Check the thermometer. Open any windows and doors in the house when the temperature outside is cooler than the temperature inside. Make sure the screens are in good shape so you don't get invaded by insects. Open skylights and high transom windows to let out the hot air close to the ceiling.
Close the drapes and blinds on windows and doors that face the south and west sides of the room. This will help keep out the heat and sunlight.
Turn on a ceiling fan to cool a room. During hot months, turn the fan on so the blades turn in a counterclockwise direction. If there's no ceiling fan, place a portable electric fan in the room to circulate and cool the air.
Apply weatherstripping to drafty windows and doors to keep the summer heat out, and the cooler air in. Use caulking to seal small holes and cracks.
Replace light bulbs that produce heat, such as incandescent bulbs, with energy-saving, cool light bulbs, such as fluorescent bulbs.