Anonymous wrote:Modern high efficiency gas furnaces have two pipes to the outside - an air intake pipe (so it doesn't use your heated air) and an exhaust pipe. Neither should be venting inside.

Could be a pressurized condensate drain from when it's running A/C:

https://hvac-talk.com/vbb/threads/2183801-Condensate-drain-line-blowing-cold-air

Our HE furnace has a condensate drain for both heating and cooling. It goes to a pump that is pumped through a tube into our set tub.

Modern high efficiency gas furnaces have two pipes to the outside - an air intake pipe (so it doesn't use your heated air) and an exhaust pipe. Neither should be venting inside.

Could be a pressurized condensate drain from when it's running A/C:

https://hvac-talk.com/vbb/threads/2183801-Condensate-drain-line-blowing-cold-air

Anonymous wrote:Do you have this outside? One is intake the other is out. Standard for new high efficiency furnace

Also I saw this set up for a drain which I don't have but looks ok

Do you have this outside? One is intake the other is out. Standard for new high efficiency furnace

Also I saw this set up for a drain which I don't have but looks ok

Can’t understand your situation from your post. Do you have a passive radon system which is just a PVC pipe

Make sure you have a carbon monoxide detector nearby as step one, then I would get an hvac person to look at it.

That doesn’t sound right. Mine doesn’t do that.

Had a new furnace installed and noticed that there is some PVC piping that vents into the house where hot air comes out. I don't remember the prior furnace having that. There is definitely a vent to the outside where hot air goes, but there is also a pipe coming out of the side that goes down into a condensate pump drain but the top of that pipe is open and blows hot air. any idea if that's normal?