Installed a new furnace humidifier to replace a non-working(probably never used) vintage humidifier 14 days ago in a new place I bought.

Confirmed a small gap let a slow drip from condensation that is now visible in spots near the bathroom ceiling(discovered wet spot 1 day ago. Didn't notice spots when replacing bathroom lights 3 days ago so likely very recent).

Wood floor/ceiling in furnace humidifier crawl space above bathroom shows moisture in some areas but it dries pretty quick(it's hot/dry in that tiny room but seeped down floor cracks and wall opening: no permanent warping of wood or even long term moisture marks despite being slowly soaked regularly for 1-2 weeks). Some small yellow water stain damage on wall next to furnace near

Photos: https://photos.app.goo.gl/iHwGydbetBBoZ3ku8

FYI: the white spots in the wood floor are from saw dust. There is no visible yellowing/dirt on the drywall and it seems to be rigid. Moisture was more visible but turned off humidifier last night(dried very quickly).

I'm getting a mold test pronto, humidifier turned off, sealing the ductwork gap, dehumidifier(?) but worried about long term mold risk and if I should get mold inspection? Do I even need a dehumidifier rental for the bathroom if humidity in my place to 15-25 without the humidifier on? Wood has dried completely in a few hours already.

I use an ecobee thermostat to control the humidifier/furnace so below are stats:

Humidity in the place has never risen above mid 50s(all window corner unit in chicago winter) and usually hangs around 35-48(according to sensors) for the past 2 weeks. Max I've seen it ever is 53(temporary after shower or dryer was run). The bathroom has a humidity sensor controlled fan that turns on for 30 minutes if humidity ever hits 60%+ in the room. Indoor temps hover around 63-75(58-63 at night and most of day when away; 68-75 when at home).

EDIT: My furnace air filter is rated MERV 10(installed 2 weeks ago) so most mold spores if in the air were likely caught

  • 1
    What's the question, exactly? Mold spores are everywhere, floating around in the air. Some probably grew somewhere, and it's probably not an issue if things are dry. – isherwood Jan 20 at 17:33
  • I would race to the store and get a mold test only if you want to wast your $. I agree with Isherwood and any spots you see may dry out fine in a few weeks. Even if there is mold most are not a health problem, het some hydrogen peroxide if you want to do something, 3% hydrogen peroxide and water will kill mold, I always have a fresh quart of 30% great stuff and no stink like bleach has. Just remember always add acid when mixing to prevent an exothermic reaction. – Ed Beal Jan 20 at 19:17
  • The small dimple in the photo looks like a screw that was not properly mudded, the large wet spot may take 3-4 weeks to fully dry don’t mess with it, possibly have a fan blow across that area. The Sheetrock may show a stain from the wood and dust in the floor that the water picked up if it takes a month to dry wait another month if you want to paint. – Ed Beal Jan 20 at 19:30
  • @isherwood, how badly is the screw up? Based on comments, not so bad to ruin my walls or worry about mold everywhere.. I can't believe an HVAC guy did the duct work for the old humidifier so bad: Massive gaps everywhere. – deek Jan 20 at 20:56
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