" [; J: f8 j0 `5 ioption 1: Two seperated furnances and seperated control , V5 q: |# ~/ G6 o2 |3 d* O (for big house > 3000 ft) 4 l; U, @/ Q o2 \( ]option 2: One furnance with Zone Control device % | q9 O1 p: A (three zones or fours zone will be good) - total efficiency will be higher / e, O6 u/ H: j- p1 a4 Q# B$ f& K2 t3 z1 P% P3 `% ?8 v4 @! T7 G
Total cost is not big difference.