Product review (5 stars): Boy, did it make a difference in the temperature of our laundry room.
Have you even noticed that the inside of the clothes dryer was colder than the laundry room?  Who would believe that this would make a difference.  But it does.  Our house is heated by a geothermal heat pump.  On one very frigid day, I noticed that the inside of the dryer was very cold when it was off overnight.  I looked into ways to prevent that heat loss from the laundry room and found an article about this vent.  It wasn't expensive.  It was easy to install.  And boy, does it make a difference!  I would highly recommend it to anyone who has noticed that their laundry room is cooler that the rest of the house.