This site is the best, so I'm hoping someone can help me out with a major problem I just discovered with my forced air HVAC system.
We've done major reconstruction over the years to our home which involved rerouting of supply and return lines. This rerouting was often not done in a very efficient manner.
My recent discovery was that our HVAC guy created the return in one of the bedrooms, on an outside wall. The old return ran through a downstairs wall that was moved so he moved the return. Unfortunately, for the new return, he basically just removed the existing blown insulation and used the stud bay as the return. Thus, between the bedroom and the outside air is just the grill, exterior sheathing, layer of the old shingles, and the siding. Even worse, some of these materials are cracked/broken to the point where last night I could even see a glimpse of my neighbors light from the bedroom. No doubt I am losing tons of warm air to the outside. Not good! I taped up the pinsize hole and cracked areas with a good mastic tape but it's still a bad situation.
Thus the question... is it better to leave it as is which means I have a return but an entire uninsulated bay which gets directly hit by the NW winds we get OR better to close off that return and fill the bay with insulation?
I know an efficient forced air system relies on the returns but it pains me to be throwing money away in heating costs with such a huge uninsulated bay which allows air flow to and from the room via the return grill.
I am attaching two pics. The first is the grill. The second is the view from the outside. The uninsulated bay runs along that narrow vertical piece of the house. See my artistic red lines. You can see the bedroom window to the left.
Thanks in advance!