TWO air-conditioning systems are available on the C-class, the Thermatic climate control system with automatic fan control and air distribution, and the luxury Thermotronic climate system standard on Elegance and Avantgarde models that adds a sun and pollutant sensor, an activated charcoal filter, a more elaborate display for temperature and fan speed, and rear ventilation outlets. Compared to its single-sensor predecessor, the new units have two sensors to measure the interior temperature and supply the system with more precise data to respond to temperature fluctuations.