Can I install a new air conditioner on an old furnace or evaporator coil?
Using an old furnace with a new air conditioner is not a problem as long as the old furnace can deliver the required airflow. When it comes to the evaporator coil you can sometimes use the old one, but it’s not ideal. An air conditioner’s capacity and energy efficiency are certified only when matched with the proper evaporator coil and airflow. Since the minimum SEER rating for newly manufactured air conditioners increased from 10 to 13 on 1/23/06, the likelihood of having a problem using old evaporator coils has increased.
