Why do some CFL light bulbs burn out sooner than others?

Some CFLs seem to burn out way before their life expectancy, and others, when of the same brand or type, may last much longer than expected. There can be many reasons for this. This list will provide some answers, and also some steps you can take to prolong the life of your CFLs.

 Be gentle. CFLs aren’t just breakable glass “bulbs”, but also sophisticated electronic devices. A drop or bang on the way home from the store might have an undetectable effect on its likely life.

  • Where possible, don’t screw a CFL in by holding the glass spiral. Use the ballast (the plastic base part) at least for the final twist. The connection between the glass spiral and the plastic ballast could be weakened in a way you won’t see, but the effect can be a shorter life for the CFL.
  • Don’t put an enclosed CFL (e.g. those with a glass outer cover such as a globe, flood, or “A” shape CFL) in an enclosed fixture (indoors, such as a ceiling fixture or wall sconce). It won’t get as hot as an incandescent bulb, but still, the confinement will cause it to run warmer than normal, and it wont last as long. It is OK to put up to a 23 watt CFL in an enclosed fixture, according to our manufacturers. CFLs above 23 watts shouldn’t be used in an enclosure, even an open ceiling can.
  • It’s perfectly OK to put an enclosed CFL inside of an outdoor fixture, such as a porch light or pole light, etc.
  • Leave it on if you’ll be back soon. Standardized testing for CFLs assumes one “on” and one “off” switch per day. Based on that and an average of 3 hours per day on, a 10,000 hour rated CFL will last over 9 years on average.
  • We’re conditioned to turn the light off when we leave the room. With CFLs, if you plan to be right back, it’s better to leave them on. The more often a CFL is turned on and off, the shorter its useful life. We’ve seen many cases where CFLs that burn around the clock – never off except during a power outage – may last two or three times as long (20,000 to 30,000 hours) as one that is turned on and off may times per day.
  • Rated lifetime is an expected average, not a fixed number. CFLs are tested in batches. If one lasts 10,000 hours, but one lasts 15,000 hours and a third lasts 5,000 hours under stand standardized testing conditions, the average is 10,000 hours. As a low cost consumer item, they will certainly vary in their characteristics. Some brands will have more variability than others. This leads to the last point:
  • Dimmable CFL bulbs. Use only dimmable CFL bulbs in dimmable fixtures. Standard CFLs will not last or work in dimmable fixtures. Bulbs have been known to start on fire because the watts are too great for the bulb.

*** It is illegal to place CFL light bulbs in the trash. Recycle them by bringing them to Home Depot, Menards or Arrowhead Electric Cooperative for free disposal.

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