I have an 18-yr old 2.50 ton 10 Seer R22 split system with a 3 ton evap coil and a 75,000 BTU gas furnace blower-air handler in the attic. The new 3 ton 13 Seer condensor and new evap coil would be R22 so I am not trying to mix with new R410? refrigerant.

My question is: Do I really need to change the line set out or can I use the existing lineset? I know there is different line set sizing for the new systems. The line set is about 60 feet long and most is in the attic but some does travel down behind the brick outside wall. The new lineset would have to be run on the outside of the house. Thanks in advance for your help.