577EUp to 16 SEER2Up to 11.5 HSPF2Up to 81 AFUE 607EUp to 15.5 SEER2Up to 7.5 HSPF2 677EUp to 15.5 SEER2Up to 7.5 HSPF2Up to 81 AFUE 707EUp to 16 SEER2 577CUp to 13.4 SEER2Up to 81 AFUE 607CUp to 13.4 SEER2Up to 6.7 HSPF2 677CUp to 13.4 SEER2Up to 6.7 HSPF2Up to 81 AFUE 707CUp to 13.4 SEER2 PA4ZUp to 13.4 SEER2 PH4ZUp to 13.4 SEER2Up to 6.7 HSPF2