1#feinet2001( k+ i) R2 u! v# y+ j/ L% s
; V3 P/ O8 {6 {& i: j* C! k
option 1: Two seperated furnances and seperated control ; u' x* D9 N; z (for big house > 3000 ft)* B$ F& w4 N/ s4 Y' T9 R; P
option 2: One furnance with Zone Control device 9 R3 c# f [+ V+ u4 W* q/ z2 ^
(three zones or fours zone will be good) - total efficiency will be higher$ G2 g: b3 Q% R+ R
) A# l2 f( T. e8 E1 G, h# C
Total cost is not big difference.