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condensation through ceiling

Ok, I think I originally posted this in the wrong place, so I am re-posting it here. Please excuse the double posting.

Hi. Can anyone help me? There is so much condensation on my ductwork (throughout the house) that I have had to rip out the basement ceiling due to water damage and mold(ugh), and have recently come home to find the ductwork between the ceiling and floor of the upper two levels leaking through the drywall and paint of the main floor ceiling. It had been very humid for several days when this occurred and I have not experienced rain in my living room since--knock on wood. However, the problem was occurring in the basement for some time prior to my first noticing it in the upper levels, and may well have occurred in the upper levels previously, too, only to a lesser degree than recently.

I have a heat pump that is correctly sized for the house (don't know about for the ductwork), with a clean coil. In fact, the coil seems too clean given the condition of the ducts (dirty). The entire house has been poorly maintained for at least nine years prior to my purchasing it, and probably for its entire lifetime (~30 yrs). The heat pump is approaching the end of its life (both indoor and outdoor units). I believe the system is 10+ yrs old, which is another reason the cleanliness of the evaporator coil is so surprising (the previous owners were NOT the coil-cleaning type), but it still does its job.

Any suggestions as to why there is so much condensation and what I should do about it? Do I need to replace the entire HVAC system, including the ductwork? Any relevant insight/advice/suggestions would be MOST greatly appreciated. Thank you in advance!


  • jeff_51
    jeff_51 Member Posts: 545
    I would suggest that the unit is over sized

    and not running long enough to dehumidifie the house. How long does the condensor run befor it cycles off? Should run around 50 minutes out of every hour. I "undersized" my unit by 1/2 ton from what manual J said and it runs great untill we get sustained temps up in the high 90's. The easiest short term solutuon is to get a dehumidifier in the basement and run it continously, maybe even two. HOw do you know the system was sized properly. Also, are you letting the system run continously? or are you using a sver switch or setting back during the day? I may be in the minority here, but I DO NOT ever use saver switches( they short cycle you ac something awful, and unless you are gone for more than eight hrs, you are not saving a thing by setting the system back. Keep it at 75 and let her run
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