Never had a problem and today I got home and when I walked in it smelled really musty almost like cat urine. I went and checked Yoshi *she is in a crate while I'm gone* and no accidents and she nor the pillow in there smell like it. I can't smell it upstairs just downstairs *according to my dad they are separate a/c units* The air filters were just changed it isn't urine and I only smell it coming from the floor vents. Has anyone ever dealt with this? How did you get rid of the smell. It's not horrible you don't notice it after being here a minute and I'm allergic to almost everything and I don't even have a beginning of a headache and I've been here all night. Just want to get it taken care of before it's is much of an issue. I'm going to just try to air out the downstairs this weekend if it doesn't rain.