How long is too long for an AC cycle?

Under normal summer conditions and moderate weather, a standard air conditioning cycle should typically last between fifteen to twenty minutes before the system reaches the desired temperature and shuts off. However, during severe heat waves or exceptionally high humidity days, it is entirely normal for an AC unit to run continuously for much longer periods, sometimes operating for thirty to forty-five minutes or even non-stop to keep up with the heat load. An AC cycle is generally considered "too long" if the system runs continuously for hours on end without ever satisfying the thermostat setting, or if it runs indefinitely without shutting off. When an air conditioner runs endlessly, it usually points to a serious underlying mechanical or operational problem, such as critically low refrigerant levels caused by a leak, a heavily clogged air filter restricting airflow, dirty condenser coils preventing heat dissipation, leaky ductwork losing conditioned air, or a cooling unit that is physically undersized for the square footage of the home. Running an AC indefinitely wastes massive amounts of electricity and risks burning out the compressor motor.