Cat urine smell but no cat

It could be from a previous occupant of your home that may be leftover (if you are not the first occupant of the home). The best way to remove the smell of the room if it is carpeted is to pull up the carpet and pad and paint the floor underneath, if it is concrete slab with kilz, let the floor dry for at least 48 hours, install a new pad under the carpet you can purchase inexpensively from your local home improvement store, install the pad and previous carpet (after cleaning carpet with pet odor remover). Then you should have no odor problems again. I was a apartment complex manager for over 20 years and have seen this work hundreds of times.

Try white vinegar

Change or paint the pieces of wood under the AC.

A cat might have sprayed your pieces of wood under the AC if you had them outside. Toss them and replace. You might want to paint them first, just in case.

I am not sure the spraying under the a/c unit would work if the problem is with only one room smelling like cat urine. If the majority of the house smells bad, then that may work, however this problems seems to be located to one room. One way to test all these theories is to turn off the a/c on at hot day, leave your house for about 4 hours, then you can return with a clear nose to be able to locate the exact point of the location of the smell. As an additional note a cat could have urinated (as mentioned) on your baseboards also and if that is case, painting them with kilz will remove the smell also.

I have an old rug, but a brand new house, no pets. After we moved in about 6 months later I started smelling cat pee down in our heated basement. I FINALLY after weeks of searching, discovered the uderlayment , ( rubbery padding) had broken down and started to smell like cat pee! Maybe you have the same such issue?

Our car smelled like that and it was a leaking air conditioner that caused mold. The other thing is an air conditioner should really be tilted out and down so the water drains outside. Another possibility is that the odor is coming from outside and the air conditioner is bringing the smell in. Maybe there really is a neighborhood cat urinating outside the window, or some evergreens smell like urine. See if you smell it outside.

A mail unneutered cat must have sprayed your air conditioner unit. Try

zero odor pet. You can order it through Amazon. It may take a few sprays for several days, but it is effective.

there has got to be another solution .. if it's a house occupied for 15 years or better and no cat, but also a problem with shower pipes to where they are leaking .. is there any way possible the odor is being misconstrued as cat pee rather than mold or musty wood under the upstair main bathroom floor ?

Get a "black light" bulb and explore the room in dim to dark light--if it is cat urine, the black light will "see" it

Could a cat have sprayed on the outside of the house on the ac unit and it is being pulled in via that route? Use a black light to find the urine source. We did that and was very surprised to see how well that works.

Here's a post that might help https://www.bobvila.com/slideshow/if-your-home-smells-funny-check-these-8-problem-areas-53144#:~:text=Even%20people%20without%20feline%20friends,be%20remediated%20by%20a%20professional.