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Chemical Smell In House - Help!

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My wife and I recently purchased a home.......originally built in 1950's and remodeled in early 1990's. Half of the home is on crawl space and newer areas on slab. Two HVAC units service the house. My understanding is the older part of the house has metal ducts and the newer portion has flexible duct work.

The day we closed on the house we noticed a fairly strong chemical smell (bleach/chlorine like) in the house but chalked it up to the house being closed up.

its been 60 days since we closed and while i believe the smell is marginally better it is still lingering. so much so that you can smell it in your clothes after spending some time in the house.

We've had multiple professionals (including certified Indoor Air expert) look at the house and all are stumped. You can actually smell the bleach like smell at the front door before you enter the house and it's particularly strong in the foyer as you enter through the front door.

Here is what we know at this point......

1) One of the air handlers has a freon leak........we had more freon inserted and seems to be operating ok this point.

2) We've spoken to the prior owner and she claims she never used bleach to clean out the drain lines on the HVAC units (who know if she is being truthful). I know one of the drain lines is working ok.....attempting to find the other one to make sure that one is draining ok as well.

3) We had all the air ducts cleaned by a professional service

4) The smell does not appear to be emanating from the crawl space (we've had it inspected)

5) I've read articles about sewer gas smell but this is not a rotten egg smell ---- it smells very much like chlorine or bleach

6) We've cleaned the house with a light vinegar & water solution and aired it out with industrial fans........the smell continues.

Any thoughts on if the HVAC units or what else could be causing this? It's strongest in the foyer area but seems to be prevalent throughout the house. We're really frustrated and want to figure this out before moving into the home in the next 30 days.

Grateful for any thoughts, ideas or next steps......

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Refrigerant doesn't smell but the mineral oil on the older R-22 refrigerant systems does, but not badly and not normally like chlorine. I'd take the AC off the suspect list, except for the condensate drains.

Speaking of condensate drains, lots of AC's have that drain connected on the suction side of the AC cooling coil. If you don't have a functioning condensate trap fitting on it, the blower will suck air/gas from wherever the drain ends. That's usually either the sewer line leading to the street main or the septic tank, whichever you have.

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Since you're from Florida, did any of the professionals that paid a visit consider Chinese Drywall? It's gypsum panels contaminated with compounds that out-gas then go through a series of chemical reactions and ends up as acidic fumes that blacken copper lines and copper wiring of all sorts. May cause respiratory issues also if it's bad enough. The issue with Chinese Drywall peaked after hurricane Katrina/Rita (Aug/2005) when drywall suppliers imported it from China because USA producers couldn't keep up with demand.

Maybe some remod work was done in that foyer.


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A certified Indoor Air expert. Certified by who? You may want to try an industrial hygienist. They have real qualifications, which the certified Indoor Air expert may not have.

When you say bleach it makes me think that some mold remediation may have been done (not professionally). Have you tried to find if the smell is stronger at carpet, walls, etc.?

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Did any of your multiple professionals use an air sampler pump? They need to take multiple samples from documented locations and test the samples with potassium iodide. This will identify the area of highest chlorine concentration.

Then, surfaces in that area are swab tested with potassium iodide on starch strips to detect the residual chlorine.

If using the correct equipment and processes, the only way these professionals could be "stumped" is if it's not really chlorine causing the odor.

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could it be some type of growth on your coiling coils in the A/C?

I don't see how. Or even seen such.


Do a Google search for "Mold in Air Conditioning Coils" to learn about it.

look at this YouTube video:

It was just my guess but some funky odors can come from air conditioning systems. I was thinking that someone may have dumped bleach on the coils in an attempt to clean them.

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Nothing below smells like chlorine, but I deal with odor complaints all of the time, so I'll throw a few things out there.

Could it be an overcharged battery smell from a UPS system, alarm system, etc. ?

You could check for natural gas/ propane leaks to rule that out.

Was there any evidence of rodent activity in the crawlspace?

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  • 1 year later...

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