AC repair runs from $150 to $650 on average, based on the problem, labor, and the validity of the AC unit's warranty. Larger or more intricate air conditioner repairs might range from $650 to $2,500 or more if they are out of warranty. AC experts typically charge about $75 to $150 per hour for labor. A diagnostic service call might cost anywhere from $75 to $180, depending on where you live and the time of year. During the warmer months, HVAC technicians' time is in high demand, with some asking up to $200 per hour. So, always inquire before you book an appointment.