The size of the air conditioner equipment does not refer to the physical dimensions of the air conditioning unit, instead, it refers to its cooling capacity measured in British Thermal Units (BTUs). Whether you plan to install a central air machine or a window air conditioning equipment, you will achieve optimum efficiency… Therefore, lower utility costs if you choose your air conditioning equipment based on the size of your property or the part your machine must cool. To choose what air conditioner size is necessary for your property, first, you will need to calculate the size of your property’s areas that the air conditioner equipment will serve in square feet. To calculate the size, multiply the width times the length of the part to be cooled. The total results are then multiplied by 25 BTU, which is a practical number. This size will allow sufficient cooling under any climatic condition, be it a rainy, hot, sunny, moist, or humid day… For example, given a room that is 12 feet wide by 15 feet long, you will multiply the length by the width 12×15 to get 180 Square feet. The 180 square feet will then be multiplied by the 25 BTU per square foot to get you the lowest BTU air conditioning equipment you should install. This means 180 × 25 = 4,500 BTU cooling capacity is absolutely needed for your space. While smaller BTU equipment will run continuously to keep up with your temperature requirements, having too many will cool too speedily however won’t remove moisture from the air in your property.