Lasko 16" Electric Reversible Window Fan W16900 - Dual Blade Cooling & Ventilation for Home, Office, or Bedroom - Energy Efficient Quiet Operation

I've had two of these fans for 4 years now. One upstairs, one downstairs, both set to exhaust. I'd have more of these if I had another window in the house small enough to accept the fan.Just in case you haven't thought about this subject before, it's a lot easier to suck hot air out of a room with an exhaust fan than it is to push cool air in to the room. Using an exhaust fan works much better than just opening a window wide and hoping cool air will blow in eventually.For summer evenings, as soon as it's cooler outside than inside, exhaust fans are the bomb.Place this fan properly in a window, so that the fan and its casing cover the entire open window area. Then open another nearby window just a few inches, and feel the cool breeeze blowing in. When I have both fans going and the patio sliding door open 6 inches you can feel the breeze 6 feet inside. It takes only about 2 hours from jump to cool my 2500 sq ft house to outside levels with both fans going. I've had to put them on timers to stop at 2am or it gets too cold.So why is this a great exhaust fan?It's not the Rolls Royce of fans. It's a good fan at a great price. You can pay 3x what this one usually costs ($50 to $80) for only marginal improvements in performance. True, it's not built like a Sherman tank but it's built plenty well enough to do its job. (I like that--you know what they say, An engineer is someone who knows how to build a bridge that barely stands, but it does stand.)Some notes:If your window opens side to side, the height of the window on the inside ledge should be at least 26.5 inches and less than 34 inches. You need to be able to open the window at least 18 inches wide, preferably 20. They say this is a 16 inch fan, but that's the blade width. The basket is a little over 18 inches. You can screw the fan into the window, if your wife will let you. For some reason wives seem to object more to screw heads sticking out in the horizontal plane of a window than the vertical. It will work just fine to wedge the fan by turning it 90 degrees and extending the side panels appropriately. The side panels can be precisely set--they have two screws on each side. You may want to put some foam rubber or other soft material along the edge of the panels to reduce vibration--I didn't find it necessary.If your window opens top to bottom, then the width of the inside window ledge should be at least 26.5 inches and less than 34 inches, and you should be able to open the window in such a way that the height of the opening is no more than 21 inches, 22 at the most. You can wedge the fan in this kind of window too, if screws still don't pass the wife test.If you use screws, use the template included with the fan, and try hard to be precise, leaving about 1/16 of an inch of space at the bottom when the fan is set in. The fan has a clever keyhole scheme for hanging it in the window, similar to the keyhole opening you use when hanging a picture on a single nail. Take the keyhole length into account when using the template or be ready to put paper towels or felt/foam rubber under the fan to stop rattle.At highest speed the fan isn't annoying--you can sleep with it in the same room if you're not a person who's bugged by white noise. At low speed, it's very quiet.It moves a lot of air. My biggest challenge is getting my wife to buy into the idea that opening one window 6 inches will cool the room faster than opening it all the way. The idea is to get a breeze sucked into the house, instead of having cool air just mill around at window boundaries.My fans have been going now for 4 years with no signs of quitting. But I did just buy another one as a backup. No reflection on the fan, I'm just one of Those Guys.Be careful with the wings that extend to fit the window. They're not unduly flimsy, but they are a little flimsy. I broke one already. Another commenter worried about getting out of a window in case of a fire if the fans were screwed in. My take is that an adrenaline-charged 6 year old would have no problem flinging this fan across the room when screwed in. If you're worried, wedge.Despite what I've said about noise and vibration, the fan is nicely balanced and not prone to excess vibration. You have to do some work mounting it correctly, but it's simple work for anyone if you relax and do it right. Get a level and a glass of wine, and you'll be fine.You will have to clean your window screens. Kind of like replacing your furnace filters. Depending on how dusty your area is, you may have to do it more than once a year.It is nice to be able to shut the window without moving the fan. Ours stay in the windows year round.Bottom line: if it gets cool enough at night in the summer where you live that you wish you could sleep outside because the house stays hot, this fan is for you, if you have windows that can fit it.