General Lighting: Lamp (Bulb) Types

Traditionally, we call them bulbs to describe to the common round incandescent bulb, but manufacturers call them lamps because of the variety of shapes and types. Here is an introduction to different types.

Incandescent

This is the standard most people are used to. Incandescent bulbs work by using electricity to heat a filament in the bulb until it glows. The filament is either in a vacuum or in a mixture of argon/nitrogen gas. All incandescent bulbs can be used with dimmers. They produce steady warm, light that is good for most household applications. On the downside, they do produce a good amount of heat which limits their efficiency (LPW of 10 to 20). A standard incandescent bulb can last for 700-1000 hours. Soft white bulbs use a special coating inside the glass bulb to better diffuse the light; the light color is not changed.

Halogen

These bulbs work by passing electricity through a tungsten filament, which is enclosed in a tube containing halogen gas. The light produced is a brilliant white color which is ideal for situations requiring focus on small items such as hobbies, reading, writing, etc. A halogen bulb will last 2,000 to 4,000 hours. However, halogen bulbs can get much hotter than other bulbs. A 300 watt bulb may get to over 600 degrees Fahrenheit. Attention must be paid to placement of halogen bulb so that they are not accidentally touched and that they don't come in contact with flammable materials e.g. paper, cloth, curtains, etc.. In addition, halogen bulbs come with a glass filter that contains harmful UV rays within the bulb. Be careful to not touch the glass part of the bulb. The oils on your fingers will shorten the bulb life. Lastly, halogen bulbs are less efficient than incandescent bulbs because a larger portion of the power is converted into heat.

Fluorescent

This type of bulb works by passing a current through a tube (no filament) filled with argon gas and mercury. This produces ultraviolet radiation that bombards the phosphorous coating causing it to emit light. Bulb life is very long, 10,000 to 20,000 hours. Fluorescent bulbs are also very efficient, producing very little heat. Historically, there have been problems using fluorescent bulbs outside in cold environments and the light has been of poor quality (ie. not evenly distributed over the spectrum and fluctuating over time). However, newer bulbs have much better cold weather resistance and use special coatings to provide better quality light. Fluorescent bulbs are ideal for lighting large areas where little detail work will be done e.g. basements, storage lockers, etc.. Most florescent bulb types cannot be used with dimmers.

Note: Fluorescent bulbs need components called ballasts to provide the right amount of voltage. There are primarily two types, magnetic and electronic. Electronic ballasts solve some of the flickers and humming problems associated with magnetic ballasts and are more efficient, although, more expensive.

Compact Fluorescent (CFL)

They work like fluorescent bulbs in a much smaller package. In the last few years, they have much a much more efficient and viable alternative for the homeowner. Newer versions screw directly into the bases for standard incandescent bulbs. Similar to fluorescent bulbs, the produce little heat and are very efficient. Most cannot be used with standard light dimmers, although more expensive versions are available that do. They typically last up to 10,000 hours. Compact fluorescent bulbs are ideal for areas where a moderate amount of detail work is done, e.g. kitchen, dining room, living room, bedroom, etc.

Why aren't CFLs more popular?

Wattage Comparison: Compact Fluoresent vs. Incandescent

4 watts vs. 25 watts

9 watts vs. 40 watts

15 watts vs. 60 watts

20 watts vs. 75 watts

25 watts vs. 100 watts

42 watts vs. 150 watts



Source: ALA Manual