A/C units are rated in 'tons' and a year or so ago I went through the exercise of converting this to rational units. I needn't have bothered, really, because the electrical circuit that runs the unit gives the game away. A typical domestic unit uses 6Kw. A larger "ranch style" house may need two or more of these.
Solar panels are quite good at offsetting most of the power drawn by A/C. Our roof knocks out up to 4.5Kw; its not a particularly large installation but it does have the advantage that its on all day, every day. (Panels also act as a roof shade.) If you've got a large installation, say over a parking lot or commercial building, you'd be amazed at the amount of power panels can produce -- one typical sized rank will produce over 40Kw (while keeping your car cool).
As for that 'ton' thing -- this measure of cooling is the amount of cooling you get from a ton of ice over a 24 hour period. Domestic A/C units are 3-5 tons.
Biting the hand that feeds IT
