Looking for an easy, cheap way to make your dorm room a little greener? Energy-saving light bulbs—known as compact fluorescent lamps (CFLs), compact fluorescent light bulbs, or compact fluorescent tubes (CFTs)—are a great choice. Though slightly more expensive than regular bulbs, CFLs still cost only $3 or $4. And if you pay for the electricity in your dorm room, it might interest you to know that you can save $30 or more in electricity costs over each bulb's lifetime. You might even end up with a little extra spending money.

Finding a CFL is easy. They're now carried most places that incandescent bulbs are available, and the Energy Star program (run by U.S. Environmental Protection Agency) gives a seal of approval to all CFLs that it considers 'up to snuff'. Energy Star qualified bulbs use 75% less energy and last up to 10 times longer, relative to standard incandescent bulbs

According to the Energy Star CFL website, "[i]f every American home replaced just one light bulb with an Energy Star qualified bulb, we would save enough energy to light more than 3 million homes for a year, more than $600 million in annual energy costs, and prevent greenhouse gases equivalent to the emissions of more than 800,000 cars." Not bad, no? CFLs also produce roughly 75% less heat, making them safer and cooler to use (so you can even save on cooling costs).

Finally, which bulbs to replace? And with what? Energy Star recommends replacing bulbs that get used for at least 15 minutes at a time, or that you keep on for a total of several hours each day. They also recommend that you replace bulbs in fixtures with reasonable airflow (e.g. table/floor lamps or wall sconces). If you have a recessed fixture, try a reflector CFL—it will more evenly distribute light than a spiral CFL.

A few other tips, for the professional CFL purchaser:

• If you have a dimmer or three-way socket fixture, you'll have to purchase a bulb specifically designed for these fixtures.
• The shade of light you choose can affect the mood of a room. Think about whether a cooler or warmed shade would work better.
• Look for a CFL with the right amount of light; many are labeled as equivalent to an incandescent bulb wattage.

You should also check the lumen rating to find the right CFL. The higher the lumen rating, the greater the light output. Use the table below as a guide for the CFL wattage that will best to replace your incandescent light bulb:

And it probably goes without saying, the more the merrier! If you like it, maybe you can get a friend to buy one too.