Garage Whole House Fans keep your garage cool and ventilated all year long. A Garage Whole House Fan operates on just a few pennies per hour, so don’t expect a high electric bill. Garage whole house fans allow you to cool and ventilate the largest portion of your home that A/C doesn’t reach. This process of cooling and ventilating allows your garage to stay cooler, longer because it is no longer working against your attic which can get up to 160 ºF.