A tungsten-halogen lamp is an incandescent lamp with gases from the halogen family sealed inside the bulb. Its light output is similar to that of a regular incandescent bulb, but it uses up to 40 percent less power. Although tungsten-halogen lamps are more expensive to buy, they last two to four times longer than conventional incandescents.
Tungsten-halogen lighting provides excellent colour rendering and gives off a whiter light than conventional incandescent bulbs. Tungsten-halogen lamps can be used indoors and outdoors and are suitable for gardens and marking pathways. These lamps can be dimmed, although they should occasionally be used at full power to keep the bulb from darkening.
Tungsten-halogen technology is available in several lamp types. The standard bulb is similar in size and shape to a conventional incandescent. In some wattages, these bulbs can save about 15 percent of the energy used by a conventional incandescent. Other tungsten-halogen bulbs can produce more light than a standard incandescent with the same wattage.
Tungsten-halogen lamps operate at very high temperatures and should not be used in fixtures that have paper- or cellulose-lined sockets. For greater safety, opt for a better-quality socket made from porcelain or high-temperature plastic materials. Also, choose a better-quality, medium-base tungsten-halogen lamp intended for domestic use that has a glass outer envelope to enclose the tungsten-halogen capsule inside. The envelope will contain hot glass particles if the lamp breaks. Finally, check the maximum lamp wattage and type rating of the fixture to determine if it is suitable for tungsten-halogen lamps.
Parabolic Aluminized Reflector Lamps
Parabolic aluminized reflector (PAR) lamps, typically used as spotlights or floodlights inside or outside homes, are also available with halogen technology to operate at 120 volts. A standard 150-watt incandescent spotlight can be replaced with a lower wattage halogen lamp, reducing electricity consumption by up to 40 percent. Smaller halogen PAR lamps are available for use with transformers to operate at 12 volts. These low-voltage halogen lamps are small, lightweight and provide precise control of the light beam, which makes them useful for aiming light at specific areas. (These lamps are often used in track lighting to create pools of light in a room, such as above a dining table.) Low-voltage halogen lamps are similar in efficiency to other halogen PAR lamps.
Tubular Tungsten-Halogen Bulbs
Tubular tungsten-halogen bulbs are commonly used in torchiere floor lamps. They reflect light off the ceiling, providing more diffused general lighting. However, these lamps consume significant amounts of energy (typically drawing 300 to 600 watts) and become very hot. A 300-W tubular tungsten-halogen bulb reaches a temperature of about 260°C, compared with about 60°C for a compact fluorescent bulb. This heat can be a serious fire hazard if drapes, clothing or other flammable materials come into contact with the lamp. Purchasing a torchiere with a cooler, more efficient light source, such as a compact fluorescent lamp, reduces the risk of fire and saves significant amounts of energy.
Because tubular tungsten-halogen lamps operate at a high temperature and at a high internal gas pressure, a protective shield, screening technique or both must be used to protect people and surroundings. The Canadian Standards Association (CSA) requires that these lamps be shielded to prevent fires should a lamp explode. As well, torchieres must pass a heat test to confirm that their design incorporates features such as shield or a thermal cut-out so that they will not ignite materials. Tungsten-halogens should not shine directly on surfaces, as they can burn human skin, delicate fabrics and other sensitive materials.
Halogen Infrared Reflecting (HIR) Lamps
Tungsten-halogen lamps can be made more efficient with the use of a coating that reflects infrared radiation back onto the lamp filament. A 150-W PAR lamp can be replaced with a 60-W halogen infrared reflecting (HIR) lamp, with nearly equivalent light output. Similarly, a 300-W halogen lamp used in a torchiere fixture can be replaced with a 225-W HIR lamp, improving safety and providing modest energy savings.
HIR technology is not yet available for standard incandescent bulbs, although it is under development by research organizations and industry.
A word of caution: For safety and to avoid premature lamp failure, when replacing HIR lamps installed on individual and track fixtures, it is best to turn the circuit off before unscrewing a lamp.
Torchieres or Floor Lamps
One popular type of light is the halogen floor lamp (sometimes called a "torchiere"). These lamps reflect light off the ceiling, providing more diffused and general indirect lighting. However, these lamps consume significant amounts of energy (typically drawing 300 to 600 watts) and become very hot (a 300-W tubular tungsten-halogen bulb reaches a temperature of about 260°C, compared with about 60°C for a compact fluorescent bulb).
This heat can be a serious fire hazard if drapes, clothing or other flammable materials come in contact with the lamp. In the United States these floor lamps have caused over 350 fires and 32 deaths and are banned from many university dorms.
Purchasing a torchiere with a cooler, more-efficient light source such as a compact fluorescent bulb reduces the risk of fire and saves significant amounts of energy.