Install an automatic setback thermostat that turns off your air conditioner at night.

Opening windows costs nothing but saves a lot of energy.

Keep your windows open in the evening and overnight to allow cooler air into your home, and don't forget to turn off your air conditioner.

Close the windows during the day to keep the cool in and the heat out.

Use fans as your first line of defence against summer heat.

Ceiling fans, for instance, cost about 5¢ an hour to operate - much less than air conditioners.

To reduce air-conditioning energy use by as much as 40 percent by shading your home's windows and walls.

Plant trees and shrubs to keep the day's hottest sun off your house.

Keep blinds and curtains closed during the day to keep your home cool.

Bigger is not necessarily better.

Oversized room air conditioners use more energy and often cool and dehumidify poorly.

Measure your room and the window in which you'll mount the unit to make sure you buy only what you need.

Put the money you save on a smaller air conditioner toward a better model with a programmable thermostat or timer.

You'll use 3 to 5 percent more energy for each degree your air conditioner is set below 24°C (75°F), set the thermostat of your room air conditioner at 25°C (77°F) to provide the most comfort at the least cost.

A good air conditioner will cool and dehumidify a room in about 30 minutes, so use a timer and leave the unit off during the day.

Poorly mounted and sealed room airconditioning units allow cool air to escape outside, which means that the air conditioner must work harder and use more energy. Make sure that your unit is properly installed.

Seal any gaps around the air conditioner with foam insulation strips or removable caulking.

Keep doors to air-conditioned rooms closed as often as possible.

Clean the air-conditioner filter every month. A dirty air filter reduces airflow and may damage the unit.

Clean filters enable the unit to cool down quickly and use less energy.