In North America, no formal standard for testing or publishing cooling capacity exists, so most manufacturers use the maximum temperatures at which the air conditioner is designed to operate (internal and external) as reference points. The maximum operating temperatures can differ between air conditioner models as well as manufacturers. A typical maximum operating temperature is 131°F. If indicated, the rating temperatures could be shown as L131/L131 or Ti 95/Ta 95 or 95°F/95°F. Traditionally, the first number stands for the internal temperature.

In Europe, a standard called DIN 3168/EN 814 part 500 (European standard for enclosure climate control) is used. This standard levels the playing field and provides a more realistic measure of performance by requiring all manufacturers to use the same temperature conditions to determine cooling capacity - allowing users to make true one-to-one comparisons.