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Ask Mr. Tight Watt: CFLs and Time to Fully Light  Smart Choices Archive

Ask Mr. Tight Watt: CFLs and Time to Fully Light

Mr. Tight Watt calls on expert Jeff Springer to answer a reader's question.

Ask Mr. Tight-Watt

Q: I like compact fluorescent light bulbs but they take a while to fully light.  Would increasing the gauge of the wire or using a 30 amp circuit breaker help?  When I only have one bulb screwed into the fixture, it turns on fast.  But when I screw in all four it takes a few minutes to warm up. –Cory, a Smart Choices reader

To get an answer for Cory’s question, Mr. Tight Watt called on Jeff Springer, manager, technical services group, GEN~SYS Energy, La Crosse, Wisconsin.

Jeff’s Answer: The slight delay in the starting of compact fluorescent lamps (CFL) is one the most common complaints about them. In a fixture or circuit where the lamps are located close to one another, there can be an interaction between the lamps that further delays the starting of each lamp. Because of the nature of this interaction, it is unlikely that it is related to wire size or circuit capacity. Installing larger wires and/or increasing circuit breaker size is not recommended.  

Another factor that can have a significant impact on the starting time of these lamps is temperature. Generally the lower the temperature, the longer it takes a CFL to reach full brightness. There are a number of manufacturers who now offer an “instant on” CFL that starts and comes to full brightness faster than typical compact fluorescent lamps. Informal testing indicates that these “instant on” lamps do start and reach full brightness faster, although not instantly. Generally these lamps will start providing light within one second or less and reach full brightness within one minute.  

In my own experience, I installed one incandescent in my garage along with three CFLs. When the lights were turned on, the incandescent was immediately bright while the CFLs were warming up. When the incandescent lamp failed a year later, I replaced it with a CFL so now all four lights in the garage are CFLs. I find that as I have gotten older, the CFLs now come on almost as fast as I am moving when I walk into the garage. This can probably be attributed to the newer CFLs coming on more quickly and not me slowing down! The slight delay is a small price to pay when compared to the 75% savings produced by the CFL as compared to an incandescent.    

Ask Mr. Tight-Watt a question or read answers to other questions Mr. Tight-Watt has answered.

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