One of the bed rooms on the first floor is colder than other bed rooms on the same floor. This bed room is situated above the garage and has a separate HVAC duct work (zoned). It remains unusually cold and the heater keeps running in order to keep it warm. The room has hard wood floors and the floor is at a lower level than the rest of the first floor. I would like to use this room as an office and what can I insulate the room better?