10 simple ways to save energy.

Saving energy means saving pennies, but some energy-saving techniques such as adding insulation or installing new windows are costly for homeowners and unavailable to renters. Here are 10 inexpensive ways to save energy in your home or apartment without breaking the bank or launching major projects.

* Switch to compact fluorescents for your five most-used lights. Yes, compact fluorescents are initially more expensive ($2 to $20) than conventional incandescent bulbs, but some utilities subsidize them and the remaining extra cost is worth it. According to the Natural Resources Defense Council (NRDC), a single compact fluorescent will shave $60 off your energy bill in its lifetime and keep a half ton of the greenhouse gas carbon dioxide out of the atmosphere. The federal Energy Star program notes that if every household in the nation switched five bulbs, we could shut down 24 power plants. Compact fluorescent bulbs use at least two-thirds less energy and last six to 10 times longer than conventional bulbs--not a bad return on your small investment!

* Insulate your windows. If you don't have double-pane windows and can't afford to install them, consider putting up plastic. Window plastic comes in kits ($4 to $6 per window) that are available at most hardware stores, and can be installed easily. According to the U.S. Department of Energy (DOE), the pocket of air created between the plastic and the window serves as insulation, reducing heat loss by 25 to 50 percent.

* Don sweaters and fuzzy slippers. Before turning up the thermostat, ask yourself if you might be just as comfortable putting on some layers. The DOE calculates that your energy bill will go up three percent for each degree you raise the thermostat. Remember that tightly knit clothing is warmer than loose-knit, and wool is warmer than cotton.

* Use hot water efficiently. Install low-flow showerheads and faucet aerators--you'll use less water, so you'll have to hat less water. The DOE notes that a low-flow showerhead reduces the amount of water you must heat by 20 gallons, without reducing the quality of your shower. A $10 to $20 showerhead will pay for itself within three or four months. Wash clothes in cold water whenever possible and use the washer only with a full load. Keep your water heater set between 120 and 140 degrees Fahrenheit.

* Watch your appliance use. Everyday appliances siphon huge amounts of energy off the grid, but those with Energy Star ratings use 10 to 50 percent less energy than standard models. When cooking, the NRDC advises consumers to resist the urge to open the oven door to peek--each opening can reduce the oven temperature 25 degrees." Efficiency Vermont suggests keeping refrigerators at 36 to 38 degrees, and freezers at zero to five degrees. Unplug televisions when not in use, as they will continue to draw power even when switched off. Computers should be set to "hibernate" when abandoned temporarily.

* Use blinds and curtains wisely. In the winter, open window coverings during the day to let in solar radiation and shut them at night to keep the heat in. Emulate the pioneers by only exposing south and west-facing windows. In the summer, apply this principle in reverse. Keep windows shaded during the day to keep the heat out.

* Pay attention to your thermostat. The NRDC recommends setting the thermostat to 68 degrees in the winter, and dropping it down to 55 degrees when you are asleep or are away from the house for more than a couple hours.

* Stop drafts in windows and under doors. The Utah Department of Natural Resources suggests you can reduce your energy bill by 10 percent by ferreting out and sealing up air leaks. The DOE advises consumers to "pay special attention around windows and where siding or bricks and wood trim meet." Caulking, sealant, and weather stripping will do the trick and are available at most hardware stores. Cute little draft blockers can be had at most craft fairs.

* Close doors and vents to unused rooms. Many of us live in houses with more space than we need, yet we still spend the money to heat empty rooms. The DOE calculates that, "by closing the vents to just one spare bedroom in a five-room house, you can instantly cut your heating bills by as much as 20 percent."

* Use a humidifier. According to the DOE, "It's not the heat; it's the humidity." Moisture from a humidifier will increase the "heat index," making 68 degrees feel like 76. Maintain a relative humidity between 30 to 50 percent to keep condensation off the windows. CONTACT: Energy Department home guide, www.eere.energy.gov/consumerinfo/energy_savers; Energy Star, (888)STAR-YES, www.energystar.gov.

JENNIFER VOGEL is an energy-conscious Yale graduate student and E interim.