One of the biggest benefits of an attic fan is its ability to efficiently lower the temperature in your home. The air in your attic can reach 150 to 160 degrees. An attic fan can lower that temperature up to 60 degrees. By lowering the temperature, the air conditioner uses less energy, which lowers your electric bill. According to the California Energy Commission, you can reduce energy use by at least 5 percent by installing an attic fan. It is best to use the attic fan in the evenings and in the morning when the temperature is lower than 80 degrees.
Another benefit of a whole house fan is the appliance's ability to lower humidity in your attic, therefore reducing any moisture build-up problems such as mold. The attic fan removes moisture from vents and helps promote a dry attic. The fresh air the attic fan brings in also helps keep cleaner, dry air in the attic. Humidity can also limit the benefits of attic fans, though, if it is too humid outside. In climates with high humidity, the attic fan is unable to bring in cooler, fresh air.
A disadvantage of a solar-powered attic fan is your location. A solar attic fan will not work efficiently if little or no sunlight can reach the fan or if there is no ventilation. Solar attic fans must have an unobstructed view of the sun. If you don't have an unobstructed view, consider an electric-powered attic fan.
While newer models of attic fans have improved on the noise created by more traditional fans, there is still some noise associated with them. This is because the fan is moving high volumes of air. Noise is something to consider if you are sensitive about noise and sleeping areas are close to the attic. Setting the fan to a lower level will help lessen the noise.
Depending on your location, using an attic fan can pose a safety hazard to you and your family. If you feel it is unsafe to have windows open on your home throughout the night, a whole house fan is probably not an option for you. The attic fan is most efficient overnight when the temperature is cooler, but you must have the windows open for it to operate.