Mold in A/C duct? - Need some opinions

8 Replies

I will preface this post by saying that I am an Engineer with some experience on environmental matters.

Black / dirty air vents and ducts in my condo rental spotted by a prospective tenant expecting a baby.  I am not looking to cut corners or poor boy this problem.  I would not put any tenant in a potentially unsafe situation.

I am trying to get an understanding of how this is handled once it is confirmed that I have mold (if I do).  I expect there is a duty to fix and / or duty to notify but I don't know for certain.

This is a modest 1 / 1 condo with the A/C unit directly over the bathroom.  I expect part of my problem is the proximity to where people potentially take hot steamer showers.

Appreciate any feedback or war stories on this issue.

Thank you.

Are you sure it's mold? Or may it just be years of dust buildup?

I've had ducts cleaned before from an old oil burner that was spewing smoke for a while (pre-flip). It was a pretty easy project for a duct cleaning company and the house smelled better afterwards.

I don't know though if it is mold if it has to be handled differently. I know the company I dealt with advertised dealing with mold in the ducts, but didn't find out details.

At the metal air register is the coldest point from the unit mixing with hot/warm air causing condensation.  Continual condensation will cause mold, we run into this in our units.  I haven't been able to resolve our issues here either, but we on occasion once a tenant leaves is to pull off the register, scrape the texture, spray a 10-1 ratio bleach and water on the affected area, let dry and get a can of spray texture and then touch-up paint. 

Usually it is not a big area to do and takes roughly an hour total time.  If there is a solution besides moving the AC unit out of the bathroom, I am all ears.

Have you called a duct cleaning company.. that would be my first thought,, and second is to put in a switch where each and every time the bathroom is used, the vent fan goes on, this can be wired at the switch,, also I've sprayed Kilz in vents where smokers have lived and this has been helpful.. also consider a stronger motor in the bathroom vent fan and make sure the exterior vent opening doesn't have a bird's nest in it.. and is opening and shutting properly. 

As a follow up, it was mold verified by inspection and testing.

Fortunately, I had a friend who recommend a mold remediation company.  As it turns out, they were extremely knowlegeable, trustworthy, and reasonably priced.  I was absolutely terrified at first but picking the right company made all the difference in the world.

@Jay Dean , did they say how the mold started in the first place? I just got a call from a tenant yesterday complaining that the air coming out of vents has a mold smell, making his clothes and dog smell like mold. It's got a brand new furnace and A/C and it did take us a year to rehab and we, no any of the billion showings or contractors ever smelled anything and are mystified by what could be going on.

No.  He didn't say.

The first thing that I would check for is signs of moisture, leaks, etc.

@Jay Dean

What did it cost you to have the remediation company check it out?

An inspection including the sampling and analysis in a lab was $300.00

My remediation cost $750.00 but only because I opted to pay a little extra for them to spray an anti-microbial into the system.

I have heard a lot of war stories about these issues.  I think I was really fortunate to get referred to someone competent and trustworthy.

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