For those who don't have central air, a window or portable ... only comes in two sizes (6,000 and 8,300 BTUs), it's best for smaller spaces. Read our full Windmill air conditioner review.

Large rooms require an air conditioner with enough Btu to keep you cool. The Frigidaire 14,000 BTU Inverter Window Room Air Conditioner (model FHWW145WE1) can comfortably handle lofty and open spaces.