1#feinet20019 }+ a! z' F3 [9 W! x! E
$ L$ v( a" e7 ]) x! x6 z* K/ j- t
option 1: Two seperated furnances and seperated control 3 L, g7 \# v" w. F) E* x! s! ? (for big house > 3000 ft) 0 w! `" k+ _8 {! Z7 [option 2: One furnance with Zone Control device / q5 t9 ?" n9 o% ~ (three zones or fours zone will be good) - total efficiency will be higher) V, B! \2 m' A7 G* R- F; i3 T# v
+ r7 {0 n& ~- O5 E8 |Total cost is not big difference.