Cat pee/urine smell removal

[Diane Dib]

I am looking at a property that smells of cat pee. I've seen it a couple of times, and it was obviously worse when the weather was warmer and it's barely warm at all right now. The house is still furnished and has one large throw rug. I think once the carpet and upholstered items are out, it will smell better but I don't think it will be smell-free.

I've read a number of posts here on this topic and see that some of you look for these places since others tend to run from them. I like that approach! But I still need to get rid of the smell. 

Most posters say to use oil based Kilz, but are you also using some sort of enzyme odor remover prior to this? I have had sick cats in the past and am familiar with black lights to find it, but the best results I had were when I re-shellacked my floors (which is what was originally on my floors anyway). That said, my house smelled like roses compared to this one so I know I'm dealing with a different beast!

Are there companies that are good at eradicating odors or am I better off doing it on my own. Any suggestions are appreciated as I need to factor this into my budget for purchase.