This is the Bomb. 15 months non stop.
Before- I had Radon at 4.00.
Using this fan now at 1.00.
You have to however close off other openings/gaps in your basement so it draws the air from your upstairs.
It does nothing for my humidity which by the way, my de-humidifier does work overtime when using this air flow method.

Love it. Installed fan in a space under my front steps with the gas meter, electric meter, and oil tank. Floor is part of the (brick) house slab. Had always been higher humidity than the rest of the living space or outside. Now it tracks outside humidity. Fan is 110 CFM so it makes a little noise. Not a problem as this space is closed off. I did run a bead of caulk around the plate before installing (probably not really needed). Make sure it's installed tightly so it does not rattle. I like the long slots for mounting; makes it easy to find a spot to attach each corner. Had to run a short conduit and put in a (GFCI) outlet as the cord is only 6' long.

Termite inspector saw a bit of water in my crawl space -- took up the plastic and got the water to drain -- but a very humid summer, so put this fan into the metal crawl space entry door and my crawl space is dry -- wonderful tool to use. It doesn't turn off until the humidity level is at the setting on the humidistat and it pretty well ran all summer -- now, with cooler weather and when it doesn't rain -- it turns its self off.

My house here in Alabama has a "stand up " basement area surrounded by crawl space. The humidity levels this summer were pretty grim which gave a musty/moldly smell to my basement and clothes closet which backs up to the basemant stairwell.. The small openings in the brick foundation did little to circulate this basement air. I tried using a dehumidifer years ago which more than doubled my monthly electric bill.

I spent hours reading over the reviews and specifics of this unit. For the price I had little to lose. I mounted this on a 3/4" sheet of plywood fitting into the window frame which originally went to the old coal bin. I used rubber grommets for the sound installation, and made sure to weather strip between the unit and the wood. I've added a picture of the finished installation.

Where this is mounted is not a high traffic or sleeping area of my home, hence the minimal fan noise is not a problem. For the record, I sleep with a 50 year old metal box fan for white noise, so the little noise from this would not impact me personally.

I'm amazed at how the musty, damp odours are now gone. I'm very pleased in every way with this fan unit. It exceeded my expectations.

Seems to work fine for our cabin crawlspace at the lake. Straight forward installation. Quiet operation. I didn't give it 5 stars because I have not noticed that it has turned off since installing. I have the humidistat set at 67. It will turn off if I go above 70. I have noticed a decrease in the musty smell.