Fluorescent Lighting

Fluorescent lamps are considered to be the most energy efficient, but they often suffer from a reputation as flickering, eerie sources of light suitable only for institutional settings. They are the light source of choice in industrial and commercial settings because of their efficiency and long life—something worth considering for your home as well. Modern fluorescent fixtures have a place in residential settings.
A fluorescent lamp is constructed with …

• A glass tube.
• Argon or argon-krypton gas and a small amount of mercury.
• Phosphor coating on the inside of the tube.
• Electrodes at each end of the tube.

As electricity passes between the tube’s electrodes, it jostles the mercury atoms, which then give off ultraviolet radiation. The radiation is converted to light when it interacts with the phosphors lining the tube. The fixture itself comes with a ballast to kick-start the current passing within the tube and to keep it regulated. The range of phosphors available to manufacturers enables them to produce lamps with different color tones for different applications.
Fluorescent fixtures also produce less heat and more light for the amount of electricity they consume as compared to incandescent lamps.
One of the biggest changes in fluorescent technology is the shape and size of the lamps. In the past, you were stuck with straight, U-shaped, or circular figures. (The last always seemed to be used outside small-town, drive-in, ice-cream stands for some reason.) Now we have compact fluorescent lamps that can be an efficient substitute for incandescent lamps. A 40-watt compact fluorescent lamp, for example, can replace a 150-watt incandescent lamp and can last up to 10 times longer. (It had better, given the typical cost of $20 or more.) Two types of replacement units are available:

1. Integral units, which include a compact fluorescent lamp and ballast in a self-contained unit
2. Modular units, in which the bulb is replaceable Now you know that you can replace your incandescent lamps with compact fluorescent lamps, but is it worth it?

Tungsten-Halogen Lamps

These lamps (which are smaller in size than standard incandescent lamps) also heat up a tungsten filament, but they contain halogen gas. The gas combines with the evaporated tungsten to create tungsten halide gas that deposits the tungsten back onto the filament, extending its life. After the deposit, halogen gas is released and the process starts all over. The smaller size of the lamp enables the filament to heat up to a higher temperature and a higher efficiency.
Because none of the tungsten is deposited on the glass, a halogen lamp burns brighter and has a very focused, intense light.

Incandescent Lamps

This is the most familiar type of lamp. An electric current passes through and heats a tungsten filament, producing a glowing light. (The term “incandescent” literally means “to glow or become hot.”) Over time, heat evaporates the tungsten, and it eventually weakens and breaks. The lamp contains a chemically inert gas that allows the tungsten vapor from the heated element to deposit on the sides of the glass. This is why standard incandescent lamps gradually become darker over time. If they are too small, the tungsten coating would turn them opaque, and they’d be useless as a source of light. Incandescent lamps are cheap to produce and are versatile in application, but they are considered to be impractical by energy conservationists as a source of light given modern alternatives. They produce a considerable amount of waste heat for the amount of current they draw, and they have a useful life of 750 to 2,500 hours depending on the lamp. Builders traditionally install incandescent fixtures because both they and the lamps are inexpensive and are not likely to meet any resistance from price-conscious buyers. When buying lamps, take note of the voltage rating of the lamp. Typical lamps sold in stores are rated at 115 or 120 volts. At professional lighting stores, you should be able to find longer-lasting lamps rated at 130 volts.