The microprocessor-controlled CO2 measuring device is used to record the CO2 content of the air in the range from 0 to 5000 ppm and the room air temperature. Measurement signals are shwon by a digital display. The CO2 content is determined by means of an optical sensor, non dispersive infrared technology. By using the sensor according to the dual principle, interferences of the measurement by pollution and aging can be excluded as far as possible, so that a long function time of the device is ensured. Under normal operating conditions you do not need to calibrate the measuring device. By reason of the large display, the use oft he measuring device is particularly recommended in large rooms or areas.