The best course of action is to hire a licensed air conditioning installer who has a comprehensive, professionally designed AC Residential Load calculator. The term “size” of a central AC unit does not refer to the physical dimensions. Rather, AC unit size is a measure of its sufficiency to bring about cool air. It is measured in BTU, British Thermal Unit, per hour and in tons.
When sizing air conditioners, be careful not to make the error of getting one that is oversized. If the system you install is too big for the space, it will short cycle. In other words, the compressor will not run long enough to dehumidify the area and will limit your comfort. In addition, it will cycle on and off more often, increasing operating costs and reducing the system life. Appropriate air conditioner sizing is essential to optimize performance.
24,000 Btu’s/12,000 Btu’s per ton = 2 tons
Use the following conversion information to determine your existing system size (use the system model number NOT the serial number)
- 18 = 1.5 tons
- 24 = 2 tons
- 30 = 2.5 tons
- 36 = 3 tons
- 42 = 3.5 tons
- 48 = 4 tons
- 60 = 5 tons