Calling HVAC experts

[944 S2]

While redoing my plumbing in my master bathroom I opened up the flooring to discover an HVAC line not connected to anything and air is passing thru it!
It’s located above the garage in a large dead space. Surely this can’t be right. I can’t imagine someone thought it a good idea to heat and cool the dead space, unless it’s an attempt to prevent frozen pipes in winter?
Thoughts? At this point I’m considering to simply add another vent since it’s a pretty good size room.

[cabmandone]

Is the space between garage ceiling and the room floor adequately insulated to prevent waterlines from freezing?

[Evans, Marv]

Looks like black plastic (ABS?) pipe??? Can't imagine a reason to terminate an air outlet like that. Condensate line???? If it is indeed a "duct" from the HVAC, you could certainly install a vent you could shut off when you didn't need the air. By the way I'm far from an expert.

[cabmandone]

^^^^
Nope... insulated flexible duct.

[944 S2]

I believe it’s adequately insulated. Here’s a picture of the space.

[Evans, Marv]

Wow!!

[cabmandone]

I'm going to get into a few more things here. Are you in a rural area of Ohio where the wind blows nice and hard? Does your exterior have wind barrier? Vinyl or Brick? Reason I'm asking is, insulation stops the heat transfer but won't stop the wind. On a cold wind driven day that space could potentially get cold enough to allow the lines to freeze. You could put heat tape on the lines and terminate the duct in the space you want to heat if you make sure the lines are properly freeze protected. You could also change out the lines to Pex that has greater ability to expand without bursting. My guess is someone thought that was a way to keep the lines from freezing.. Wouldn't be how I'd do it... but I suppose it works.

[cabmandone]

What's that stub wall the joists above the drain line open to on the other side? More garage ceiling?

[944 S2]

Originally Posted by cabmando

I'm going to get into a few more things here. Are you in a rural area of Ohio where the wind blows nice and hard? Does your exterior have wind barrier? Vinyl or Brick? Reason I'm asking is, insulation stops the transfer heat transfer but won't stop the wind. On a cold wind driven day that space could potentially get cold enough to allow the lines to freeze. You could put heat tape on the lines and terminate the duct in the space you want to heat if you make sure the lines are properly freeze protected. You could also change out the lines to Pex that has greater ability to expand without bursting. My guess is someone thought that was a way to keep the lines from freezing.. Wouldn't be how I'd do it... but I suppose it works.

I’m in a Columbus suburb. House is basically stucco outside. The cold exposure is really from the garage ceiling.

[944 S2]

Originally Posted by cabmando

What's that stub wall the joists above the drain line open to on the other side? More garage ceiling?

Garage pic

[cabmandone]

Okay so no real wind load. I'd still feel safer having some sort of freeze protection on the lines. When we get those cold snaps, waterlines in unconditioned spaces tend to freeze up.

[944 S2]

Originally Posted by cabmando

Okay so no real wind load. I'd still feel safer having some sort of freeze protection on the lines. When we get those cold snaps, waterlines in unconditioned spaces tend to freeze up.

I hear ya!
So that’s my dilemma, is the open HVAC line deliberate or mistake? For sure it would pump warm air in so if I divert it to another vent I would loose the thermal effect it currently has. Just seems very strange to do it that way.

[cabmandone]

I think it was done deliberately to prevent frozen lines and potentially to prevent cold floors in the winter. It seems odd to me as well but I could see why they'd do it. How many vents are in the bathroom currently?

[944 S2]

Originally Posted by cabmando

I think it was done deliberately to prevent frozen lines and potentially to prevent cold floors in the winter. It seems odd to me as well but I could see why they'd do it. How many vents are in the bathroom currently?

I leaning toward not touching it for the reason you mentioned. There is currently 1 vent in the bathroom.

Now I think I can keep going!

Thanks to all who gave input....you guys are awesome!

[cabmandone]

If you can track the line back to the main trunk you could put a damper in to stop the flow of air during the summer and turn it on in the winter to heat the space.

[eastbay]

Someone f'd up and forgot about it.
It was either for a vent in the room you are working on or for the garage. Your choice on where you want to put the vent.


but, but, but, are you sure it is hvac inside air it is pushing? Not exhaust or fresh air intake? Better trace it back to make sure.

[A930Rocket]

After many complaints about hot/cold bonus rooms over the garage, we added a vent to the space between the two at one house. Never did hear how it worked out.

Insulating the garage walls/ceiling and insulated garage doors works well I keep the bonus room comfortable.

[T77911S]

if it gets hot in that space it could cause condensation. had it happen to me after my HVAC install. they left a small leak in one of the ducts and it dripped water on my ceiling,.

is there a vent in the bathroom they forgot to put in?

you could vent it to the garage. I had one added to my garage in my old house.

BTW, that's pretty fancy have a a finished ceiling like that in a garage.