
What Is the 20-Degree Rule for Air Conditioning?
If your air conditioner is running but your home still feels warm, you may have heard about the “20-degree rule.” It usually refers to the temperature drop between the air entering your AC and the cooled air leaving it. A drop of roughly 15–20°F is a common starting point for checking cooling performance, but it is not a pass-or-fail test. It also does not mean your home can only be cooled to 20°F below the outdoor temperature. Here is how to understand the difference and decide when your AC needs attention. What the AC temperature split tells you The temperature


