How to convert incandescent wattage to compact fluorescent

Written by philip schmidt
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Compact fluorescent lamps (CFLs) save energy over conventional incandescent bulbs by producing the same amount of light at a lower wattage. While there is no exact formula for converting incandescent wattage to CFL wattage due to variations in manufacturing and product performance, you can approximate the CFL wattage by dividing the incandescent wattage by four. Other simple ways to determine wattage are described below. The key factor determining wattage equivalency is the lamp's light output, measured in lumens. Wattage is the amount of electrical power consumed by the lamp. As an example, a 60-watt incandescent lamp produces about 800 lumens of light. A CFL produces the same lumens with a power demand of only about 13 to 15 watts, offering an energy savings of about 75 to 78 per cent over incandescent lighting.

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  1. 1

    Convert the wattage of any standard incandescent lamp by dividing its wattage rating by four. This gives you the approximate wattage for a CFL with similar light output (lumens).

  2. 2

    Visit the Energy Star website (see link) to view the U.S. Environmental Protection Agency's conversion chart for the most popular lamp wattages. Many lighting manufacturers also have helpful website tools for determining the right wattage of CFL for your needs.

  3. 3

    Examine the product packaging of CFLs in the store. Many list the wattage equivalency or include language such as "replaces 60-watt incandescent bulbs." For the most accurate conversion, check the lumens rating on the CFL package, and compare that to the rating given for incandescent lamps. The lumens number tells you precisely how much light is emitted by the lamp, regardless of the lamp's wattage rating.

Tips and warnings

  • "Lamp" is the industry's term for light bulb.
  • In addition to its lumens (light output), choose a CFL based on its colour temperature. Measured in the Kelvin (K) scale, the colour temperature indicates whether a lamp's light is yellowish (or "soft," like incandescent light), bright white, or bluish-white. Soft white is in the range of 2,700K to 3,000K; cool white is 3,500K to 4,100K; natural or daylight white is 5,000K to 6,500K. Colour temperature, when available, is listed on the lamp's packaging.

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