What size air conditioner do I need?
Your air conditioner should have about 20 BTU per square foot of living space, according to Consumer Reports. However, you should also account for other factors in the room.
If it’s a very shady space, you can take off 10% of the square footage BTU calculation. If it’s sunny, add 10%. For rooms normally occupied by two or more people, you should add 600 BTU per additional person. Finally, if the room is a kitchen, add 4,000 BTU to your calculated square footage total.
Talk to an air conditioning company or HVAC professional to find out what size you should get.