Ceiling fans don't cool the air, but the breeze makes a room feel cooler, which can let you set the air conditioning a little higher without losing comfort. Turn fans off when you leave a room, since they cool people rather than spaces. In winter, many fans can run in reverse at low speed to push warm air down from the ceiling.

Window coverings can make a bigger difference than people expect. On hot days, close blinds or curtains on sunny windows to block heat. In cold weather, open them on the sunny side during the day to let warmth in, then close them at night to help hold it.

Thermal or insulated curtains can add an extra layer of protection for drafty windows. Outdoors, shade trees and awnings can help over the long term. These changes are low cost, easy to reverse and work alongside your heating and cooling system rather than replacing it.