Light Bulbs

Most homeowners have heard the recommendation to trade their incandescent bulbs for new types of lighting to save money on their electricity bills. However, this task can be daunting due to the large selection and different classifications of these somewhat odd-looking light bulbs. Luckily, the technology has improved rapidly over the last few years and compact fluorescent lamps (CFLs) are well-worth a few minutes’ worth of time to understand: each one uses 75% less energy and lasts 10 times longer than a standard light bulb. Other technologies like LED lights and advanced motion-sensing are gaining in popularity as energy prices rise.

Product Types

• Spiral

  
• Capsule/A-shape

  
• Reflector

  
• Globe

  
• Candle/Torpedo

  
• Tube

  
• Outdoor

  
• 3-Way

  
• Dimmable

  
• LED

  

How It Works

CFLs rely upon a completely different technology than traditional incandescent bulbs, yet still can be used in traditional fixtures. Instead of running an electric current through a metal wire, CFLs transmit electric current through a magnetic or electronic ballast to a tube with argon and a very small amount of mercury. The excited elements emit UV rays, which energizes a fluorescent coating on the inside of the tube. This coating (phosphor) releases visible light. The initial illumination requires slightly more energy than an incandescent bulb, and therefore a very slight flicker is sometimes apparent as the bulb “warms up”.

The color of the light produced by some CFLs is different than the yellowy hue of an incandescent. Light color (or shade) is measured by the Kelvin scale of temperature; lower numbers on the Kelvin scale (2700-3000K) mean that the light will appear yellow. Most CFLs are made to mimic incandescent and therefore fall in this range. Light that is brighter and cooler is ideal for kitchens and workspaces, with temperatures ranging from 3500-4100K. Light temperatures of 5000-6500K appear bluish and are excellent for reading.

Incandescent bulbs are rated sold according to their wattage, which is a measure of electricity consumption. CFLs, on the other hand, are sold by their output, in lumens. The following chart shows the approximate comparison between the two types of measurements:

Most CFLs can easily replace traditional incandescent bulbs. They combine a tube, a ballast (typically electronic), and a screw fitting to connect the lamp to the fixture. Other lamps, called “non-integrated CFLs” are comprised of separate, replaceable tubes and ballasts. Instead of a screw fitting, they use a pin base that plugs the bulb into the fixture. Most resemble the tube shaped bulb with varying numbers of tubes. These are used in dedicated fluorescent fixtures where the ballast is incorporated in the fixture, which reduces waste by allowing homeowners to only replace the tube, instead of the whole unit.

Many CFLs are named according to a two-part system that includes both the style and size of the bulb. Some examples include A19 or T8. The letter corresponds to the style and the number to the size. The most common styles are A, which corresponds to a common light bulb shape, G to globe, T to tube, and R to reflector. The size is given in eighths of an inch (8 eighths = 1 inch diameter in the case of a T8). CFLs also come in different base shapes to fit various fixtures. The most common for traditional screw fitting fixtures are candelabra, medium and mogul bases. GU10 and GU24 bases work in traditional fixtures, but use a twist and lock base. "Non-integrated CFLs" used in dedicated fluorescent fixtures rely upon a pin base used to plug the bulb into the fixture. They come in 2 or 4 pin bases.