Why Is Your Air Conditioner’s Cooling Capacity Measured in Tons?
A ton is the standard measurement unit for the cooling capacity of air conditioners. But, what do tons have to do with air conditioning? It’s not reflective of their weight, as a one-ton A/C unit doesn’t weigh one ton, or 2000 pounds. Instead, the answer goes back centuries.
Why Is the A/C Measured in Tons?
Before modern air conditioners were invented, large blocks of ice were harvested in the winter and used for cooling, and kept frozen for the summer. Customers would buy these blocks from ice companies for use in cooling boxes and in primitive ice-based cooling units.
When modern air conditioners were being developed, manufacturers needed a way to demonstrate to consumers how much capacity a unit had. The easiest way was to compare it to the cooling ability of ice. So, a one-ton A/C unit equals the cooling capacity of one ton of ice.
Later, the tons used in measure A/C capacity were standardized to equal 12,000 BTU per hour of cooling ability.
Determining Your Home’s Cooling Needs
In years past, A/C contractors would use various rules of thumb for sizing the cooling equipment for a particular home. One well-used rule of thumb was estimating one ton of A/C capacity for every 400 square feet of space to be cooled, and then throwing an extra ton in for good measure.
The problem with using rules of thumb is that they often result in having A/C systems that are significantly oversized. This problem has only gotten worse over the years as homes have gotten more efficient, resulting in lower cooling needs.
Today, a professional A/C contractor will use Manual J to calculate the cooling capacity your new equipment needs.
For more information on cooling your home, check out the air conditioning solutions available from Mike Merritt Heating & Air Conditioning, or call 904-240-4038.