Audited overall ratings (18 customer reviews)

SCHOOL" CO2 traffic light

Possible applications

  • Surveillance of seminar rooms, classrooms, lecture halls, kindergartens
  • for all rooms where people spend long periods of time on a regular basis
  • Reliable reminder for regular draught ventilation
  • Standard colour RAL 6024 "Traffic green
  • Optionally available in white (RAL 9016) and grey (RAL 7032)


incl. VAT

plus shipping costs

Total: 251,34 

Delivery time: 2-3 workdays


Performance features

  • Easy installation without electrician, wall mounting
  • optical display, from 1000 ppm yellow, from 2000 ppm red
  • Adapted electronics for trouble-free teaching
  • Detection of Carbon dioxide (CO2) from used air
  • internal infrared sensor 3000 ppm (+/- 0.01%vol.)
  • automatic shutdown of the LEDs in the dark
  • Standard color green (RAL 6024)
  • optionally available in the colors white (RAL 9016) and gray (RAL 7032)

The optical warning device measures elevated CO2 levels in indoor spaces where many people regularly spend time - such as classrooms, gymnasiums, auditoriums and lecture halls, kindergartens and common rooms.

According to EU standard EN 13779, as little as 1400 ppm CO2 in indoor air is considered "very bad air"; the maximum workplace concentration MAK in Germany is 5000 ppm.

The "SCHOOL" CO2 traffic light with its yellow light reminds already from 1000 ppm according to a recommendation of the RKI for extensive shock ventilation of the room.

FAQ about CO2 traffic lights
  • - How much electricity does the CO2 traffic light actually consume?

    Due to the automatic dimming of the LED lights of our traffic lights at night, the actual power consumption is extremely low and thus also helps to save energy:

    0.03 kWh in 24 hours*

    (Important: the traffic light should not be disconnected from the power supply at night because the automatic self-calibration is designed for 7 days of continuous operation in order to determine better, more realistic standard values!)

    *current measurement as of 08.11.2022

  • - On which side and at what height should the traffic light be mounted?

    The traffic light is not mounted directly next to the windows on a wall. The height of the traffic light should be high enough to be visible from as many places as possible and at most so that the touch field for resetting the acoustic signal can still be touched comfortably with the hand.

  • - How many square meters does a traffic light cover?

    CO2 from breathing air is distributed quite homogeneously in the room. In classrooms, one traffic light is sufficient, a standard gymnasium should be equipped with 2 traffic lights and a Pax400 auditorium perhaps with 3 or 4 traffic lights. This also depends on the room geometry and cannot be expressed in square metres.

  • - How long does it take for the device to be ready for operation after it has been switched on?

    [embedyt][/embedyt]In less than 90 seconds the first meaningful evaluation with immediately displayed result takes place.

  • - Does the device stay on continuously for 24h or is it to be switched on every time the room is used?


    The traffic light is suitable for both possibilities; if it is only switched on when the room is in use, one can assume a longer service life.

  • - Does a self-calibration take place?

    To ensure consistent correct Co2 measurement results, make sure that the Co2 traffic light is switched on every 7 days (from year of manufacture 2021), or every 24 hours (before year of manufacture 2021) is exposed to fresh air for at least 30 minutes. Simply ventilating the room in which the measuring device is installed is sufficient for this. This leads to a constant self-calibration, thus to the full and accurate functioning of the device.

  • - The instructions say: "Inspection after 5 years". How does that work?

    Basically, you can check the sensor yourself. Simply blow on it calmly for about one minute and observe the colour changes on the traffic light. You can also send us the traffic light for a free factory inspection, during which we may readjust the sensor. If we need to replace the sensor, you will receive a discounted replacement offer, just as with all other gas detectors from our company. Regular or daily draught-ventilation also helps the traffic light to a higher and longer reliability.

Operating note


  • Please do not unplug your traffic light overnight! The auto-calibration is set to a weekly rhythm that has been specially adapted to everyday school life. The nightly rest periods and the daily - or at least weekly - shock ventilation provide the necessary average measured values for the calibration to the theoretical zero point.
  • During longer breaks in operation - e.g. during school vacations - the CO2 traffic light "school" can be taken off the grid.
  • Particularly energy-saving due to the integrated light sensor, which dims the LEDs after 10 minutes.

Technical data

Operating voltage: 12 V DC from enclosed plug-in power supply unit
Supply cable traffic light / power supply unit: approx. 80 cm / approx. 150 cm
Protection class: IP 20 (IP54 possible at extra charge)
Sensor type: NDIR Infrared, internal
Trigger concentrations: approx. 1000 ppm yellow / 2000 ppm red
highest trigger concentration CO2: approx. 2000 ppm
Sensor measuring range: 400 - 3000 / 5000 ppm (+/- 100 ppm / 5%)
Functional area sensor: +5°C / +45°C
Humidity (ambient): 5-90 % RH (non-condensing)
Illuminant: Long-life LEDs with automatic night switch-off
Dimensions (HxDxD): 303 x 55 x 80 mm

Scope of delivery

CO2 traffic light with 0.8 m supply line and wall mounting set
Plug-in power supply unit with 1.5 m supply cable and hollow plug
Operating instructions and info card


Instructions for use

CO2 traffic light "SCHOOL" - item no.: 400250

Product data sheet

CO2 traffic light "SCHOOL" - item no.: 400250

CE Declaration

400250 CO2 traffic light "School

Operating note

Operating note CO2 traffic lights

Product video

18 reviews for CO2 traffic light "SCHOOL

Based on 18 reviews
5 stars
4 stars
3 stars
2 stars
1 star
  1. Easy installation. does exactly what it should

    (0) (0)
  2. Good product, easy to assemble

    (0) (0)
  3. The traffic light makes a solid impression, mounting material is included.

    (0) (0)
  4. Visually very appealing, I have to test the functionality first, I've only had it for 2 days( weekend).

    (0) (0)
  5. (0) (0)

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