it's going to take more then one to take care of a house that big.
You can check into the ones that are installed directly into your central air unit...if you have central air of course.
other then that, just depends on what you want really...in our place...we have a big one..that still needs to be filled every 36 hours or so..and a small one in our bedroom that keeps getting shut off, because SOMEone can't sleep with the fan noise it makes. LOL! right now, their both in need of new filters because our water is so hard, it kills them off pretty quickly...especially when their not refilled for over a week! LOL!
