What is the tonnage of a heat pump with model number PH13nr042?

The model number PH13nr042 indicates that the heat pump has a cooling capacity of 42,000 BTU/h, which is equivalent to 3.5 tons. This is calculated by dividing the BTU capacity by 12,000 (the number of BTUs in one ton). Therefore, the tonnage of the PH13nr042 heat pump is 3.5 tons.