No, you don’t want your air conditioner to be too large. Air conditioners control the comfort level in your home or business by cooling air and removing humidity. An oversized air conditioner can cool faster but will use more energy and will not remove humidity adequately. In addition, your existing ductwork may not be able to support the airflow of a larger cooling system. An AC unit that is too big for your home or business will have short-run cycles. It will take a shorter time to cool the air, but the unit will shut off before enough air blows across the indoor coil where moisture condenses into water and drains from your cooling system. Too much moisture left in the air can lead to mold and mildew problems. These short-run cycles also mean your AC system starts and stops more often, which uses more energy and causes a lot of wear and tear. An air conditioner operates more efficiently during long-run cycles. The same holds true for heating systems. An oversized furnace can warm your house or business faster but it will use more fuel and cause greater temperature swings.