLs. For more about the health issues with fluorescent bulbs, visit the U.S. Food and Drug Administration's website at: www.fda.gov/CDRH/radhealth/products/cfl.html.


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It's Your Money

Until recently there have been some drawbacks to compact fluorescents. They come on a wide variety of sizes, shapes and wattages, so you may have to shop carefully and try several bulbs before you find exactly the right one for your purpose, one that fits your fixture.

One on the biggest consumer complaints in the past has been that compact fluorescent lights couldn't be used with dimmers. That problem is being solved now that there are dimmable compact fluorescent lights on the market and energy-efficient torchieres being sold today that feature either fully dimmable compact fluorescent bulbs or three stages of brightness.

And finally, in the past some lower-cost compact fluorescent lights have been imported and sold in the U.S. Many of these have been of questionable quality and had a lifespan much shorter than predicted. As a result, many people who tried compact fluorescents have been unhappy with their performance.

Here's a rough comparison of the long-term costs of the two types of light bulbs:

INCANDESCENT vs. COMPACT FLUORESCENT BULBS
Bulb Type 100W Incandescent 23W Compact Fluorescent
Purchase Price $0.75 $11.00*
Life of the Bulb 750 hours 10,000 hours
Number of Hours Burned per Day 4 hours 4 hours
Number of Bulbs Needed About 6 over 3 years 1 over 6.8 years
Total Cost of Bulbs $4.50 $11.00
Lumens Produced 1,690 1,500
Total Cost of Electricity
(8 cents/kilowatt-hour)
$35.04 $8.06
Your Total Cost over 3 years $39.54 $19.06
Total Savings over three years with the Compact Fluorescent: $20.50
* Note: This price per bulb was as of early 2002. The price for CFLs has dropped dramatically, and we have seen some as low as 4 bulbs for one dollar! This price is subsidized by local utility companies to be the SAME price as regular incandescent bulbs. So, the savings, at these lowered prices, with CFLs may be even more!

Source: U.S. Department of Energy, Energy Information Administration

Shop carefully to avoid lower-cost, lower-quality lamps. When you buy, ask a salesperson about their store's return policy and any consumer complaints they've received.

Finally, consider lighting controls to further reduce your lighting costs.