Broan Model 512M 6-Inch Through the Wall Ventilator, 70 CFM, 3.5 Sones

I just installed this in our little half bath. We wanted a fan that could be installed without tearing out shhet rock to run ducting and had an exterior wall in the room. Installation of the fan was very easy and took maybe 1/2 hour. I spent most of my time trying to splice into the light circuit and pulling romex. The fan is not loud or quiet, really in between. Many of the parts are light and a little fragile, but I was able to get mine in with out much trouble and even used the mid-wall extension piece that came with it. I had to trim it with a pair of tin-snips as I only needed about an inch of it, but it all works fine.

Easy to install, works perfect, the only bad thing is that we is turn off if the wind blows outside the small window parts move and makes sounds

Ordered this to install in my sunroom (3 season room) to remove the hot air that rises when the sun pours in. Installation is not easy (probably because of the sidewalls in my sunroom) but a contractor friend of mine cut the 6" hole, wired it to a switch, and mounted it on a box on the sidewall. VOILA! I think it lowers the temperature by at least 5-10 degrees when it's hot in there. Runs quietly also.