How do you determine size for a window room air conditioner?

To determine the appropriate size for a window room air conditioner, measure the room's square footage by multiplying its length by its width. Then, refer to the manufacturer's BTU (British Thermal Unit) recommendations, which typically suggest around 20 BTU per square foot of living space. Consider additional factors such as ceiling height, sunlight exposure, number of occupants, and kitchen proximity, as these can influence the required BTU. It's essential to choose an air conditioner that matches or slightly exceeds the calculated BTU for optimal cooling efficiency.