Our A/C hasn't been up to snuff, and we had two separate companies look at it and say that it's just too old and it needs to be replaced. One of the companies gave us a quote for $4950 for a 100,000 BTU 80% efficiency furnace and a 3 ton, 13 seer A/C (both Ruud). That seems like a really good deal. He did add extra quotes for upgrades. They have really good reviews on Google (Hill Heating & Air). We also got a quote from Genuine Comfort for about $5000 for what looks like just an A/C replacement.