Q I’ve looked at compact fluorescent bulbs at the home center, but I’m not sure what to buy. How do I know which provides as much light as a regular 60- or 100-watt bulb?
A First, look at the lumen rating, not the bulb wattage, to compare “real” light output. Then buy a compact fluorescent lamp (CFL) with 20 percent more lumens than the incandescent bulb you want to replace. For example, if a 60-watt incandescent bulb has 870 lumens, buy a CFL with at least 1,050 lumens. If you follow wattage guidelines on the package (such as a 13- to 17-watt CFL equals a 60-watt; a 25- to 27-watt CFL equals a 100-watt), you may not be satisfied with the light output. This is especially true if you’re over 50, because older eyes take in only half as much light as 20-year-old eyes.
Another reason you need more lumens is that the CFL will dim over time. It will lose 20 to 25 percent lumen power after 4,000 hours (40 percent of a CFL’s 10,000-hour-rated life). Incandescent bulbs do not lose lumens, but their life is extremely short compared with that of CFLs.
Finally, while CFLs can last up to 10 times longer than incandescent bulbs, certain circumstances can shorten their life:
Compare the lumen ratings listed on the package and buy a CFL with more lumens than the incandescent bulb you want to replace.
Incandescent 870 lumens
60 watts
CFL 800 lumens
13 watts
CFL 800 lumens
14 watts
CFL 930 lumens
15 watts
