The reference CO2 sensor

For over 10 years, Class’Air sensors have been used to monitor indoor air quality. Three-colored LEDs provide a warning in the event of high CO2 concentrations, and raise awareness of good ventilation practices.

20,000 deaths

are caused by indoor air pollution every year.

54% of French people

are concerned about air quality in nurseries and schools.

10 to 20 times

Indoor air is 10 to 20 times more polluted than outdoor air.

19 billion euros

is the annual cost of indoor air pollution.

Indoor Air Quality in France :

Legislation concerning Indoor Air Quality in France’s public buildings will change in December 2022. Already mandatory in certain establishments such as schools, the decree extends the obligation to monitor indoor air quality to other ERP. The conditions for air quality measurements now involve three types of assessment:


  • The annual assessment includes direct-reading measurement of CO2 concentration, using it as a tracer of indoor air renewal.
  • Every 4 years, the self-diagnosis covers the identification of sources of pollutants, ventilation and aeration maintenance, and pollution generated by work and cleaning activities.
  • At every key stage in the life of the building.

For improved indoor air quality

Simple indoor air quality measurement

Class’Air measures CO2 levels in a room. 3 tricolour LEDs indicate CO2 levels according to configurable thresholds.

Market benchmark

For over 10 years, Class’Air has been referenced in the Ministry’s IAQ guide and ADEME’s Ecolair guide, and developed in collaboration with the CSTB.

Environmental impact

Our sensors are eco-designed, repairable and have minimal environmental impact. Our batteries are rechargeable.

NDIR CO2 sensor

Class’Air is equipped with an NDIR probe, the reference technology for CO2 measurement. Our probe is guaranteed for 5 years!

Quick and easy to use

Class’Air CO2 sensors are quick and easy to install. In no time at all, measurement campaigns are launched, and the results are visible in real time on the screen.

French solution

Our Class’Air products, like all our solutions, have been designed and manufactured in France by our teams based in the Pyrénées-Orientales region since 1989.

Class’Air, a range of three sensors


The Pedagogic sensor provides a simple, intuitive display of CO2 levels in real time. Visual and audible alerts encourage ventilation.


In addition to the functions of the Pedagogic sensor, the Class’Air CO2 sensor recorder facilitates measurement and annual campaigns.


The Class’Air Connected CO2 sensor lets you view data in graphical form and generate alerts via the new web platform.


The Class’Air case, for testing establishments and local authorities, contains 5 to 10 Class’Air sensors for easy campaign implementation.

A solution for everyone


For almost 10 years, Class’Air has been supporting schools in their campaigns to improve Indoor Air Quality. It is referenced in the Ministry’s IAQ guide and ADEME’s Ecolaire guide.


Seniors spend most of their day indoors. To avoid the harmful effects of too high a concentration of CO2, it is essential to control Indoor Air Quality.


Indoor air breathed in open-plan offices is 10 to 20 times more polluted than outdoor air. Fitting CO2 sensors and educating employees about ventilation could be a solution!


Designed for laboratories, the Class’Air CO2 sensor meets the most demanding requirements for ensuring healthy air in strict environments.


The legislation also applies to many other ERP facilities, such as social and medico-social structures, as well as prisons for minors.

They trust us

Deploying Class’Air CO2 sensors in 5 stages :



Step 1
Step 2
Step 3
Step 4
Step 5

Assess your needs

First of all, you need to assess your air quality measurement and control requirements, and determine the number of sensors you'll need.

Choose your sensor type

Different types of sensor meet different needs. Choose the sensor that's right for you! Our sensors are available in 3 versions: Educational, Recorder and LoRa Connected, and can be customized.

Install the sensor in the room to be evaluated

Sensor installation is very quick: simply place the sensor in the room you wish to control, away from any openings (windows and doors), and you're done!

Set alerts

On our web platform, you can choose your visual and audible alert thresholds according to your needs. These settings can be changed at any time!

Train users

The Class'Air CO2 sensor helps raise public awareness of ventilation. It is still necessary to inform them of alerts so that they can recognize the signals and react accordingly.

Technical data :

Dimensions: 93.7x103x36.6mm
Weight: 175g
Autonomy: 12 months
High-precision NDIR probe (50 ppm + 3% of measured value)
All our sensors are supplied with a calibration certificate.

Parameters measured :

  • Carbon dioxide CO2: 0 to 5,000 ppm
  • Temperature: -10 to +50 °C
  • Humidity: 0 to 100% RH
  • Pressure: 300 to 1,100 hPa
  • Configurable measurement period: 1 point averaged over 10 minutes by default.

Visual and audible indicators :

  • 3 LEDs (red, orange, green) with adjustable thresholds
  • A display showing temperature, CO2, pressure and hygrometry
  • A configurable audible signal when the high threshold is reached
  • LEDs and beeper can be switched on or off

Any other questions? Contact our experts!

Our teams are available by telephone on +33 4 68 68 39 68 or by email at, Monday to Friday, 9am to 6pm.

Frequently asked questions


How many CO2 sensors do I need to equip my premises?

In general, one sensor per occupied room is required for optimum control of your facility's indoor air containment. However, depending on the size of your rooms, the number of sensors may vary. In fact, we recommend one collector for every 50m2 of floor space. If this surface area is exceeded, we recommend the use of one or more additional collectors.

For large areas, we can advise you on how to optimize the number of sensors required, while guaranteeing measurement accuracy.


How to install CO2 sensors?

Class' Air CO2 collectors are very easy to install. Here are our recommendations for the best way to arrange them:

We recommend mounting the sensor bracket on the wall, at a height of between 1m20 and 1m50. The sensor should be located in the most confined area of the room, away from openings (doors and windows) and air flows.
The sensor can be attached to its support, or can be relocated until all your rooms can be equipped.
Class'Air CO2 sensors are factory-set and preloaded. No special handling is required for installation.


How are Class'Air CO2 sensors powered?

All Class' Air collectors are self-contained and require no permanent connection to the building's electrical network.

Two types of feed are possible:

-On rechargeable battery with one year autonomy (with factory settings) on our educational sensors and recorders;

Battery-powered, with 3-year autonomy on our connected model.


How long does it take to charge the Class'Air CO2 sensor?

As a rough guide, the charging time for a Class'Air sensor is around 5 hours for a fully discharged sensor plugged into the mains. You can connect your sensor to a computer or USB port via the charging cable.

The Battery icon in the bottom right-hand corner of the sensor display indicates its charge level, or the battery percentage can be displayed on the screen using the buttons on either side.

For a more precise view of your sensor's remaining autonomy, the battery percentage and number of days of autonomy remaining can be viewed on the sensor's Class'Air settings module. You can download this module by clicking on the link. To connect your sensor, please refer to point 9.


How often are measurements refreshed?

In its factory configuration, the sensor measures every 10 minutes, in line with regulatory expectations for indoor CO2 monitoring.

Measurement steps can be set differently (see point 9) depending on the model. For Pedagogic and Recorder models, the frequency can vary from 1 minute to 1 hour, depending on requirements.

For the connected model, two frequencies are available: a measurement every 10 minutes or a measurement every hour.


How to display CO2 concentration in real time?

CO2 measurements can be output in three different ways:

All our CO2 sensors feature a display showing real-time CO2 concentration in PPM (parts per million) and other parameters measured by the sensor.
All our CO2 sensors also feature 3 colored LEDs (Green, Orange, Red) for rapid identification of air confinement in the room. In its factory setting, the sensor's threshold is :

  • Below 800ppm: air quality is fine
  • Between 800ppm and 1000ppm: air quality is average, so ventilate the area.
  • Above 1000ppm: air quality is poor, so ventilate or air out the area.

Our connected sensor enables real-time monitoring on the supervision platform thanks to automatic data feedback.


Is the CO2 sensor equipped with an audible alarm?

An audible alert can be activated by configuring the Class'Air sensor (see point 9 configuration). This alert consists of a series of 3 audible signals once the red CO2 threshold has been crossed.


Looking for more information about our Class'Air CO2 sensor?

Download product documentation here.


How can I retrieve measurements from the Class'Air CO2 sensor recorder?

Sensor measurements are retrieved in several stages:

  • Launch Class'Air software
    If you don't have it yet, you can download it from -> Class'Air software
  • Connect the Class'Air sensor to your computer using the USB cable supplied.
  • Synchronize the sensor by clicking on the icon to start detection.

You can then retrieve the data from your sensor by clicking on the blue "empty data" button.


How do I configure the Class'Air CO2 sensor?

The Class'Air sensor can be configured in two ways:

Directly on the sensor, thanks to its digital display and two buttons located on the screen, via a combination of keys to enter configuration mode.
You can find the full tutorial here "How to configure your sensor."

With the Class'Air configuration module
If you don't have it yet, you can download it from -> settings module.

Connect the Class'Air sensor to your computer using the USB cable supplied.
Synchronize the sensor by clicking on the icon to start detection.
Caution: for the recording sensor, the measurements must be emptied before configuring it! You can modify the parameters on the right of the module as you wish.

When configuration is complete, save the settings on the sensor by clicking on the checkmark in the top right-hand corner to apply the changes.

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