10,000 BTU Window A/C unit.
The cooling capacity of room air conditioners is measured in BTUs, or British Thermal Units, per hour. To figure the size unit you need, measure the space you're trying to cool and find it on this chart. To estimate square footage, multiply the length of the room by the width. (A room that's 10 feet by 20 feet, for example, has 200 square feet in it. The chart shows the recommended air conditioner for that sized space is rated at 6,000 BTUs.) To cool this area, look for this size air conditioner:
100 to 150 square feet 5,000 BTUs
150 to 250 square feet 6,000 BTUs
250 to 300 square feet 7,000 BTUs
300 to 350 square feet 8,000 BTUs
350 to 400 square feet 9,000 BTUs
400 to 450 square feet 10,000 BTUs
450 to 550 square feet 12,000 BTUs
550 to 700 square feet 14,000 BTUs
700 to 1,000 square feet 18,000 BTUs
1,000 to 1,400 square feet 24,000 BTUs