Way too expensive.

 Try Home Depot and their various "roof vent" or "gable / attic" type fans for 1 THIRD or less the cost that do the same thing.


 A 12,000 BTU window A/C unit is actually *2 tons* not 1 ton.

 Evaporative cooling is a good option if you have a naturaly dry environment most of the year round (the "land of super low electric cost" in Central Washington is "semi-arid" near-desert with less than 1" of rain a month most months and EXCELLENT evap territory).