1#feinet2001 1 N7 t3 W9 y4 q9 l) u( p' V9 ?
option 1: Two seperated furnances and seperated control& k P& t. O0 o( x ]+ X }$ ?; G4 B
(for big house > 3000 ft). v! M7 U4 u V( g" D5 {/ L
option 2: One furnance with Zone Control device & \5 ^3 t, O$ o (three zones or fours zone will be good) - total efficiency will be higher / q, n8 v$ H. }# z1 v0 N# G5 s, q. ]7 L; u. l' f O0 I
Total cost is not big difference.