HVAC Duct-Not there

[thanley]

This isn't IN my garage, but above it in the chase going to the attic for the ductwork and vent for the furnace from garage.

I'm preparing to run structured media wiring all over the house and decided to venture into the wall that I knew contained all of this to see how the space was.

I made my first cut from the inside of the small closet in the hallway to keep the wife happy about not cutting holes in walls that won't be patched right away.

Anyways...I make the first cut into just the drywall and all of a sudden I have air blowing in my face. I cut enough drywall that I can see and I was shocked to discover that there was a peice of sheet metal about 5 inches in from the wall, but there was NO ductwork in the traditional sense. It appears this is the return air duct from the second floor/attic going back into the HVAC unit below.

The other ductwork in the area is all proper and sealed with no issues. Has anyone ever heard of this before? It's a new one for me. I've attached the best pictures possible given the small space at hand.

 

[1991Syclone]

What year was the house built? Our current house built in 65 uses the space between wall studs as the returns to the air handler located in the garage. There is no duct work between the studs, just a hole cut in the drywall with a vent covering it.

Our new house built in 1975 has the same return grates on the walls, and while I haven't taken any off to inspect, I suspect it's the same deal where they just used the cavity between studs for the returns. Since the air should be the same as the room temperature I don't see there being an issue with condensation.

Now if it was the feed line, I'd be worried.

 

[thanley]

It was built in 1990

after you said that I went and looked on the "other side" of the wall up high and I think that might be exactly it; the return air out of the master bedroom. will have to look fruther

 

[Bruce4310TX]

Yeh thats fairly common not right but common.