Measure 9.1.2.1 Substitute Screw-in Fluorescent Lamps for Incandescent Lamps.

Limitations

Energy Savings Potential

How to Select CFLs

Label Fixtures to Deter Backsliding

An Economic Example

Economics

Traps and Tricks

Screw-in fluorescent “lamps” are actually complete fixtures packaged on a standard lamp base. They include a fluorescent tube, a starter, and a ballast. The fluorescent tube itself may be permanently attached to the ballast or it may be separately replaceable. A large variety of configurations are available, including units with integral reflectors and various types of globes or diffusers. See Figure 1.

The best screw-in fluorescent lamps are somewhat less efficient than the best conventional fluorescent fixtures, but they are still three to four times more efficient than ordinary incandescent bulbs of similar light output. In applications such as the example shown in Figure 2, they can significantly reduce electricity cost. They last about 10 times longer, but they cost about 20 times more.

No special steps are needed to replace incandescent lamps with screw-in fluorescent units in most situations. In some cases, a minor modification of the fixture is needed. However, there are many situations where screw-in fluorescent replacements cannot be used.

Some screw-in fluorescent lamps have magnetic ballasts and some have electronic ballasts. In units made by reputable manufacturers, electronic ballasts are more efficient. They add some problems, and they eliminate others. See Reference Note 55, Fluorescent Lighting, for details about fluorescent lamps and ballasts.

Fig. 1 Three basic types. You can select a bare lamp, or a lamp with a reflector, or a lamp with a diffuser.

The newest types of screw-in fluorescent fixtures use tubes of small diameter and high brightness. These were originally called “PL” fixtures (after Philips Lighting, who introduced them), and they are now called “compact fluorescent” fixtures. Older types of screw-in fluorescent fixtures, still being offered, use a conventional circular tube of large diameter that is mounted on a screw-in ballast.

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