What does the term "tonnage" refer to in HVAC?

The term "tonnage" in HVAC specifically refers to the cooling capacity of an air conditioning unit. This measurement derives from the amount of heat that one ton of ice can remove over a 24-hour period, which is equivalent to 12,000 British Thermal Units (BTUs) per hour. This standard helps to quantify how much heat an air conditioning system can effectively remove, making it a critical factor for ensuring that a cooling system is appropriately sized for the space it serves.

Understanding tonnage is essential for systems design and selection; it allows HVAC professionals to determine how much cooling a specific area requires based on factors such as square footage, insulation, and occupancy. Proper tonnage selection helps to ensure energy efficiency and comfort, preventing systems from being oversized or undersized, which can lead to operational inefficiencies and increased costs.