I upgraded last year, got a Armstrong 3ton 12 seer.

I paid juts over $600 for the unit, and $200 for installation.

My HVAC guy told me that that the same unit today is $1200, DAMN, doubled in price in a year.

I work for a major HVAC/R wholesaler and sell a competive brand of A/C units. The 10 & 12 SEER units are still the same price on my end as they were. It's the new 13 and 14 SEER units that have R410A as a refrigerant are more  expensive to retrofit since the evaporator has to be changed out as well, due to the much higher system pressures. They are physically much larger too (25-30%) for the added efficiencies, which means it has more steel, aluminum, copper etc..  As of 2006 no more units can be produced using R22 so they are doing all they can to get people moving in the newer higher SEER direction. Some dealers and suppliers are artificially raising the lower SEER unit pricing to make it less of a gap to move up to the newer High Efficency models the Manufacturers are pushing down to the Wholesalers.

just an FYI moment