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  1. #1

    Confused Musty cat urine smell from vents PLEASE HELP

    There is a musty cat urine smell coming out of my A/C vents and I am at the end of my rope. My landlord has tried several things to get rid of it, but to no avail. I desperately need help or at least to know where to turn next for help.

    In mid- April, the landlord had new cellulose insulation installed in attic. I come home to a horrible & very strong cat urine smell. Thinking that one of my cats has peed in the house (never happened before), I looked all over before realizing that the smell is coming from the A/C vents.

    For the first 2 days, it was unbearable all the time. Now it's just gross when you walk in & the A/C has been running, but you don't notice it once you've been inside a bit, so the apartment is liveable -- I just can't invite anyone over.

    What we've tried:
    -Cleaning the coils & drip pan (twice, I think)
    -Deodorizers (just combined the bad smell with a bad cover-up)
    -12-hr ozone treatment in the house
    -A/C inspection (not sure what they did, but they said no prob with A/C)
    -attic inspection -- no smell up there & no sign of vermin

    I recently bought one of those DIY home mold kits where you tape a petri dish to the air duct. A little bit of mold grew, but not a lot -- not sure if it's worth sending it in for analysis.

    I'm told that the A/C system is a water chiller system. I know nothing about A/C systems. I live in Dallas, and it's been a very hot summer, so the A/C has been on at least part of every day. Last year, before the insulation was installed, the A/C couldn't keep up with the heat. I live on the 2nd floor of a 2-floor building. The building is probably from the 70s, but I think the A/C system is more recent -- probably 10yrs old, which is when the current owners bought & rehabbed this complex.

    The problem with all the contractors who have come in to do work is that they walk in and realize it smells like cat urine, then they look and see I have 2 cats, and they basically assume that my cats are causing the problem.

    My cats have never peed inside. Their litter box is outside on the balcony. Most of the apartment has hardwood floors, but the hall (where the return vent is) and the bedroom have carpet. I have gotten down on hands and knees and smelled every inch of the carpet. I have smelled every inch of the whole apartment -- no cat pee smell. The smell only comes from the A/C vents. All of the A/C vents are up high, so it would be physically impossible for my cats to have peed on/in them.

    Please, please tell me where to turn next. Should I try for a duct cleaning? I hear that duct cleaning is a scam. I just can't live like this anymore.

    Thank you!

  2. #2
    Join Date
    Jul 2001
    Location
    Canada
    Posts
    1,818
    new cellulose insulation Had used it in a reno job we did in the office ( yellow stuff ) , ended up tearing it out to get rid of the smell. My suggestion would be NO smell before insulation , SMELL after insulation installed points to the insulation.

  3. #3

    Pretty sure it's not the insulation

    I'm pretty sure it's not the insulation. I spent the first couple month obsessing on the insulation, but I think we've ruled that out now.

    We sent a guy up in the attic to check it out -- he spent several hours raking and looking for an issue. He found nothing. Also, there is no smell in the attic.

    Apparently, this insulation did NOT have ammonia in it. It's just cellulose and borate -- nothing else.

    I think it may be coincidence that the insulation and needing the A/C (due to warmer weather) happened at the same time.

    Oh, and since I'm in a rental, I obviously can't take out the insulation.

  4. #4
    Join Date
    Feb 2001
    Location
    N.E. Iowa
    Posts
    314
    If you are really not sure it was your cat, get a black light (UV) and go over every ft² of floor at night using only the black light for illumination. Any urine will glow a kind of greenish color.
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  5. #5

    Black light

    I've done that already, actually. Nothing glows -- just some dust particles.

  6. #6
    Join Date
    Feb 2001
    Location
    N.E. Iowa
    Posts
    314
    The next thing I would suspect that is causing the odor is poorly insulated duct or register boots in the supply duct in the attic which is causing condensation to form and possibly pool on wood or drywall.
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  7. #7
    OK. I don't know how to check for that. What kind of professional should I call?

  8. #8
    Join Date
    Feb 2001
    Location
    N.E. Iowa
    Posts
    314
    I have cats and dogs myself and I know how people feel about them. They are like our children and the last thing we want to think is that they would do anything wrong, like pee in the house. LOL

    Before we completely rule out the cats I want to tell you of an experience we had with a couple of our cats. Evidently cats get jealous of inanimate objects, especially children's toys, and will urinate on them to show ownership. We couldn't figure out where the smell was coming from for a long time, until we finally started smelling everything in the room.

    We have another cat who, although he was neutered at 6 months of age, has been making whoopie with a fuzzy slipper every night between 10:00 and 11:00 PM for 16 years.
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    "We may have all come on different ships, but we're in the same boat now."--Martin Luther King Jr.

  9. #9
    OK, but the smell comes from the air vents, and there is no way the cats can access the air vents because they are up at ceiling level. The cats have no access to any part of the A/C system.

    If I leave the A/C off for a few hours, the smell goes away.

    I even hired a local company called Critter Control to come in and see if they could find the source of the urine smell -- he found nothing in the house. It's all in the A/C.

  10. #10
    Join Date
    Feb 2001
    Location
    N.E. Iowa
    Posts
    314
    If you have access to the attic you can look for your self to see if you can see any signs of condensation on the duct, duct fittings and register boots or if there are any signs of condensation pooling or dripping onto wood or insulation.

    If there is flexible duct you can look for areas where it may have droops in the run that could collect condensation inside and promote bacterial and mold growth inside the duct itself.

    If you aren't comfortable doing this inspection yourself a good HVAC tech should be able to check this for you in a short time.
    ______________________________________________

    Sign petition to limit Congressional and Senatorial terms. http://www.termlimits.org/

    "We may have all come on different ships, but we're in the same boat now."--Martin Luther King Jr.

  11. #11
    Join Date
    Oct 2010
    Location
    Florida
    Posts
    39
    Quote Originally Posted by myabigail View Post
    There is a musty cat urine smell coming out of my A/C vents and I am at the end of my rope. My landlord has tried several things to get rid of it, but to no avail. I desperately need help or at least to know where to turn next for help.

    In mid- April, the landlord had new cellulose insulation installed in attic. I come home to a horrible & very strong cat urine smell. Thinking that one of my cats has peed in the house (never happened before), I looked all over before realizing that the smell is coming from the A/C vents.

    For the first 2 days, it was unbearable all the time. Now it's just gross when you walk in & the A/C has been running, but you don't notice it once you've been inside a bit, so the apartment is liveable -- I just can't invite anyone over.

    What we've tried:
    -Cleaning the coils & drip pan (twice, I think)
    -Deodorizers (just combined the bad smell with a bad cover-up)
    -12-hr ozone treatment in the house
    -A/C inspection (not sure what they did, but they said no prob with A/C)
    -attic inspection -- no smell up there & no sign of vermin

    I recently bought one of those DIY home mold kits where you tape a petri dish to the air duct. A little bit of mold grew, but not a lot -- not sure if it's worth sending it in for analysis.

    I'm told that the A/C system is a water chiller system. I know nothing about A/C systems. I live in Dallas, and it's been a very hot summer, so the A/C has been on at least part of every day. Last year, before the insulation was installed, the A/C couldn't keep up with the heat. I live on the 2nd floor of a 2-floor building. The building is probably from the 70s, but I think the A/C system is more recent -- probably 10yrs old, which is when the current owners bought & rehabbed this complex.

    The problem with all the contractors who have come in to do work is that they walk in and realize it smells like cat urine, then they look and see I have 2 cats, and they basically assume that my cats are causing the problem.

    My cats have never peed inside. Their litter box is outside on the balcony. Most of the apartment has hardwood floors, but the hall (where the return vent is) and the bedroom have carpet. I have gotten down on hands and knees and smelled every inch of the carpet. I have smelled every inch of the whole apartment -- no cat pee smell. The smell only comes from the A/C vents. All of the A/C vents are up high, so it would be physically impossible for my cats to have peed on/in them.

    Please, please tell me where to turn next. Should I try for a duct cleaning? I hear that duct cleaning is a scam. I just can't live like this anymore.

    Thank you!
    What kind of ozone treatment did you use? Make/model/dosage during the 12 hours? I have had a few good results using ozone generators- especially after nothing else worked.

  12. #12

    For What ITs Worth:

    WE had a similar problem, but w/septic smell.

    1) New system installed in Jan 09
    2) We begin using the A/C part of HP in March of 09 and begin to smell septic smells throughtout the house
    3) We have a plumber to completely check everything out, its fine

    4) Finally, a lowly electrician installing a friggin ceiling fan (in attic) says, "your problem is that you condensate drainage pipe doesn't have a certain kind of pipe and its draining directly into the septic system.

    5) Tell installers what we've found, basically he tells me to GTH and its a plumbing problem...yeah his.

    6) So I fire my ass hole installer, and ask (very nicely) if the electrician would come and simply put a pipe to drain the condensate outside. Problem solved.

    Now your situation is different b/c you're smelling what seems to be urine. Is there anything type of gadget (wondering out loud) that can detect levels of ammonia?

    Otherwise, if its bad...you might just pay for new ducts and go from there

  13. #13
    Join Date
    Oct 2010
    Location
    Florida
    Posts
    39
    Quote Originally Posted by AvantGarde View Post
    WE had a similar problem, but w/septic smell.

    1) New system installed in Jan 09
    2) We begin using the A/C part of HP in March of 09 and begin to smell septic smells throughtout the house
    3) We have a plumber to completely check everything out, its fine

    4) Finally, a lowly electrician installing a friggin ceiling fan (in attic) says, "your problem is that you condensate drainage pipe doesn't have a certain kind of pipe and its draining directly into the septic system.

    5) Tell installers what we've found, basically he tells me to GTH and its a plumbing problem...yeah his.

    6) So I fire my ass hole installer, and ask (very nicely) if the electrician would come and simply put a pipe to drain the condensate outside. Problem solved.

    Now your situation is different b/c you're smelling what seems to be urine. Is there anything type of gadget (wondering out loud) that can detect levels of ammonia?

    Otherwise, if its bad...you might just pay for new ducts and go from there
    There certainly are handheld airborne ammonia detectors, but in your case it would probably be much cheaper to commission an Indoor Air Quality firm to sample the air in the area rather than purchasing your own device (which you'll probably only use once).

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