1#feinet2001 $ N( d7 I* \& |% [4 c, h; a4 D/ X, W7 z. S P! A' ]" ~* G6 ^
option 1: Two seperated furnances and seperated control 6 F5 x8 P3 m& H6 v Q (for big house > 3000 ft)! r& ]7 i6 p5 W* c7 {; `* w
option 2: One furnance with Zone Control device ! B1 [4 s; e: q2 N' P! L) o
(three zones or fours zone will be good) - total efficiency will be higher 2 d) `# ~9 ]( e) U( R5 \' v/ G- y
Total cost is not big difference.