The following graphic depicts the temperature trends of the ambient air (outside), a house using a whole house fan, and a house just using air conditioning. I gathered the data over several different days and chose the ones that best represent a typical summer day in Southwestern Oregon. The timeline starts at nightfall and transitions to daytime. Both houses are trying to maintain a 75 degree temperature or less, so you’ll notice that when either house reaches 75 degrees, the air conditioning is turned on.
Below the houses are circles that represent the relative amount of energy used in each house to maintain the temperature at 75 degrees or less over the course of a night/day. From my estimates, using a whole house fan in combination with central air uses 500 times less energy than solely relying on central air to cool your house. I will be adding more details to this page as time goes on.