Years ago in a townhouse I had a whole house fan.  I'd open all the windows a couple of inches in the evening, turn the fan on and feel the air move upstairs and be pulled out of the house by the fan. This fan is advertised as a reversible window fan and I purchased it for a 450 square foot upstairs room.  I put it in one window and on the opposite side of the room, about 23 feet away, I open the other window fully.  On an evening where there is no incoming breeze, with this set up as described above and the fan on high, I can stand 8 feet away from the open window and when it is on high, reverse speed, I can very obviously feel the air being pulled in through the open window outside. If I feel it at that point, I know it's circulating the room air and eventually pulling the warm air out. I recommend using it in this manner; if you just set it on reverse and don't open another nearby window sufficiently to pull in cool air, you might not think this is working.  In a sense, it works like a whole house fan.  Is it one? - no, it's not going to pull cool air in through your entire house unless it's a very small house.