A 12.5 ton package unit is a type of air conditioning system that is typically used in commercial and industrial buildings. It is a self-contained unit that combines the functions of an air conditioner, furnace, and air handler into one unit. The unit is usually installed on the roof of the building and is connected to the ductwork system. It is designed to provide efficient cooling and heating for large areas. The unit is typically rated for 12.5 tons of cooling capacity, which is equivalent to approximately 42,000 BTUs per hour. This type of system is ideal for large commercial buildings, such as office buildings, warehouses, and factories, where a large amount of cooling and heating is needed. It is also energy efficient, as it can be used to cool or heat a large area without having to use multiple units.