My 23 year old central AC decided to pursue a career as a noisy lawn ornament rather than cooling my house last month. I knew this was going to be expensive so I decided to employ the same method I use when buying a car. Get 2 dealers to fight over me. Long story short, $4,552.00 original estimate for a generic 3 ton 14 seer unit down to, $3,499.00 for a top line Carrier 3 ton 16 seer. Yippy, I win!