Something else worth looking into that I didn't think about that West Coast Canuck mentioned was the Maxx Air II covers. Very nice to have. I have them on both of my vents. Technically, the regular Maxx Air cover is not rated for fan vents, but the Maxx Air II is rated for low power vents. Considering the price difference from the Fan Mate I went with the Maxx Air II over my bath vent and it works fine, no issues. If you don't have them yet they are a good addition.