Automatic air-conditioning employs a range of sensors to ensure constant thermal comfort, whether the driver is alone or the whole family is in the car, travelling in sweltering weather to get to the seaside or in the freezing winter to get to the ski slopes. Simply press the Auto button and set the temperature, ideally around 22 °C. Even if the AC sign is lit up, this does not mean that the air-conditioning is delivering all it is capable of. Modern systems regulate the operation of the compressor to reflect current conditions. In doing so, they draw on a solar sensor that monitors not only the intensity, but also the direction, of the sun’s rays.