A whole house fan will help cool your entire home throughout the spring and fall allowing your central A/C to be turned off. Whole house fans work by exhausting the warm air from the day by pulling the cool evening air into your home at night. You can control the fan using a 3-speed wall switch.
Roof and gable attic fans help exhaust the hot air in your attic. Exhausting the super heated air in your attic can help your central air conditioner function more efficiently. Attic and gable fans have a built in thermostat to control the fans.