Bulbs vary by their type of technology, the amount of light they produce, the amount of energy they use, and the color of the light they emit. Here’s what you need to know to understand the different choices and choose the bulb that’s right for your fixture and your needs.
Choose the correct bulb wattage
When you buy any lighting fixture, check the maximum wattage it will take. A bulb with too high a wattage can produce excess heat that can create a fire hazard or damage the fixture. Remember, wattage is the indication of how much power a bulb consumes, not the amount of light it generates. New U.S. packaging rules will make it easier to choose the light bulb that’s most efficient.
Efficiency ratings for bulbs
The U.S. Federal Trade Commission is requiring manufacturers of incandescent, compact fluorescent, and LED light bulbs to use new labeling on consumer packaging by mid-2011 to help consumers choose the most efficient bulbs for their needs.
For the first time, the label on the front of the package will emphasize the bulb’s brightness as measured in lumens, rather than a measurement of watts.
“While watt measurements are familiar to consumers and have been featured on the front of light bulb packages for decades, watts are a measurement of energy use, not brightness,” stated the FTC in its press release. “As a result, reliance on watt measurements alone make it difficult for consumers to compare traditional incandescent bulbs to more efficient bulbs, such as compact fluorescents.”
The new front-of-package labels also will include the estimated yearly energy cost for the particular type of bulb.
The back of each package will have a “Lighting Facts” label modeled after the “Nutrition Facts” label that is currently on food packages. The Lighting Facts label will provide information about:
- Energy cost
- Life expectancy
- Light appearance (for example, “warm” or “cool”)
- Mercury content
The bulb’s brightness, measured in lumens, and a disclosure for bulbs containing mercury will also be printed on each bulb.
Light sources – the different types of bulbs
Incandescent bulbs are the original type of bulb as designed by Thomas Edison. They produce light when an electric current passes through a filament and causes it to glow. Inexpensive and widely available, they are the most commonly used bulbs today, but are being replaced by more energy efficient choices.
Incandescent bulbs vary from 15 to 150 watts and produce a soft yellow-white light, emitted in all directions. Newer versions are available that produce a more neutral, white light color. Incandescent bulbs are available in a variety of shapes and sizes, with clear, frosted, or colored glass.
While they are less energy efficient than other light sources, incandescent bulbs are good for standard ambient lighting and for task lighting that demands high levels of brightness.
Beginning in 2012, the U.S. Energy and Independence Act of 2007 will require most incandescent bulbs to produce the same amount of light using less wattage.
General service incandescent bulbs are the inexpensive, readily available and what most of us think of when we hear the words “light bulb.” There are three basic shapes: General (traditional shape), Globe (round), and Decorative (flame, teardrop, etc.).
Reflectorized incandescent bulbs have a reflective coating inside the bulb that directs the light in one direction rather than all around. Reflector bulbs put approximately double the amount of light (foot-candles) on the subject as General Service of same wattage.
Parabolic Reflector Bulbs (PAR) control light more precisely and accurately. They direct approximately four times the light of General Service and are used in recessed and track lighting. Some feature a weatherproof casing that makes them suitable for outdoor spot and flood fixtures.
Halogen bulbs producing a bright, white light, that comes closer to replicating the color spectrum of the midday sun than incandescent bulbs. Halogens bulbs have a longer life and provide more light (lumens) per watt than regular incandescent bulbs. Their small size and intensity make halogens great for task lighting.
Since halogen bulbs burn hotter than other types, they require more caution. All halogen lamps sold in the U.S. today have approved safety shields to reduce fire risk.
When changing a halogen, be sure to wait until the bulb cools to the touch. Always use a clean rag to handle a halogen bulb, as oils from your hand will cause the bulb to burn hotter and can greatly reduce the life of your bulb.
Halogen bulbs are available in two types: line voltage (120 watt) and low voltage (12 volt).
Line voltage (120 volt) halogen bulb types
PAR 16, 20, 30 and 38 reflectorized bulbs provide better beam control than regular incandescent PAR bulbs. They are available in numerous spot and flood beam spreads and are used in track, recessed & outdoor spot and floodlights.
T-3 double-ended bulbs are available in a variety of base types and are used in wall sconces, torchieres and outdoor floodlights. The fixture controls the direction of the light.
T-4 single-ended bulbs come in both “mini-can” and “bayonet” base types and are used in wall sconces, bath brackets, torchieres and pendants. The direction of the light is controlled by the fixture.
Low voltage (12 volt) halogen bulb types
MR8, MR11, and MR16 (mini-reflectors) provide excellent beam control, and their miniature size allows them to be used in smaller track and recessed fixtures. They are also used in outdoor landscape accent lighting fixtures.
PAR36 bulbs provide superior beam control, especially over long distances. They are used in track, recessed and outdoor landscape accent fixtures.
T-4 bi-pin bulbs are miniature bulbs used in pendants, halogen desk lamps and linear, low-voltage track systems. They are widely used in cove lighting and under cabinet lighting.
Xenon bulbs have a white light similar to that of halogen but have a much longer life rating, some up to 20,000 hours, much like fluorescent. They operate at lower temperatures than halogen. These miniature bulbs are popular for strip, under-cabinet and cove lighting applications. Xenon incandescent bulbs include rigid-loop, festoon and wedge base bulb designs.
Fluorescents use 20-40% less electricity and can last up to 20 times longer than incandescent bulbs.
Screw-in Compact Fluorescents (CFLs) can be used in place of incandescent bulbs in standard lamp sockets, and today’s fluorescent bulbs can produce warm tones of light similar to those of incandescents.
If switching to a CFL from incandescent, be certain that the CFL bulb will fit in the fixture and that the bulb itself will not protrude from the shade, glass, or recessed fixture. If you want to use fluorescents with a dimmer, you must look for fluorescent bulbs labeled “dimmable.”
Because fluorescent bulbs contain mercury, it is important to dispose of them properly.
Fluorescents produce light when an electric arc passes between cathodes to excite mercury and other gases, producing radiant energy that is then converted to visible light by a phosphor coating that lines the inside of the bulb. The larger ceiling fixtures that use long fluorescent tubes have electronic ballasts that allows them to turn on instantly and operate without hum.
LED (Light Emitting Diodes)
An LED is a semiconductor chip embedded in a plastic capsule. Light Emitting Diodes (LEDs) produce light when voltage is applied to negatively charged semiconductors, causing electrons to combine and create a unit light. Because they are small, several LEDs are sometimes combined to produce a single light bulb.
LEDs have been popular in under-cabinet strips and some types of downlights, but with recent technological advances, they are being developed for more applications in the home.
In general, LED lighting is vastly more efficient and longer lasting than any other type of light source. To ensure that you are buying an LED bulb with high-quality color and energy efficiency that is as good or better than fluorescent bulbs, look for the ENERGY STAR symbol.
High-Intensity Discharge (HID) bulbs produce light when an arc passes between cathodes in a pressurized tube, causing metallic additives to vaporize. They have long lives and are extremely energy-efficient. However, with the exception of metal halides, they do not produce pleasing light colors. In residential settings, HIDs are most often used for outdoor security and area lighting.
There are four types of HIDs, Metal Halide, High-Pressure, Sodium Low-Pressure, and Sodium Mercury Vapor.Back to top