We opted not to have air conditioning since our area only has about three or four months of very hot weather, and unless it never cools off at night for an extended period of time, we can make it decently with using just fans. One of the fans that we have had remarkable help from is the twin window fan. We have several brands of them, one of which is the Pelonis twin window fan. The window fan is set up in such a way that each fan can be set to go in or out. You can have both fans sucking in air, or pulling air out of the house- this is especially helpful if you burn something on the stove and need to take the smoke out of the house. There are three speeds and a primitive thermostat which you can set which makes the fans kick on once the outside temp hits an approximate area. There are wings which can be pulled out from the sides of the fan to make them fit more accurately in the window area. Air Flow Air flow is excellent. When using the fan on the top speed, our entire room can be cooled down in just about 15 minutes. We have also had a room full of smoke emptied out in about 15 minutes by using the exhaust setting on high. Ease of Use This window fan is so easy to use- it fits perfectly in the window, although the wings on the side do not fit as tightly as they could. The plug is a bit short, but it still works. Durability We have had this fan for several years and it still works beautifully and quietly. It has been through rain storms and high outside winds, and still works nicely. Design We love this fan. I love that each fan can be independently set to work or even be turned off if you only want to use one, which we never do.