How Wall Exhaust Fans Work with Outside Vents
The purpose of an attic ventilation fan is to draw hot air out of the attic and replace it with cool air. This consistent pulling out and pushing in of air allows your attic to stay at a decent temperature and avoid moisture buildup. In order for attic ventilation to happen properly, you must make sure the soffit vents on the exterior of your home are in good working order so that the fan can pull in outside air. If the vents are clogged, the exhaust fan will still attempt to pull cool air into the attic, but it will pull it from your HVAC system instead of outside. This will actually increase your energy bill, so make sure to check your exterior vents annually.
With wall exhaust fans, your attic will stay cooler in hot temperatures. If you do not have proper ventilation, the overall temperature of your home will rise. This will cause your HVAC system to work harder, driving up your energy bills. With proper ventilation, you keep your home full of clean air and avoid the high costs of overusing your AC system.