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

Label Fixtures to Deter Backsliding

When a lamp burns out, it is easy to replace it with the wrong type. The most effective way to prevent this is to label the original fixtures with the lamp types to be used. Measure 9.7.3 explains how to label fixtures to minimize these failure modes.

An Economic Example

Compact fluorescent fixtures are good devices in their own right, but they are also a fad, which causes people to use them uncritically. The economic benefit they provide may not be as great as widely assumed, so it is worthwhile to examine a typical case.

Assume that 23-watt compact fluorescent lamps are used to replace 75-watt incandescent lamps, resulting in a saving of 52 watts per lamp. Assuming a 10,000- hour life and an electricity cost of 8 cents per kilowatt-hour, each lamp replacement saves $42 in electricity cost during its life.

This is a good ratio, but variations in the assumed factors could make the economics much worse or much better. There is great variation in electricity rates. The example did not include demand charges, which are a major factor is some locations, but not in others. The example did not include labor cost for lamp replacement, which is much lower for compact fluorescent fixtures. The rate of return, as opposed to total savings, depends on the number of hours that the lamps operate each year.

If the fluorescent tube can be replaced separately, the typical replacement tube cost is about $5. Therefore, lamps with replaceable tubes may have considerably better long-term economics.

It is worth stressing that cheap junk units, which infest the market, will not last long enough to pay off. Buy for quality, not for price.

ECONOMICS

SAVINGS POTENTIAL: 50 to 75 percent of lighting energy, depending on how closely the needed lumen levels can be matched by the fluorescent lamps.

COST: Good screw-in fluorescent lamp assemblies cost from $15 to $30, depending on wattage, features, and quantity purchased. Replacement tubes alone cost about $5, for the more common types. The cost is reduced by the cost of all the incandescent lamps that would have burned out during the life of the fluorescent lamp. This is typically $5 to $10.

PAYBACK PERIOD: Less than one year, to many years. Refer to the economic example above.

TRAPS & TRICKS

SELECTING THE LAMPS: The continued popularity of junk units shows that buyers are not selecting wisely. Even the best equipment is too new to have a reliable performance record in real applications. Take care to select the proper lamp wattage and configuration for each application. Check with previous users about service life and problems.

MAINTAIN THE BENEFIT: DonÕt forget to label the fixtures.

Index

These excerpts shows the level of detail and accuracy that you'll find in the Energy Efficiency Manual by Donald Wulfinghoff. This 1500-page manual offers the most comprehensive coverage of energy-saving measures for buildings ever assembled under one cover. For more information and to view the complete table of contents, find the Energy Efficiency Manual in the Oikos Bookstore.