Did they seal returns to the return chase in the walls?

[adamk]

I was in my attic and noticed that one of my return (hard) pipes moved a bit at the base.
I pulled the insulation back and noticed that the metal plate flexes a bit, allowing the pipe
attached to move a bit.

This house was built in the late 70's. Did they do any sealing of the return paths ? The
return I was looking at was between the wall and the 2x4's. It had a metal sheet
nailed down and the hard pipe coupled to it.

I wonder how much attic air it pulls from this set of connections.

Thanks.

[sktn77a]

Highly unlikely, unless it was an expensive, custom, energy-efficiency home.

[udarrell]

Pulling Return Air from a hot attic, happens much too often.
I saw it most often when Return grilles were under the air handler.

I was visiting a plummer who thought he knew a lot about A/C work & he always did his own work. He was a friend, but you wouldn't want to do work for him, if you know what I mean!

We were grilling hamburgers outdoors & I noticed the compressor was sounding like it was overloaded.

I walked over & the discharge air felt much hotter than normal.
I didn't feel of the lines; didn't want him to think I was getting too nosy.

He told me he had put in a bigger condenser as the other one couldn't handle it. He was also always, - way oversizing evaporator coils, ha!

So, when we went indoors, I walked over to the furnace closet in the hallway & opened the door. The blower would forcibly suck the door shut, ha.

The sheet rock was open (high up the wall, not sealed at bottom) to the area below the furnace & pulling hot air from the furnace area & attic. This is also very dangerous, as I don't see how the furnace could vent in winter.

I told him how to fix the problem, & to also enlarge the return air grilles under the air handler chamber.

I should have told him to take the oversized condenser out & match everything to a manual J. I figured he would realize the need for that, but doubt he knew anything about doing a load calc.

Using that big overloaded condenser, his electric bill must have been out of sight. I didn't want to embarrass him by asking.

Sorry 4 the long but true story. - Darrell

[dash]

Wall returns also pull a small amount of air past the drywall,from the adjacent stud spaces.

Usually you can see the the dust looking up the wall chase with a mirror and flashlight.

[udarrell]

Wall returns also pull a small amount of air past the drywall,from the adjacent stud spaces.

Usually you can see the the dust looking up the wall chase with a mirror and flashlight.
Yes, you're absolutely right Dash, all those air leaks need sealing everywhere; sometimes not always easy though.

However, his application wasn't using the wall as a Return; the wall just wasn't sealed high up, (wasn't sheet rock finished all the way up) & the interior of the wall at the floor of the furnace had to also be open.

Perhaps because it was drawing Return air well above the furnace vent intake it may not have been quite as bad. However, for it to pull the door to the furnace area closed; well that's a large negative down draft pull on the vent gas. - Darrell

[adamk]

Sealing sheetrock is definitely required.

In this house the prior owner had the plumbing fixed in a few areas.
They left holes in the sheetrock in the attached garage. I found out that
there was a lot of cold air being pulled through these holes.

So all they would do is just lay that metal sheet over the return chase and nail it down ?

Do they seal them now in the new tract houses ?

[dash]

Varies aroud the country,here in Florida you can't use a wall or floor chase,without a sealed duct inside of it.

[energy_rater_La]

No. in 1970 we were even bigger energy wasters than we are now.
Homes build in those times are not sealed or energy efficient unless planned and built that way.
Sealing your return is a great idea.
If you have insulation next to the top of the return, see if it is not dirty - streaked with dirt where the air is pulled into the return when mechanicals run. dirt trails will line up with leakage at return.
all leakage into attic at 2x framing members should be sealed, as should any plywood (in your case sheet metal) or sheetrock attached to 2x's.
sealing from attic and inside r/a would need to be done.
if you have a chase, it should also be sealed. sheetrock is for new construction IMO..too hard to fit it into a small existing return chase.
Ductboard is a much better choice and easier to way to seal these areas.

dust trails, dust/dirt build up and spider webs are inidcators of air infiltration.

Udarrel...I've seen many many homes that match your plumber's
situation.
What has always amazed me is that all thes years later since the original install... number of times these heating closets were opened and no one ever addressed the issue..or questioned why it was so dirty?
People tell me...its so hot here by the heating closet in the summer..wonder why??

y'all have a good weekend. tgif!

[udarrell]

No. in 1970 we were even bigger energy wasters than we are now.
Homes build in those times are not sealed or energy efficient unless planned and built that way.
Sealing your return is a great idea.
If you have insulation next to the top of the return, see if it is not dirty - streaked with dirt where the air is pulled into the return when mechanicals run. dirt trails will line up with leakage at return.
all leakage into attic at 2x framing members should be sealed, as should any plywood (in your case sheet metal) or sheetrock attached to 2x's.
sealing from attic and inside r/a would need to be done.
if you have a chase, it should also be sealed. sheetrock is for new construction IMO..too hard to fit it into a small existing return chase.
Ductboard is a much better choice and easier to way to seal these areas.

dust trails, dust/dirt build up and spider webs are inidcators of air infiltration.

Udarrel...I've seen many many homes that match your plumber's
situation.
What has always amazed me is that all thes years later since the original install... number of times these heating closets were opened and no one ever addressed the issue..or questioned why it was so dirty?
People tell me...its so hot here by the heating closet in the summer..wonder why??
y'all have a good weekend. tgif!

You too, Energy Rater, have some fun.

I'm so glad U pointed out ways to identify air leaks; that ought help many young Techs.

My advice to all contractors & Techs is to learn "Whole building air conditioning." U can do a ton of good for your reputation & 4 your customers.

I believe Duct Blasters & Blower Door testing tools should be made available at Rentals,& Govt ought to make them available for a low rent fee at the county level &/or at larger town levels.

There should be No slack season for HVAC work; I am working on Twitter to get broadcaster's involved in helping Govt reduce the tremendous waste of energy due to ductwork & lackof building weatherization.

Blower door units weigh around 50-lbs now & cost around $1500 & up. They are easy to use & prove to the customer they need some quick work done.

Then U verify with the Blower what has been accomplished. Those are great tools toward lowering utility bills. - Darrell