Product review (5 stars): Cheap but does the job
This works exactly as expected. Installation was quick and easy. The supplied clamps are useless, I used metal hose clamps. The heat keeper is pretty cheaply made but for 9 dollars my expectations were pretty low. In some of the reviews, users have commented on the little round flap in the larger flap that directs the air flow. It is a bypass door. It is a safety feature so when the screen gets plugged up, air can still vent. Under normal operation, my bypass door is closed or mostly closed directing the majority of the air into my house. Some reviews comment on the screen also. The screen openings are on the larger side, I would say it is like a window screen. Yes it does blow a tiny bit of lint into the room. My dryer is in the basement, so it doesn't really bother me. Overall I'm pleased with the heat keeper and would recommend it.