Before the deck was built this window was about six feet up. There was a small amount of demolition to do with the brick beneath the window.
An entry door will be an improvement from having to walk into the garage to access the deck. It will also be a thermal improvement over the two heinous single pane windows that leak air terribly and won't open and close anymore because someone painted them shut. Lovely!
|Hole in the wall|
So for the last 30 yrs hot and cold air has basically been venting to the exterior. Not that the gyp board provides much R value, but it's at least an air barrier. This probably means the registers on the other side of the room could be the same way. I demo'd this register and it's duct back to the y fitting and capped it off.