& s V5 c* B$ F J9 x$ ?; U0 eoption 1: Two seperated furnances and seperated control 1 A' }0 e/ |! [) t) ^ (for big house > 3000 ft)+ ^& w* ?+ @# D0 a4 X: n8 F
option 2: One furnance with Zone Control device % U- T4 r3 Z: O- @1 w9 W (three zones or fours zone will be good) - total efficiency will be higher$ O5 x- e$ }, E8 B2 ~
, I# E9 N! D3 g
Total cost is not big difference.