What was your desired temperature in summer? The heat pump is sized for cooling not heating. The auxilary heat should have kept you warm when it was real cold outside.
btw... 2.5 ton is 30,000 btuh's nominal
Theres a good chance it is not performing due to a charge, airflow, or distribution issue.
[Edited by docholiday on 03-08-2005 at 08:43 PM]