The spiral-shaped bulb is the most popular type of compact fluorescent light (CFL) bulb. Spiral CFLs create the same amount of light as traditional incandescent bulbs, but use less energy.
Many traditional bulbs around your home (from 60 w to 150 w) can be replaced with spirals. There are spirals for dimmers and three-way switches (just check the packaging), and they come in a variety of shades.
A-shaped bulbs combine the efficiency of the spiral bulbs, with the look and feel of the traditional incandescent. These products are great for consumers who don’t like the look of the spiral bulbs but still want efficient lighting. You can use A-shaped bulbs wherever you used to use traditional incandescent bulbs, such as clip-on lamp shades. Check the packaging for compatibility with dimmers and three-way fixtures.
Globe-shaped bulbs are ideal for use where you can see the bulbs, like bathroom vanity bars and ceiling pendants. A globe bulb is basically a spiral bulb with a decorative cover.
Like other covered CFLs, globe bulbs need a little time to “warm up” and reach full brightness. But be patient - ENERGY STAR® certified light bulbs generate just as much light as traditional bulbs, while using less energy.
Some of the first ENERGY STAR certified light bulbs were tube shaped. Basically straight versions of the spiral bulbs, tubed bulbs work well in lamps that have slender covers such as wall sconces.
These products are ideal for use in decorative fixtures where you can see the light bulb. The sleek shape also allows you to use them in tight fitting light fixtures where a covered globe won’t fit.
Indoor Reflector Bulbs
Reflector bulbs are perfect for providing directional light - think of recessed ceiling lights in kitchens or ceiling fans. Indoor reflector bulbs are much smaller then those that are designed for outdoor use. Some indoor reflector bulbs can be used with a dimmer - the packaging will tell you.
Outdoor Reflector Bulbs
For use outside, reflector bulbs are sealed to withstand the rain and snow. Because of this, they’re usually much larger then the reflectors designed for use inside. Timers, photocells, and motion sensors may not be compatible with CFLs so if you have one of these controls on your outdoor lights check with the manufacturer of the control and the CFL packaging for compatibility.
Fixtures or lamps with 3-way switches require the use of a 3-way CFL. Check the packaging to make sure that the bulb is intended for this use. Installing 3-way CFLs may require extra effort since they can be slightly larger than their matching incandescents, but they still use one-third as much electricity. 3-way bulbs typically come in soft white color temperature.
Fixtures or lamps with dimmer switches require the use of dimmable CFLs. Not all CFLs are dimmable so check the packaging to make sure it is. Dimmable CFLs work differently than incandescent bulbs. Incandescents dim smoothly from 100% of their light output to no output and their light color changes from a bright white to a warmer yellow. Dimmable CFLs maintain light color more consistently and dim to 10 - 40% of its original brightness. Dimmable bulbs typically come in soft white color temperature.