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Understanding Bulb Wattage Numbers Spyrka Electric Santa RosaAfter so many years of using incandescent bulbs for the majority of our lighting needs, people have come to rely on bulb wattage when selecting light bulbs. With CFL, LED and other kinds of bulbs now available, wattage has become less of a decisive factor. You can get the brightness you need (measured in lumens) while using lower-wattage CFL and LED alternatives.

Bulb Wattage Measures the Power Consumed by an Appliance

When replacing one bulb type with another, you can use a different wattage and still get the same lumens.

Incandescent Bulbs

Traditional incandescent bulbs come in standard wattages including 40, 60, 75, or 100 watts. This includes the most familiar style of incandescent bulb as well as round vanity lights for bathrooms and other shapes. The 60-watt incandescent is most common in homes for lamps, ceiling fixtures, and other purposes.

Want to replace an incandescent bulb with CFL or LED lights? Know how bulb wattage and lumens correspond:

  • 450 lumens — 40-watt incandescent
  • 800 lumens — 60-watt incandescent
  • 1200 lumens — 75-watt incandescent
  • 1600 lumens — 100-watt incandescent

While exceeding an appliance’s maximum wattage will cause bulbs to burn out too quickly and may also cause a fire hazard, a lower bulb wattage does not cause any problems.

Compact Fluorescent Lights

CFL bulbs save energy because they use less electricity to deliver the same amount of brightness. That’s why CFL bulb wattage will be significantly lower than a corresponding incandescent bulb — the same amount of lumens can be produced with about 70% less energy.

Not all CFL bulbs are the same — 15-watt CFLs from two different manufacturers may produce different lumens. The packaging will typically indicate the lumens, so read the labels to make sure you get the right CFL bulbs for each location of your home.

A general guide to CFL bulb wattage & lumen conversion:

  • 11-watt CFL — about 450 lumens, equivalent to 40-watt incandescent
  • 15-watt CFL — about 800-950 lumens, equivalent to 60-watt incandescent
  • 18-watt CFL — about 1200 lumens, equivalent to 75-watt incandescent
  • 23-watt CFL — about 1600 lumens, equivalent to 100-watt incandescent

The best idea is to choose a CFL bulb intended to replace an incandescent of similar lumens. However, remember that CFL bulbs can take a minute to fully brighten. You may want to choose a higher bulb wattage for lights that only get used a few minutes at a time, such as closet lights. As long as the bulb wattage falls below the appliance’s maximum wattage there will be no risk of damage or fire.

LED Lights

Light Emitting Diodes generate even more lumens with less bulb wattage, so they can lower utility bills even better than CFLs. On the other hand, LEDs cost more to purchase and produce directional light (a beam, rather than scatter room light). For that reason, LEDs work best for flood lights, canned downlights, cabinet lights, and certain other purposes — but not so much for regular lamps and overhead room lights.

LED bulb wattage can be even less than CFLs:

  • 8-watt LED — 450-600 lumens
  • 10-watt LED — 900 lumens
  • 12-watt LED — 800-1100 lumens
  • 22-watt LED — 1600 lumens

LED bulb types vary a lot based on intended purpose, so hardware stores will have a wider variety of bulb wattage and lumens among various LED offerings.

When in doubt, remember that it’s always safe to use a different light bulb as long as it fits the socket and has equal or lower wattage. If you have more questions or want to retrofit your home lighting, ask your local electrician for help.