CFLs produce light differently than incandescent bulbs. In an incandescent, electric current runs through a wire filament and heats the filament until it starts to glow. In a CFL, an electric current is driven through a tube containing argon and a small amount of mercury vapor. This generates invisible ultraviolet light that excites a fluorescent coating (called phosphor) on the inside of the tube, which then emits visible light.
CFLs need a little more energy when they are first turned on, but once the electricity starts moving, CFLs use about 70% less energy than incandescent bulbs. A CFL’s ballast helps “kick start” the CFL and then regulates the current once the electricity starts flowing.
This entire process typically takes 30 seconds to 3 minutes to complete, which is why CFLs take longer than other lights to become fully lit. CFLs with decorative covers like globe or reflector shapes have a unique design challenge that results in the tradeoff of a slower warm up time, which is why these CFLs take longer than bare spirals to reach full brightness.
Older CFLs used large and heavy magnetic ballasts that caused a buzzing noise in some bulbs. Most CFLs today – and all ENERGY STAR certified CFLs – use electronic ballasts, which do not buzz or hum.
Tips to buy:
- Look for the ENERGY STAR label – Learn more about why to choose ENERGY STAR.
- Decide how much light you need – Remember that Lumens measure brightness, not Watts
- Check the package for the bulb’s recommended use – New bulbs are specially designed for certain applications, let the package be your guide!
- Think about the mood you want from your light – Choose a light color from warm to cool for your needs.
How do I get the most from my CFLs?
- Do the twist – Screw in your CFL by holding the ballast (the white plastic part), NOT the glass tubing.Photo of a light switch being flipped
- Don’t flip too fast – You’ll maximize the lifetime savings and effectiveness of your CFLs by keeping them on for 15 minutes or more at a time.
- Choose 3 for 3 – Only use bulbs labeled as three-way on three-way sockets.
- Don’t dim a non-dimmable – Only use bulbs labeled as dimmable on dimmer switches.
- Check your controls – Most photocells, motion sensors and electric timers are not designed to work with CFLs. Always check with the manufacturer of the control for compatibility.
- Give them air – CFLs are sensitive to extreme temperatures, so place your CFLs in open fixtures indoors. Using them in enclosed fixtures indoors can create a hot environment that reduces the lifetime of your bulbs. Note that covered reflectors are best used in recessed cans.
- Protect them outside – Protect bulbs from the elements by placing them inside enclosed fixtures outdoors. For colder climates, look at the packaging for optimal operating temperatures.