A Guide to Different Types of Light Bulbs

A guide to types of light bulbs, including incandescent, compact fluorescent, HID and halogen lights.

| December/January 1992

Lighting accounts for approximately 10 percent of the total energy use in the average American home and can easily cost $100—$150 per year in electricity. While that's not a huge amount, it's more than enough to justify thinking about conservation, especially when the advantages of energy-efficient alternatives are considered. A bit of planning and investigation can put about half of that money back in your pocket, as well as saving precious energy resources.

Types of Lighting


Nearly all lighting in the home today is incandescent. In this type of light, electric current heats up a metal filament in the light bulb, making it glow white-hot and give off light. The problem is that only 10 percent of that electricity is actually used to produce light—the rest ends up as heat. During the winter months, incandescent lighting is an expensive form of electric heat; during the summer months, it makes your air conditioner work harder. Despite their inefficiency, incandescent bulbs are still a favorite among consumers because of their soft, evenly diffused light. There are more economical alternatives however, and they need not be hard on the eyes.

Tube Fluorescent Lighting  

More light is produced by tube fluorescent lighting than by any other light source. Worldwide, electricity consumption for fluorescent lighting yearly is estimated at 270 billion kilowatts—the output of more than 30 large power plants! When you think of standard tube fluorescent lighting, what probably comes to mind is the buzzing, flickering bluish-white lights in supermarkets or offices that make colors look washed-out and give some employees headaches. That is hardly the kind of light you want in your house. Well, times have changed. Tube fluorescent lighting has improved dramatically over the past ten years. Lights are available that match incandescent lights in quality, accuracy in illuminating colors, and providing a pleasant, warm atmosphere. Just as importantly, electronic ballasts that totally eliminate any hum or flicker are now available for tube fluorescent lighting. These newer tube fluorescent lights make a great deal of sense for indirect lighting around a room perimeter or above a bathroom mirror.

All fluorescent lights need ballasts to operate. The ballast alters the electric current flowing through the tube, which activates the gas inside, causing the tube to emit light. For this reason, fluorescent lamps are more complex and larger than standard incandescent light bulbs.

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