Below are tips from in-house experts at Consumer Reports, who put the suggestions together for a brochure, "5 Ways to Cut Cooling Costs." The suggestions are reprinted with permission.
Raise temperatures a notch. Each one-degree increase on your thermostat can cut your energy bill by 3 percent or more.
Use shades, vented awnings, blinds or curtains to keep out the sun, especially in the afternoon in rooms that face west. Keep exterior doors and windows closed when running your air conditioner during the day; at night, turn off the air conditioner and open the windows to draw in cooler air when humidity is low.
Minimize heat from other sources. Turn off lamps, televisions and other heat-producing items when not in use and move them away from the air conditioner's thermostat. Use compact fluorescent lights, which create less heat than incandescent bulbs. And run dishwashers and other large appliances in the early morning or late evening when electricity use is lower and their heat has less effect on cooling.
Maintain your air conditioner. Clean or replace the filter every other week or as needed during heaviest use. Keep leaves and other debris away from the exterior condenser. (When air flow is blocked, it puts a strain on the system and lowers efficiency.) Keep condenser coils clean.
Consider fans. Use ceiling or portable fans to keep air moving. Run them only when you're in the room; otherwise, you're wasting energy.
Apartment residents in the market for a window air-conditioning unit can visit the Web site of the Association of Home Appliance Manufacturers (www.aham.org/consumer/coolload.pdf) to find a detailed, number-driven worksheet that explains how many BTUs (British thermal units) are needed for a specific space. To figure out the equation, Web site users must have a tape measure and calculator and enter information about a room's size, exposure to the elements, windows and other appliances. If you're really on top of things, you can also enter your local electric utility rates to see an estimate of the annual energy cost of operating a unit of a particular size.
For information about local utility rates, look at your electric bills or contact your power company. Local company Pepco (www.pepco.com) has a less complicated energy-usage calculator under its "Use Energy Wisely" icon so people can estimate how much money they would spend to use appliances, including air conditioners. Dominion Power (www.dom.com/customer/efficiency) also has an appliance energy-cost calculator that uses only wattage and number of hours used for its computation.
Saving energy is a good practice because it benefits both the environment and the pocketbook.
Do you have questions, comments or ideas about apartment life? Contact Sara Gebhardt via e-mail at email@example.com or by mail, c/o Real Estate Editor, The Washington Post, 1150 15th St. NW, Washington, DC 20071.