i would say smallest you should go is a 8 foot long 2 foot deep 18 high .As for the type,there are many diffrent types of enclosures on the market that you can chose from .Or you can build your own as well.Not knowing how much space you have is kinda hard to say what is suitable. What you can do is move all your furniture to one side of the room and build a enclosure the size of the space left