I purchased this fan to replace a fan I had on my kitchen window for over 20 years. After much research (the original fan's company went out of business) I found this fan was the closest  to my old one. It does not fit properly in my kitchen window, but I managed to hold it on by pinning it from the top to the bottom with the window. The sides are fine I had lot of lee way and did not need much. I must say it is easier to clean than my older one and it does what is promised. The three setting work great eliminating odors and recycling air. The fact that is reversible is very useful. Please keep in mind that my review is for an apartment window not a house.