This is the furnace system of the new house. For the most part, the furnace has one big pipe that goes throughout the first floor. However, there is an additional pipe that services just the bonus room, which is essentially sandwiched between rafters in what would normally be the attic. This is a new concept for us as well. In general, the midwest doesn’t have bonus rooms. Instead, people finish their basements for extra play space for the kids and extra storage space for those seldomly used items.