Why is Air Conditioner Capacity Is Measured in Tons

Air Conditioner Capacity Is Measured in Tons — Ever Wondered Why?

Why is air conditioner capacity Is measured in tons? One of the more confusing terms in the air conditioning industry is “ton.” When referring to an air conditioner, this word does not refer to the unit’s weight. Instead, it indicates the air conditioner’s capacity and ability to remove heat from your indoor environment.

Most sources say the term “ton” originated when buildings and rooms were cooled by ice. As the term evolved and became more common in the HVAC industry, it came to refer to how many British Thermal Units, or BTUs, of heat an air conditioning system can remove.

When calculating air conditioner tonnage, the basic measure is the amount of heat, in BTUs, that will melt a pound of ice back to liquid water. A pound of ice at 32 degrees requires 143 BTUs to melt it. Multiplying 143 BTUs by 2,000 pounds (a physical ton) results in 286,000 BTUs to melt a ton of ice.

The AC tonnage measurement was further refined to indicate how much heat would be required per hour over a 24-hour span to achieve the same effect. Dividing 286,000 BTUs by 24 gives the result of 11,917 BTUs per hour to melt a ton of ice in 24 hours.

This number is rounded up to 12,000. One ton of air conditioner capacity is the equivalent of 12,000 BTUs of heat removal per hour.

So what does the capacity an air conditioner mean to you? Knowing the capacity of an air conditioner helps when choosing a cooling system that is correctly sized for your home. A cooling load calculation performed in accordance with the Air Conditioning Contractors of America’s (ACCA) Manual J will tell you how much cooling is required for your indoor spaces, while a Manual S evaluation will tell you how to select the equipment with the capacity to provide the amount of cooling you need.

If you live in the Tampa Bay area, including the communities of Brandon, Plant City, Riverview, or Valrico, you can turn to Gulf Coast Air Systems for professional air conditioner services. Contact us today for more information on air conditioner capacity and what it means to your home comfort.