Deductions & credits

It depends what you mean by "Air Conditioned".

If it is a small unit, but energy efficient, it would be limited to $600.

Select "Central air conditioners" 

If it is a Heat Pump System (and judging form the cost I am inclined to think it is) and cost $6,000, the limit is $1,800.

Select "Heat pumps (electric or natural gas) 

(If I'm wrong, and it is just an air conditioner, the credit is limited to $600)