View Full Version : Strong urine smell coming from ducts
07-23-2005, 08:05 AM
We recently moved to Miami and purchased a house in March. When we had it inspected, the results came back that there was a mild amount of mold on the air handler--people reassured us this was common down here. As the air conditioning units were the original ones from when the house was built in 1973, we took the opportunity to replace both and also had the air ducts thoroughly cleaned.
Ever since we have been experiencing a urine-like smell coming through our air ducts. We have checked everything, including having the air duct cleaning company come back. No one seems to know what is causing this smell, but it is foul.
The smell is especially strong in our kitchen. The kitchen is on the ground floor, but the air vent flow is connected to the upstairs air duct. We don't know why it was set up this way, rather than on the downstairs unit. I am not sure whether this could be relevant. Occasionally we will smell the urine in the upstairs rooms as well.
I read on another posting about UVC lights and photocatalytic systems. Would these be potential solutions? Would a dehumidifyer work? What kind of service should we call to get this evaluated? Thus far everyone we've called hasn't a clue what the problem is and we are very concerned by this.
We have a 3 year old who has been suffering from a lot of
respiratory illness since we moved here, although I don't know whether it has to do with our house or his preschool....
Thanking you in advance for your help with this
07-23-2005, 08:27 AM
Originally posted by ezhfjs
Thanking you in advance for your help with this
Get a hand spray bottle(like an old windex bottle)
make a solution of 4 parts water 1 part bleach to spray into air the ducts airstream.Try to avoid spraying mist through the blower at first.Enter downstream,after blower.
See if that works.....If not,then try a fine mist through the blower.
This is a cheap and easy solution.It sometimes is all you need.
I don't totally agree with jacob. I would under no circumstances spray bleach into the duct. But I would take that same bottle with plain water and then mist the coils, turn the fan to on and see if the smell starts if it does that should mean the odor is from the coil. The duct cleaning company should have cleaned these ask them to clean them again.
07-23-2005, 10:36 AM
Being as you are in Florida, and that Florida uses flex-duct exclusively, you have critters living in your duct system. Hire an exterminator first, then have your ducts repaired. Rat or mice or other pest feces are probably the cause of your kids problems.
07-23-2005, 10:49 AM
Originally posted by ezhfjs
As the air conditioning units were the original ones from when the house was built in 1973, we took the opportunity to replace both and also had the air ducts thoroughly cleaned.
Yes I misread...."replaced units".ductwork is still unchanged,though except for cleaning .I am guessing it is hardpipe.(When did flex become the norm? 1968? 1978?)
No I wouldnt spray anything in newer units,I would if they were the the 1973 models,though.
I would get rid of that smell though.
07-23-2005, 12:57 PM
We have fiber ducts (is that flex?)
Regarding the post on rats or mice, I'd expect that we would hear them if we had them? Also, we did have the ducts cleaned so I am presuming that they would have found any rats or mice then (at least I am hoping so). The duct cleaning company is coming again this week so I will ask them to double-check. I learned also that because they had difficulty reaching the air duct leading to the kitchen, they cut it open and re-sealed it. Could this have something to do with our odor?
In the meantime if anyone has advice on how to get rid of the smell, I would be so grateful - it is becoming more and more unpleasant
07-23-2005, 01:02 PM
you have to get rid of the source (vermin) before you get rid of the smell. trust me on that. hire an exterminator first
Fiber duct ( duct board ) Did the cleaning company coat these? Duct board needs to be coated after it is cleaned! Foster 40-20 is probably the best you can buy.
07-24-2005, 11:44 AM
I greatly appreciate these suggestions - i hope we are getting somewhere with this
I checked and the company that cleaned our duct work did not seal it afterwards. In fact they mentioned that they may have damaged parts of the ducts as there was physical rubble and all kinds of junk that came out when they cleaned them. Plus, as mentioned, they did have to cut one part open so that they could get to it and clean.
If the ducts are unsealed, does that mean that moisture is collecting in the fibers and possibly causing the nasty stench?
If we hired them to come and seal it, could that be all that is needed to solve the problem?
Is that an expensive process?
tin_fab and outside rep -
I have also called an exterminator to come next week and check for vermin--yuck. What are midgets?
I'll keep you posted as we find out more...
Yes moisture can and will get into the duct board! Plus the fiber glass will erode. I can't belief that they did not quote to coat the duct board after cleaning ( this is a no brainier ). Make sure that the coating is an EPA approved coating! Not just one chemical but all the product! Make sure it has an antimicrobial inhibitor in it also. I have seen wet insulation to cause an odor before. Is this your problem? only time will tell. But Duct board should be coated after cleaning smell or no smell. GOOD LUCK!!!
08-01-2005, 06:55 PM
dont let the cat play in the ductwork
08-04-2005, 09:56 PM
I had the house inspected twice and while we have termites, there is no sign of any vermin living in our attic. In fact most of the openings to the house are well sealed
I had the airduct re-cleaned. The company said it did not make sense to seal it because it takes too many turns in going from upstairs to downstairs and they would not be able to adequately reach it.
For now I am running an ozone machine in the hopes that the smell goes away (so far, no good)
My final guess is that there is dampness in the airduct causing the urine-like smell. It's a fiber duct
Would we have to do something as drastic as replace the air duct to get rid of the smell? We are only planning to stay in the house for another year or so...
Watch that ozone! Ozone is a pollutant. It can be very dangerous! Take a look at EPA web site. If you are only going to be in the house for one year I don't think I would replace the duct. Your duct cleaning company should be able to get to most of the duct to coat it.
08-05-2005, 08:39 PM
urine smell, yuck! had my truck in the shop after my girl wrecked it, left the windows down and cats pissed in it. ozonated it and smell went away.
however my concern to the manager was not the smell, its the odor causing agent and any other properties it has. something to think about
If you sell the house knowing that the ductwork smells like urine, you might have to end up paying to replace the ductwork anyway (lawsuits), plus "pain and suffering."
I may be all wet, but....
Having worked with fiber duct board once, (once too many), I seem to recall the strong odor when cutting through the material. I would suggest that you visit a local "ductboard using" contractor and see if the odor isn't from freshly exposed areas of your duct. You might not use the contractor who cleaned your ducts, though. Savvy?
08-15-2005, 08:53 PM
Thanks for that idea - if I do consult the other contractor, what would be the remediation for the fact that the ducts were cut through.
By the way, the smell has lessened and changed
08-15-2005, 11:55 PM
you said that the smell has changed, in what way did you change the cat's diet recently
09-23-2005, 09:18 PM
Ok I got to know...
how did the smell change?
BTW you or previous owner didn't
ahem,.. p*ss off the installers did you/they?
I hope your child's health is not
suffering & that your problem is solved.
But really, let us know!!
09-26-2005, 02:58 PM
I don't think any type of sealant will do any good, that's the smelly problem, the fiberboard. I remember installing spacepack & unico systems with that fiberboard (round pipe) it was brand new and boyyy did it smell like piss! We were still told to install it. I'm sure glad they changed to rigid metal for the trunkline. Looks like you will have to replace that smelly ductwork. :(
Coat it with a good coating and it will be fine
09-26-2005, 10:28 PM
Originally posted by drk
Coat it with a good coating and it will be fine
Go back and re-read OP's update.
09-26-2005, 10:39 PM
Do you or did the previous owner have Ferrets
See condenseddave he is an expert on this subject:D
damn polecats, do a search on Ferrets
10-03-2005, 12:35 AM
It sounds like the problem is in the duct going to the kicthen. Is this where the smell is still the strongest? If you get some cooler weather you should try shuting off the unit that supplies the upstairs and kicthen for a day or so and see if the smell goes away. Then run just the other unit and see if there is a noticeable difference. I would experiment like this and try to isolate the problem.
Duct cleaning is one of the biggest scams I have ever seen. Homeowners can't see inside their ducts and herein lies the problem. With such a great open market to scam there are hundreds of outfits that spring up. There are a handful that do it right and the odds that you have found one of them is slim. Don't get any more duct cleaning done, your just throwing money away. Your money would be better spent towards a contractor that specializes in IAQ and is willing to solve your problem.
How long did you live in the house before the units were changed out and did it smell then?
You said the smell was foul, then it got worse, and now it is less and has changed. This sounds like a decaying animal to me. I remember a job I went on years ago that was somewhat similar. It was a peace and police officers association building in the city. The secretary told me when I arrived they had a bad smell in the building for quite some time but lately it has been worse, especially when the A/C is running. I checked out the roof top unit in question and couldn't find the source, although a slight foul smell did linger. I started walking around the inside and determined the smell was worse in the conference room. I lifted up many ceiling tiles until I came across an area that was pretty foul. It was near a steel pole which supported a main support beam of the building, and it was cased in on all sides by sheet rock. There were many anti smell canisters placed around it but apparently no one else who had come out to investigate the smell took a peek down this incased area. I stuck my head over it and looked down and saw the biggest rat I have ever seen in my life. I had no idea they could get that big, it was dark because it was above the ceiling tiles but I could see the outline of the body and the rings on its long tail. And once I had my nose right over the thing it was the foulest thing I have ever smelt to this day, worse than changing a diaper. I have no idea how this rat of this size got in, but it must have been crawling around on top of the ceiling tiles, fell into the encloser, and couldn't crawl back up and died.
My point is that the smell may seem like it comes from the ducts, but it could be something dead and hidden else where. Even my big nose had trouble finding that dead rat, took the better part of the morning. The ozone machine is just a band aid you still need to find the source. Good luck in your search for the smell.
10-24-2005, 11:55 PM
What happened?! This was like reading a mystery novel...I'm dying to know what the final outcome was!
10-25-2005, 10:29 PM
When you bought the house, did it smell when the system was running?
Fiberglass duct is made with a thermosetting resin(glue) that has urea as one component. When it is used in the correct amount, distributed evenly through the matrix of the board, and dried COMPLETELY, there is no problem. When it is used too heavy, concentrated in the matrix, and/or left too wet from the factory it smells like --- URINE (and several other unpleasant descriptions I have heard).
Another reason for fiberglass duct smelling may be that the system is introducing moisture from the cooling coil onto the surface of the duct. There are times when the air velocity through the cooling coil is too fast and condensation will blow off the coil, onto the duct surface, soaking the duct surface. Another one I ran into was a drain pan that was sloped away from the drain opening. The condensation that was supposed to be running out the drain couldn't and overflowed from the coil drain pan onto the duct surface. That house really smelled bad!
Solution if the duct board is wet, is to replace the duct. Don't let anyone tell you it can be dried successfully for the long term. If the condition were stopped very early in the beginning of the problem, this would have been possible. The drying process would have had to happened quickly. What has happened by now, is the conditions for mold and/or mildew growth have existed for too long, and it is time for the wet portions of the duct to go.
Do not apply top coating products that the manufacturer of the ductboard does not supply. These top-coatings/sealants may deterioriate the resins and cause lots bigger problems than you have now. To identify the manufacturer of the board, look on the outside of the duct. Every piece of board is made with this information on it.
10-25-2005, 10:45 PM
who pissed in the ducts ? have that crap replaced with metal.
11-01-2005, 01:51 PM
My neighbour once asked me to look at his hi-boy furnace because of a real strong urine smell coming out of it. Turns out his two little boys were using the control cabinet/burner deck as a latrine. Yes, the urine ruined the deck.
11-16-2005, 08:38 PM
im gonna go with rats if not look and see what the shape of your coil is if youve had your ducts cleaned recently call them back they should have cleaned the evaporater coil
i have seen where returns located near kitchen will get a good coating of grease through the system it smell like pee when it gets old
11-16-2005, 08:43 PM
it was me i like top pee on customers units this way i can get more work and the istant relief
11-17-2005, 10:11 PM
inspect the duct for damage by vermin. It is always pretty obvious where they chewed their way in and leave a traffic trail. If there are no openings, there are no vermin so look elsewhere. IMHO
01-15-2006, 09:18 AM
my first question is: Is your son peeing in the air duct? (I've seen this before) or how about a pet? (seen that too) Also any time you have mold resident in your furnace, coil or air handler it is in you whole system. The whole thing needs to be treated more than likely it would be better to replace the whol thing installing a air cleaner and a UV light installed below the coil.
01-15-2006, 06:24 PM
Odors = volatile organic compounds or other chemicals that you are smelling. The source of the VOCs might be mold, urine, decaying organics (dead stuff), bacteria, or off gassing from the chemical compounds in building materials. UV lights don't do anything for VOCs and can create a potentially hazardous situation from breakage. Actually effectiveness on "killing" microbials such as mold and bacteria depends upon dwell time and intensity. Too much of the exposure to UV radiation can be bad for plastics. Carbon filtration may remove VOCs from the airstream but don't do anything to eliminate the root cause. Oxidation of compounds, whether they be VOCs or nanoparticles such as carbon black, based on University research results reduce the toxicity levels significantly. EPA findings on Advanced Photocatalytic Oxidation processes in their 1998 Handbook help to explain why Photocatalytic Oxidation reduced and virtually eliminated VOCs.
Ahhhh dont you love the smell of strong urine in the morning?
Why did this old thread get bumped again? I need to get off the mailing list for this one! :)
01-29-2006, 11:15 PM
I have lost track of this thread, but wow, thanks for all the input.
Embarrassingly this issue still has not been solved - partly because the uriney-damp smell comes and goes and partly because I am not sure what path to take to getting this solved. Given that the smell is bad again (the air conditioning is currently off) I really need to get this fixed!!
We had the house inspected multiple times for mold and vermin and even tented it so the smell is definitely is not peeing or rotting vermin. I've also made several calls to ask about having the air ducts sealed but as I am not even 100% certain this will solve the problem, I've been reluctant to throw more money at the problem...
H&C Guy mentioned damp fiberboard and I was thinking some more about this:
The foul smells come through the air duct in our downstairs kitchen. Due to some bizarre construction, the kitchen is the only downstairs room that is cooled by the upstairs ducting system. The upstairs duct travels via the master bath and twists its way downstairs to the kitchen. Currently the master bath does not have an extractor fan to remove moisture.
Could it be the case that the dampness from the bathroom gets caught in the twisting duct and causes the foul odor downstairs in the kitchen?
If this could be the cause of the problem - what do we do and who do I call to fix?
Thanks and I hope that my next posting is to tell you this has been solved
02-01-2006, 11:17 PM
had this same problem with one of my customers rental houses, turned out it was the son weeweeing in the vents, check your vents(supply & returns) and see if they have rust on then, and will probally find you have the same situation. Funny thing about it was they moved out and the weewee smell moved out too
“Tell me and I forget. Teach me and I remember. Involve me and I learn.”
04-06-2006, 11:59 PM
an old thread i know but a new idea..i dont think it was mentioned hps or furnaces but the smell could always be coming from a drain..if mains are dropped into a plumbing stack instead of outside and are not down into the water then with the negative pressure of a heat pump the smell could be sucking up through the drain pipe and into the unit..mold grows in the plumbing stacks as they dry out over the winter when no water is coming trough..if the drains are ran outside they could still have mold in them especially if there is any part that is level or ran up hill..surprised no one mentioned drains before..ive ran into several times and it smells pretty bad
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