The best way to keep a room that faces the sun cool is to keep the heat out of it. Using an air conditioner will keep a room cool, but it is costly and not environmentally friendly. Having a room that faces the sun is beneficial most of the year. In the winter, heating costs are lower because of the additional solar heat. Unfortunately, in the summer, a room facing the sun can be unbearable.
Install heat-reflecting film on the windows that face the sun. This film is inexpensive and reduces the glare from the sun as well. Do not apply the film to any windows you want to receive sun from in the winter.
Choose drapes that have a white side that faces out the window. The white will reflect the sun back. Pull the drapes during the hottest part of the day to keep the inside cooler.
Build or plant shady spots outside the part of the house that faces the sun. Encourage a shade tree or tall shrubs to grow or build a trellis or pergola and plant it with vine plants to enhance the shade.
Open windows and doors when it's cool out to encourage air flow in the house. When it's hot, shut them.
Install ceiling fans throughout the house to encourage air flow and ventilation. Use portable fans in order to keep the air moving.
Reduce the overall humidity in the home during the day. Try to do humidity producing activities like showering, cooking or using the dryer later in the day when it's not so warm inside.
Turn off lights and other heat-producing appliances to reduce the amount of heat in the room.
Paint your roof white to reflect the heat and keep the rooms underneath the roof cooler.
Insulate your attic. Upgrading your attic insulation to 12-inches can reduce the amount of cooling you need to do.