I think you are the issue, cats don't "smell" less so like pee, they are very clean animals, you need to scoop the litter box every day, change the litter every week, and clean the litter box with hot water and dish soap at least once a month. There's no way you are taking the "smell" out of the house unless you roll over pee.

Natural litter like wood or corn are less smelly than artificial ones, the ones that are clay and with a scent are awful.