Compact fluorescent light bulbs may be versatile, but they do have a few issues that put people off. First, they deliver their best results when left on for 15 minutes or longer. Switching CFLs on and off will shorten their life and may decrease their efficiency, mainly because the excitation of the gases and of the fluorescent coating take some exposure to an electric current to reach an optimal level. CFLs are also inefficient in enclosed, recessed fixtures (too hot) and in the fixtures of garage-door openers (too much vibration). Finally, CFL bulbs can, in rare cases, interfere with electronic equipment. This interference is caused by infrared (IR) light, which CFLs produce and which IR readers can interpret as a signal.
Benefits of CFL Bulbs
The benefits of CFLs have been grabbing headlines for the last two to three years. Indeed, if you were to focus only on the buzz surrounding CFLs, you might think that changing out your incandescent bulbs in favor of their spiral cousins would be a complete no-brainer. As we'll see later, CFLs do present some challenges and concerns. But their benefits are far more numerous.
First, CFLs use significantly less energy -- 75 percent less energy than incandescent light bulbs. That means CFLs require less wattage to produce an equivalent amount of light. For example, you could use a 20-watt CFL and enjoy the same amount of light as a 75-watt incandescent. If every home in America made one such swap, enough energy would be saved in one year to light more than 3 million homes [source: ENERGY STAR].
Of course, if you're using less energy, your energy costs are going to go down. Replacing a standard 60-watt bulb with a 13-watt CFL can save a single household $30 in energy costs over the life of the bulb [source: General Electric]. Even with the higher price tag of CFLs -- you'll pay $2 to $4 for a CFL versus 30 to 40 cents for a typical incandescent bulb -- they still save you money. That's because CFLs last a long time. In some tests, they burned brightly for 10,000 hours, whereas standard bulbs burned for just 800 to 1,500 hours [source: Johnson].
The environment comes out ahead, too. A good deal of electricity coming from coal-fired power plants gets directed to the lamps and light fixtures inside your house. If you're saving energy by using CFLs, then you're pulling less electricity from the power grid. This reduces the amount of coal that must be burned, which reduces emissions of greenhouse gases. In a single year, the use of CFLs over incandescent bulbs removes as much greenhouse gas pollution as taking 2 million cars off the road [source: ENERGY STAR].
These would be dubious benefits if CFLs didn't perform well or couldn't be used in many applications, but they are, in fact, quite versatile. Several manufacturers make compact fluorescent light bulbs that can be used with dimmer switches and in three-way lamps. And many CFL bulbs can be used outdoors as long as the fixture is enclosed. Most importantly, they give off good light. In a 2007 study conducted by Popular Mechanics, CFLs burned almost as bright and produced a better quality light than a 75-watt incandescent bulb [source: Masamitsu].
CFLs are not worry-free, however. Up next, we'll look at the biggest worry -- an element toxic to living things.