Water dripping from air conditioning supply vents
Hello I thought I had figured this out pretty easily the first time I noticed it.
There was a small puddle at the corner of my bed that I though might have been one of my lovely male pups leaving a present. As I was going to clean it up, I got hit with a drop from the air conditioning vent in the ceiling.
I chalked this up to my wife taking a shower in the master bath without running the fan. We tend to have higher humidity in our master bedroom because my wife prefers the door shut and rarely uses the bathroom fan during showers. I figured some warm moist air condensed.
Today however I noticed this happening in my living room. I checked the humidity in there and it is only 29%, yet I have water dripping at a pretty good rate from another ac vent. The water has been on the supply side vent in both cases. When I remove the vent, I can definitely feel cold outside air as they didn’t seal any of the venting. The AC was installed 8 years after the house was built, before I moved in, and was a crap job in my opinion.
Any ideas or suggestion to help with this? The attic is un-conditioned, and partially vented with R-4 or R-8 pre-insulated flex ducts. The original insulation installer decided to pack some of the soffits full of fiberglass.
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Replies
Mike,
Where are you? Is the weather hot, requiring you to run your air conditioner now?
Or is the weather cold, requiring you to run your heating system?
Mike,
If your weather is hot, and you are now running your air conditioner, then humid outdoor air is somehow contacting cold components of your duct system.
If your weather is cold, and you are now running your heating system, then humid indoor air is somehow contacting cold components adjacent to your HVAC grille.
Martin,
I'm in Zone 4, near St. Louis. The weather is in the 20's-40's around now. I have not used the AC system since August or September. I use my wood stove and solar gains as the primary heat sources. I am the lucky guy with the 6" slab on grade hydronic floor heat system that was not insulated, so I have shut the breaker off and don't even mess with it at this time.
I should also note the plastic inside of the flex duct was also wet from condensation. Would it help to just run the fan every once in a while to get the humid air out of the vents?
Mike,
So the ducts are in your cold attic. Warm interior air is rising through your ceiling grilles, encountering the cold ducts. The moisture in the air is condensing on the ducts.
Ducts don't belong in unconditioned attics, as you probably know. Here are links to two articles to tell you what you need to do:
Keeping Ducts Indoors
Creating a Conditioned Attic
Thank you Martin, I was hoping this was not the case.
I am trying to find a local HVAC contractor that will look at my plans for putting in some mini-splits to heat the home and cool it when I do an addition this spring.