Did someone pee on my A/C?

August 23, 2006 5:35 AM

My window air conditioner smells like pee when it's on. There is a roof deck immediately above this window. We are on good terms with the tenants up there, but they have guests over pretty often.

Last night, upon turning on the air conditioner fan to drown out the sound of a car alarm, I was assaulted with the smell of urine. (If this isn't a sign to move out of the city, I don't know what is.) It is not coming from outside or inside, and I can only smell it when the A/C fan is running.

1) Is this something guys do now, going all R. Kelly on A/C units? I'm sure it wasn't an act of revenge, but it could have been some random guest acting out while the hosts were away.

2) How do I clean this? Whether it's pee or not, the smell has got to go. I was thinking of pouring warm soapy water in through the vents on top. Any reason that wouldn't be safe? Any better ideas?

posted by Doctor Barnett to home & garden (19 comments total)

I know there was a previous AskMe in which someone suggested spraying Febreze on the filter of a smelly air conditioner. It's probably worth a try.
posted by Faint of Butt at 6:19 AM on August 23, 2006

Faced with a similar problem (dead rat, furnace) I bought one of those "odor killer" products and threw some into the intake manifold of the furnace, and it got it.
You can identify the products because they'll say something like odor killer or smoke killer on the can, and they all smell the same, because it's the same chemistry. Warning: The chemistry involved here smells nasty all by itself, but it it will get the stink in a couple of days, probably. You can run it while you're out if you like. Something in the chemistry beats up the odor molecules. By pulling it through the AC, it gets into everything inside.
posted by unrepentanthippie at 6:23 AM on August 23, 2006

There was a thread a few days ago that might have some helpful tips, although it was about smoky smells rather than peey smells.
posted by bcwinters at 6:23 AM on August 23, 2006

When you say urine, do you mean amonia, or something more, uh, vibrant?
posted by Kid Charlemagne at 6:24 AM on August 23, 2006

There are also bottles of urine remover sold for cleaning up after wayward pets. Considering that wayward party guests are a mere order of existence below pets, a bottle may work for you. Check with your local pet supply store for a wealth of options.

I have no idea if the stuff will gum up your AC, though. I'd give your neighbors the heads up about their guests and how uncool it is to sit and chill in urine-stank.
posted by robocop is bleeding at 6:25 AM on August 23, 2006 [1 favorite]

It's probably worth trying to just inundate the thing in place using a hose. If that doesn't work, you're no worse off.

I had a similar problem from birds roosting on top of an AC unit. I pulled it out (into the apartment), put it in the bathtub, and hosed it down. I took the cover off before I washed it. You might be able to irrigate it sufficiently through the vents, but it's not a lot of work to remove the cover. Note that AC units are big, heavy things, with sharp corners. If you are not strong, don't try pulling it out. If your bathtub is plastic or fiberglas, don't put the AC in it; you'll scratch the tub.
posted by Kirth Gerson at 6:27 AM on August 23, 2006

And for the first question, I'd guess it was less someone trying to pee on the A/C, and more someone that had to go didn't feel like walking inside.
posted by inigo2 at 6:31 AM on August 23, 2006

How do I clean this? Whether it's pee or not, the smell has got to go. I was thinking of pouring warm soapy water in through the vents on top. Any reason that wouldn't be safe? Any better ideas?

Get something designed to neutralize pee. I like Nature's Miracle, which works like magic, at least on cat pee. And human pee is much less obnoxious . You can get it in big bottles at Petco and you can shout "I am nature's greatest miracle!" like Homer Simpson while you pour it out.
posted by Mayor Curley at 6:32 AM on August 23, 2006

Hydrogen peroxide has been really helpful to me in getting rid of cat urine smells. It might help in your situation and it at least won't add any other odors.

I use the stronger hydrogen peroxide, it's actually sold as an environmentally safe liquid oxygenated bleach but on the ingredients it just says hydrogen peroxide.
posted by Melsky at 6:37 AM on August 23, 2006 [1 favorite]

I've had AC units that smelled like pee because they had standing water in them. Are you sure the water from condensation is draining properly?
posted by PlusDistance at 6:51 AM on August 23, 2006

not sure if this has any real relevance. but i used to work around large hvac units and every once and a while i would walk into a temperature controlled room and it would reek of urine. mind you this room was behind no less than three locked doors so it seems unlikely that anyone wandered in to take a piss. i never cared enough to look into what caused the problem, but dumping a bucket or two of water down the drain got rid of the smell.

i guess the point of my rambling story is that the smell may not have been caused by rude neighbors.
posted by phil at 6:56 AM on August 23, 2006

This may or may not be helpful, but wet or damp insulation [that pink/yellow fluffy stuff] smells VERY much like pee. Old pee will smell more like ammonia than pee. So, one thing you might want to do is checkto see if there is any moisture dripping on something insulated in your AC setup.
posted by jessamyn at 6:58 AM on August 23, 2006

The outside of the AC unit is designed to be waterproof, obviously, so a good hose down and use of products listed previously should help. If it was indeed pee from above then you might want to consider installing some sort of simple angled shield of either plastic or thin aluminum to prevent future occurences.
posted by JJ86 at 7:01 AM on August 23, 2006

Also....if you really think they are peeing on your A/C unit, could you have an awkward and polite talk with them? I mean, this is totally unacceptable!
posted by agregoli at 8:36 AM on August 23, 2006

Thanks for all the suggestions. There is a grill of some kind on the top face of the unit, but I have no idea where it leads. I like the idea of loading the room-side intake with some odor killer; that seems fairly risk free and would bring an airborne chemical in contact with the source of the problem.

How do I know if the condensation isn't draining properly? I remember when installing it that I was warned to make it level or else it wouldn't; it is level relative to the window. It worked last summer without issue, and this summer until now. It was off for about 24 hours before we turned on the fan and immediately noticed the smell.

If I ever know for sure that it was human caused, I will have that chat with the upstairs neighbors!
posted by Doctor Barnett at 9:20 AM on August 23, 2006

I doubt your neighbors are peeing on your unit. (oh how I thought Id live my whole life without ever typing that).

You're probably smelling burning freon which smells like ammonia, which smells like human pee. FWIW, burning refrigerant produces very toxic gases. I'd be very careful if I was you. Either your AC unit is dying or it might be a standing water/fungus issue.
posted by skallas at 9:45 AM on August 23, 2006

I've always found vinegar to be a great smell remover, though you certainly wouldn't think that when it's first applied, would you?
posted by phearlez at 11:29 AM on August 23, 2006

I also doubt it's actually pee. It's probably the freon or some other chemical used in the system. My parents have a similar problem with the AC in their car... every time it's turned on, the car starts to reek of piss-smell. Turn it off, the smell goes away... no one has peed on their car, it's done that since they purchased it. The dealer said that it's normal and would eventually the smell would "burn off", but they've had it for years now... the piss smell is just as strong.
posted by RoseovSharon at 12:32 PM on August 23, 2006

These guests, do they ever get drunk? Knowing some of my friends, the answer to #1 would be a foregone conclusion.
posted by Ogre Lawless at 3:33 PM on August 23, 2006