I just got 4 quotes from 3 reliable local contractors (NJ), for a 2 1/2 ton , 13 seer unit. My problem is my duct work was not done right on the original system and has to be be ripped out and replaced. All contractors were of the same oipnion without being informed.
Anyway, the quotes ranged from $10,700, $9800, and $8650. I found a local A/C Technician that works on our office building system and does side jobs. He quoted me $5300, I paid for the materials direct to the supply house $2300 for an Arcoaire System, 10 year warranty, $1400 for the duct work and $1600 for his labor. Saved myself over 3K and he is halfway done, two Saturdays to do the whole job. Nothing against the contractors but they have alot of overhead to cover and I kinda cut that piece out of the equation. If you can find a local tradesman that is reliable and good, you can save a bundle. if its a straight replacement, Id say your looking around 3500- 4K for a good deal and around 5-6k on the high end.