Product review (5 stars): ... house for probably 6 years now and couldn't be happier. Yes it is bulkier than your standard 4" ...
I've had this installed on my house for probably 6 years now and couldn't be happier. Yes it is bulkier than your standard 4" vent, but it "blows them away" (pun intended) with its energy efficiency. No more cold back draft in the laundry room. Installs the same as a standard vent, just 2 extra screws. Stop searching and buy this.