Attic fans can be used to cool your living space any time it is cooler outside than inside your home. Attic fans pull air in through an open window or door while pushing hot air out of your home through attic vents.
Ventilation fans are designed to cool the attic with the intention of saving energy and the roof. Because hot air is full of moisture, all the water hanging out in your attic is causing condensation to build up. Excess heat and condensation causes major damage to roofs and roofing materials.
When you use a fan, energy is saved by reducing the use of the air conditioner in the home. You can use your air conditioning and whole house fan at the same time. However, if it is cooler outside than inside it doesn’t make sense to use your air conditioning.
Some would debate the effectiveness and safety of attic fans. Line-powered fans have been shown in studies to actually cost more to operate than the savings they produce. Solar-powered fans don’t draw nearly as much air as line-powered fans. One particular study found that by installing two solar attic fans in a 1000 square foot house saved about $50.00 per year in energy costs.
A solar fan operates completely off solar energy. It pulls the outside air in through existing soffit vents. It extracts the hot, humid air up through the fan and creates a constant exchange of air in your attic. Most attic fans operate with a thermostat that automatically turns the fan on and off based on a temperature the homeowner sets. It is usually recommended to use a setting of 100–110 Fahrenheit.
Installing an attic fan may require a roofer to cut and seal the roof or an electrician to connect a solar powered fan. If new vents are needed you may have to hire a carpenter.
Most fans will last 10–15 years. Once it reaches that age it may require motor replacement. Wiring and thermostat issues can be fixed by an electrician or other type of HVAC contractor.
Attic fans can cost between $300-$600 installed. You can contact your local HVAC contractor for more information.