- F# k1 f& p; a$ {1 s$ r: ^option 1: Two seperated furnances and seperated control N9 ~: E" k+ V$ g9 j0 ^ (for big house > 3000 ft)- C, b4 \2 i$ x" F! T5 c
option 2: One furnance with Zone Control device . ~% S0 T" f9 [) w7 h! \1 E (three zones or fours zone will be good) - total efficiency will be higher 1 F) N* ^5 u* b. k9 W( V# l l) ~2 f
Total cost is not big difference.