If your car's A/C takes 15 minutes to get cold, the system may be low on refrigerant, not performing correctly, and struggling to remove heat from the vehicle cabin. A properly working A/C should usually begin cooling within a few minutes, although a very hot interior can take longer. Delayed cooling can be caused by low refrigerant, a small leak, a weak compressor, a dirty condenser, a cooling fan problem, a clogged cabin air filter, or a blend door that is letting warm air mix in. Parking in direct sun can also make the first few minutes feel warmer. If the A/C eventually cools but takes too long, a technician should check pressures, vent temperature, airflow, and signs of leaks to identify the cause.