[rhagfo]

Originally Posted by mikec557

There are several good YouTube videos.

The attic space: it's the space between the outside rooftop and the inside ceiling. I'd guess it's about 5-6 inches tall. You see the foam air duct? That is in the middle of the height of the attic. See too how it's laying on top of a 2x2 piece of wood? Cold air blowing from the air conditioner can, and will, blow through that narrow gap into the attic instead of all going into the foam duct opening. The factory did a crummy tape job. Part of your gap is sealed, but not all of it.

This is how they taped mine. Lot of nice tape but they completely missed sealing my air duct.

In the second pic, of the bedroom vent that is pre-wired for a second air conditioner, I placed my first piece of tape. The piece of tape is about 1-1/2 inches into the duct, then spans the air gap between the duct and the 2x2, and then is taped to the 2x2. Tape is maybe 4 inches long? Overlap each piece of tape by at least a 1/4 inch.


HVAC tape from Home Depot or Lowe's or True Value, etc. Buy the bigger of the two size rolls. It can be a little difficult to work with and the big roll is only about $10.

Two great pictures of how poorly the factory does the sealing!
Once done correctly the duct opening should be the only opening visible. As stated before I also sealed my intake side so as to not draw hot air from the roof space.