Many of the new lamps in the market can be used in your old lighting fixtures. Compact fluorescent lamps, or CFL’s, are available in a full range of light levels, and are more efficient as they offer comparable light levels to the traditional incandescent light bulb, at half to one-third of the power consumption. Typically, a fluorescent lamp will measure 90 lumens per watt, versus a standard-voltage halogen, that measures around 35 lpw.
Watts as the standard unit for describing the “strenght” of bulbs is gradually being phased out and being replaced by lumens. The American Lighting Association suggests looking for bulbs with lumens equal to traditional incandescent wattages:
Lamp efficacy is measured as the ratio of the lumens emitted by a light source to the electrical power supplied, lumens/W. For example, a 20-watt CFL can replace your traditional household 40 watts (75 A-lamp) with an average rated lamp life 750 -2,000 hours; much shorter as compared to the 10,000 hrs provided by a 11 W compact fluorescent that may offer 900 lumens.
A frequently asked question on CFL lightbulbs is about their mercury content. CFL’s contain a very small amount of mercury sealed within the glass tubing, an average of 5 milligrams. Mercury is an essential component that allows the bulb to be an efficient light source. No mercury is released when the bulbs are intact or in use. When they burn out, compact fluorescent lightbulbs should be disposed at any available local recycling depot.