Light Bulb Fact Sheet


Light fixtures are not the only concern when it comes to lighting design. It's also important to consider which types of light bulbs to use in the different fixtures throughout your home. The look and feel of your home can be drastically improved with the right light bulbs. From incandescent to fluorescent, get the facts about light bulb types so you can light your home the way you want.

Facts about Light Bulbs:

  1. Incandescent light bulbs: Incandescent bulbs are made of glass filled with gas, and they have a filament inside which glows when it is heated by electricity. Incandescent bulbs range between 15 to 200 watts. They cost very little and can be used with dimmer switches. They're not very energy efficient, and they give off quite a bit of heat. They are sold in a variety of shapes for different lighting fixtures, and you can choose colors that are more blue to imitate sunlight or more yellow to imitate firelight.

  2. Halogen light bulbs: Halogen bulbs also use a filament that glows when it is heated with electricity; however, they are encased in quartz instead of glass, and the gas inside is different. Halogen light bulbs are more efficient and longer lasting than incandescent light bulbs because of the difference in this gas. These bulbs still give off quite a bit of heat. Generally, light fixtures that use halogen bulbs can not be converted to other types of light bulbs, often because the shape of the socket is specific to that type of bulb. Halogen bulbs can come in many types and sizes, including the G9 bi-pin bulb.

  3. Fluorescent light bulbs: Fluorescent light bulbs have trapped mercury vapor in their tubes and a coating on the inside. Electricity makes this vapor send off an ultraviolet ray and the coated tubes make the rays visible as light. Fluorescent bulbs nearly sixteen times longer than incandescent bulbs and are the most energy efficient lighting you will find. Fluorescent lighting won't work without a ballast (a device used to limit the amount of current in an electric circuit).

  4. Compact fluorescent light bulbs: Also known as CFLs, these are fluorescent bulbs that are designed to replace inefficient incandescent bulbs. They use the same technology as fluorescent light bulbs, but you do not need a ballast; they have bases that screw into standard light fixtures. They last longer and give off far less heat than incandescent bulbs. The color given off is usually close to sunlight.

  5. Bulbs for three-way switches: Three-way switches, most often found in floor lamps, allow for three levels of light. Most allow for 75-100-150 watt lighting. However, if you do not put a three-way light bulb in these lamps, the three-way switch will not work properly.

  6. The right bulb base for the socket: Every socket type requires a specific corresponding bulb base. While the threaded Edison screw base is the most common, there are several others you are likely to encounter. Other commonly used socket types are the bayonet mount, bi-post and bi-pin connectors, and wedge base sockets. Each light bulb type needed for these sockets will vary in size and brightness, and will have a unique look and material on the bottom of the bulb.

  7. Bulbs that will save you money: To maximize your budget and minimize energy use, replace your most-used light fixtures with new, energy-efficient light bulbs; you probably use your living room lamps, kitchen overhead lights, and porch lights the most. If every home changed their old light bulbs to compact fluorescent bulbs, billions in lighting costs would be saved every year and greenhouse gases from power plants would significantly decrease. For more information, read our guide on converting to energy-efficient light bulbs.

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Updated November 11, 2014