The only way you haven’t heard about compact fluorescent light (CFL) bulbs is if you live off the grid way out in the wilderness. CFL bulbs are often the first item on any “how to save on your electric bill” list, and for good reason. If CFLs are installed throughout the house, you can cut electricity use by 7 percent, which add up to significant savings on the electric bill over time. CFL bulbs also generate less heat than their incandescent cousins and can prevent greenhouse gases from entering the atmosphere–up to two thousand times their weight in greenhouse gases!

On average, CFL bulbs last 10 times longer than incandescent bulbs, and CFLs that have an Energy Star rating use 75 percent less energy than incandescents. Crunching the numbers, using a single 15-watt CFL bulb (comparable to a 60-watt incandescent bulb) can generate a monthly savings of $0.57 per month. That may sound like a small number, but multiply that by how many bulbs you use in your home, and the total may be more interesting.

But wait. These bulbs must be used properly in order to get the bang for your buck. You could completely blow the savings from CFLs if you don’t use them correctly.

Install the bulbs for their rated use. If you don’t match the bulb to the fixture, the lifespan of the CFL may be significantly shortened. The good news is that CFL bulbs now come in a wide range of designs. There are CFL bulbs specifically designed for in fixtures with dimmers, for three-way switches in lamps, and for fixtures fitted with timers. There are bulbs meant for outside use, recessed ceiling fixtures, and chandeliers. It might be that the only uses not yet covered are garage door openers and ceiling fans; manufacturers recommend not using CFLs in fixtures that are in vibrating environments.

You may need to ignore the “mom voice” in your head telling you to “turn that light off!” to get the most from compact fluorescents. CFLs need up to three minutes to warm up to full brightness and work best if they are left on for at least 15 minutes every time they are turned on, and longer is better. Though you can install CFL bulbs in fixtures and lamps that may not be on for long periods of time, you may not see the bulb life or money savings that CFLs are touted for.