I have a 22yo 3 ton carrier (8 SEER) AC unit which is down and will cost $500 to repair and who knows how long it will last. I had someone come out and quote me an entire new HVAC system which includes

Trane 3ton 2 stage XL16i Seer 16 AFUE 80%

Trane Furnace 100,000 btu V/S

Matching Coil

Lew Line Set

New Condensing Unit Base

High Efficiency Media Air Cleaner

Programmable Thermostat

Humidifier

All Permits

Modify Existing Supply Plenum

Gas Piping

Installed $8400

Guess my biggest decision is fix my current AC for $500, replace my current AC unit only for $3000 or update the whole system. I have a 7yo gas furnace and blower that is to big for the house according to his manual J I live in Kansas City. Is the bang for the buck there in energy savings. I have storm windows and doors. Not sure what else you need to know just ask and I will try to get back to you.