One big complaint that many cat owners have or people that want cats, but are putting it off is that they're afraid they're going to be smelly. The truth is, is that most cats really don't smell very much at all. I mean, they do a pretty good job bathing. However, if you don't monitor that litter box, you are going to have a smelly house or at least a smelly room and your cat might veto the box entirely if it's dirty and go to the bathroom somewhere else in the house.
So, if you're worried about cat odor, think first about the litter box itself. Make sure that you're cleaning the box at least twice a day and scooping out any solids and disposing of them outside of your home. In addition, make sure to replace the entire litter box litter itself at least every week. If you wait longer than that, you're definitely going to have smellier litter present in your home.
Now, some puppy litter say that you can leave them in for up to a month and that's fine, but just keep in mind that many people with smelly litter boxes actually forget when they last replaced all of their litter. So, if you're going to go an entire month, make sure to mark it on the calendar and replace it judiciously. Other things to keep in mind are keeping the box itself clean not just the litter.
So, when you change the litter every time you do so, make sure that you wash the box out. Do this with just the mild soap and some really hot water. If you can, set it out in the sun to dry so that you can get a little bit more antibacterial effect. Do keep in mind though it's important not to use harsh chemicals in your litter box because the cat has to go to the bathroom in there and they have a really great sense of smell. If it smells funny, they might not be comfortable using it.
If you have cat odors that are in your fabrics or in your carpet, research shows that the most likely thing to help that is actually Febreze [SP] with cleanse air. So, as long as you feel comfortable having that product in your environment I certainly recommend you get some and spray the areas where your cat hangs out. Otherwise, I think if you keep your box clean, you'll find that litter box smell and cat smell overall just really aren't a problem for you. That's how you keep your house cat odor free.