text: i have a 24 square meter room,  is a 12000 btu air conditioner efficient  for it ? how do you decide the best btu for a room ? the first guideline that i found was:  7500 btu:     150 square feet 9000 btu:     200 square feet 10000 btu:   250 square feet 12000 btu:   350 square feet 13000 btu:   400 square feet  so, 12000 btu is probably fine.