Incandescent light bulbs were invented in the late 19th century and the basic technology they operate upon has changed little since that time. Incandescent bulbs emit light by means of a tungsten wire that glows when heated by an electrical current. The bulbs are usually made of clear or frosted glass. The brightness and color of the bulb depends on the degree to which it is heated. The average temperature tungsten filaments are heated to is 2500��C.
Disadvantages of Incandescent Bulbs
In comparison with more modern lighting technology such as compact fluorescent bulbs, incandescent light bulbs have a number of disadvantages. First and foremost is their inefficiency. At the average temperature of 2500��C, only 12% of the light produced is in the visible range.
Moreover, over 90% of an incandescent bulb's energy is released as heat, not light. It is for this reason that incandescent light bulbs are often painfully hot to the touch long after they are turned off. In addition, they can heat the surrounding air, driving air conditioning costs up in hot weather.
Energy Efficient Incandescent Bulbs
Energy efficient incandescent bulbs are available. Although still less efficient than fluorescent or halogen bulbs, they can save 5-10 watts per bulb with little or no change in the amount of light they give off. So-called "long-life" incandescent bulbs are not recommended, however. They last longer, but produce less light while still consuming the same amount of energy as a regular incandescent bulb.
Popularity of Incandescent Bulbs
Despite these disadvantages, incandescent bulbs remain the most popular type of light bulb because they are:
- Inexpensive to purchase
- Great for general-purpose lighting requirements
- Available in the widest variety of shapes, sizes, colors, and kinds.
The warm light produced by the typical incandescent bulb is considered to be very flattering to skin tones. Unlike many fluorescent or halogen bulbs, incandescent bulbs can be used with dimmer switches.
Incandescent Bulb Safety Tips
When choosing incandescent bulbs, be sure to check the wattage of the light fixture, lamp, or appliance the bulb will be used with. Never exceed the specified wattage of the fixture or appliance. A 100-watt bulb placed in a 60-watt lamp will be a fire hazard. Also check the lumens produced by the bulb. Lumens are the standard measure of how much light is produced. Some inexpensive bulbs produce less than the standard light output for their wattage.
Generally speaking, when replacing bulbs it is a good idea to replace a burned-out bulb with one that is a like size and type. If you are unsure, take the bulb you are replacing with you and ask a salesperson for assistance.