Product review (5 stars): Keeps heat in and cold air out
Works really well. Simple and effective design.  Keeps heat in and cold air out.

Comes with screws for installation on wood, but for me I had concrete. My install was straight ahead on my concrete basement wall as well, once I rented a hammer drill from Home Depot, and  bought some concrete screws.  It is also a good idea to seal the circle with some good quality caulking, to keep the wet dryer air going out the top, instead of leaving moisture elsewhere. Could use a paint job as well, but the current color makes it difficult to miss, and helps prevent accidental damage to the unit, (it is only heavy plastic).  I am intrigued to see how it works with Northern Alberta  -30C winters.