When temperatures are high here in Austin, a properly sized AC system may run for very long periods of time in order to reach the desired indoor temperature (setpoint).
The AC system gradually reduces humidity and latent heat (heat that has built up in the walls, ceiling and surrounding surfaces) inside the home. It can take as long as an hour of runtime for every degree of temperature drop to achieve the desired setpoint inside your home. Once the desired temperature is reached, the runtime to maintain it is greatly reduced. However, if you feel your system is running far longer than normal or not achieving the desired temperature in a reasonable amount of time, it may be because of one (or more) of the following issues.