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Using CFLs in Light Fixtures

Electrical and Lighting, Ask Danny, Green Living Published 01/23/2008 by Danny Lipford

My light fixtures have a maximum rating for wattage bulbs (i.e. 60 watt, etc.). If I change to the energy efficient bulbs (screw in fluorescent) do the recommended wattage ratings still apply? I thought that the wattage rating has to do with the amount of heat that the bulb generated thus creating a fire hazard. The fluorescent bulbs do not generate as much heat as the incandescent bulbs so can I go up on the bulb wattage? The same wattage fluorescent bulbs seem dimmer than the incandescent bulbs. - Thanks Ricky

Hi Ricky,

Yes, you can use a compact fluorescent (CFL) bulb that produces more light as long as it doesn’t exceed the wattage recommended for the fixture.

Light bulbs are commonly compared using both watts and lumens. Watts are the amount of electricity used by the bulb while lumens measure the light produced. Light fixtures have a maximum wattage rating to prevent the wiring and area around the fixture from overheating and causing a fire. Since CFLs uses a fourth the electricity of a comparably bright incandescent, they produce far less heat. So you can use a compact fluorescent bulb that gives more light (lumens) than an incandescent as long as it doesn’t consume more electricity (watts) than the fixture recommends.

To give an example, say your light fixture calls for a maximum of 60 watts. A CFL bulb that produces the same amount of light as a 60 watt incandescent bulb (900 lumens) only uses around 15 watts of electricity. So you can put a CFL in the fixture that equals the light output of a 100 watt incandescent (1,600 lumens) and still only use 25 watts of electricity.

When comparing the light output of the two types of bulbs, remember that it takes CFLs a few minutes to reach their peak light output. More information on compact fluorescent light bulbs can be found in our article CFL: A Bright Idea for Going Green.