Condensation from ductwork

I was doing a mock inspection today and at the furnace (located in the basement) I noticed condensation coming from the ductwork and from the condensate drain.

It’s an old house, vapour barrier seems to be behind the finished part of the basement but there still is unfinished parts with CMU and with put vapour barrier.

What I noticed:

  1. condensate drain leaking onto the furnace
  2. improper tape for joints and lack of tape at others
  3. plenum condensating and also leaking air due to improper sealing
  4. I believe manual damper is severely rusted
  5. dissimilar material holding condensate drain line on concrete causing rusting which is leaking through the condensation line.

My question: is this condensation a problem ? (Minus the condensation leaking on the unit itself) It just started to get real hot here in Ontario Canada, and it’s an old house. My thinking is not a major problem and to monitor throughout the summer to get a better picture.

Thoughts ?

I disagree. It is a major problem. Water (no mater the source) must be controlled inside a home. This could also indicate other issues in the home or AC problems.

I was focused on the interior and when I went outside after I noticed the AC unit is well passed it’s life expectancy and shaking as it’s working.

You are right !!

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#1 enemy of a typical residential dwelling is H2O. Figure it out!


For learning purposes in my area it could be a poorly functioning humidifier. Do you have a better picture of this?

The humidifier attached to the unit is not functioning at all. So what you said makes sense !