The size of an air conditioner you need for your space is a critical factor that impacts the efficiency and comfort of your environment and your energy bills. To find the right size, you must consider several factors beyond just the square footage of the space. These include the height of your ceilings (since higher ceilings mean more volume to cool), the quality of your insulation (poor insulation requires more cooling power), the size and orientation of your windows (large, south-facing windows can increase heat gain), and even the number of occupants typically in the space (more people generate more heat). Professionals use the Manual J calculation, a comprehensive method that considers all these factors, to recommend the correct size. An oversized air conditioner can lead to excessive humidity and uneven cooling, while an undersized unit will need help to cool the space, leading to inefficiency and wear over time.