Which way to go with A/C evaporator leak?
I have a 12 1/2-year old split air conditioning system (outside condenser/compressor unit is Lennox 10ACB60-3P and evaporator unit in the attic is Lennox CH23-65-1; heating uses natural gas). I have had leaks for the past few years, but last year, it got so bad that the unit would not cool at all by the end of summer (in Phoenix, AZ). The leak has been isolated to the evaporator. The condenser/compressor unit is working fine. The gas furnace/air handler is also working fine.
Question: Which of the following should I choose?
1. Replace only the evaporator unit
2. Replace the evaporator and condenser/compressor units as a matched higher efficiency set
3. Replace the evaporator, condenser/compressor and the furnace/air handler.
Thanks.