CO2 Detector: Review & Recommendations

Welcome to our big CO2 detector test 2020, where we present you all CO2 detectors that we have tested in detail. We have provided you with detailed background information

We want to make your purchase decision easier and help you to find the best CO2 detector for you.

You can also find answers to frequently asked questions in our guide. If available, we also offer you interesting test videos. Furthermore, you will also find some important information on this page that you should pay attention to if you want to buy a CO2 detector.

The most important facts in brief

  • A CO2 detector measures the amount of carbon dioxide in the air and sounds an alarm when a certain concentration is reached.
  • In principle, a certain amount of carbon dioxide in the air (approx. 500-1000 ppm) is normal and harmless. However, higher amounts (from 2500-3000 ppm) can cause headaches or breathing difficulties.
  • In closed rooms the air deteriorates imperceptibly. A CO2 detector alerts you to too high a concentration of carbon dioxide, reminds you to ventilate and saves you from annoying headaches caused by carbon dioxide.

CO2 detector test: Editors’ favourites

  • The best multifunctional CO2 detector
  • The best portable CO2 detector
  • The best CO2 detector with recording function

The best multifunctional CO2 detector

Extech’s air quality and carbon dioxide monitor gives you information about CO2 concentration, temperature, humidity, date and time. Another special feature are the user-defined high/low alarms. So you can decide for yourself when you want to be reminded to air out.

So if you are looking for a multifunctional CO2 detector with user-defined high/low alarms and a sensationally fast measuring rhythm (every 2 seconds), this device is the perfect choice for you.

The best portable CO2 detector

The AirControl Mini CO2 measuring instrument from TFA-Dostmann is perfectly suited for monitoring the CO2 concentration and room temperature in all indoor areas.

By means of an LED traffic light display you can always see whether the air quality in a room is optimal, medium or poor. Thanks to the USB connection, this model is mobile and flexible. So if you are looking for a portable CO2 detector, this device is the right choice for you.

The best CO2 detector with recording function

The CO2 measuring device AirControl 5000 from TFA-Dostmann shows you the current air quality, the current time as well as room temperature and humidity. A LED traffic light display shows you the current CO2 level.

The special feature of this device is the storage and graphic display of the measured CO2 values. By means of a 24-hour graphic, you get a practical overview of the measured values and can also read the maximum and minimum values of the carbon dioxide concentration.

Guide: Questions you should consider before buying a CO2 detector

What is a CO2 detector?

How is carbon dioxide produced and why should you measure it?

Carbon dioxide is a compound consisting of carbon and oxygen. About 0.04 percent of our air is carbon dioxide. Carbon dioxide is produced, for example, by the combustion of fossil fuels such as coal, natural gas or oil.
Carbon dioxide can also be produced by cellular respiration in plants, animals or humans. A single person alone breathes out an average of 15-20 litres of air per hour during a sedentary activity, thereby adding more than a hundred times the amount of CO2 to the air.

Thus, the daily carbon dioxide emissions of a single person add up to the amount emitted by a small car over a distance of ten kilometres.

Carbon dioxide in rooms is not dangerous for the environment, but in too high a concentration it affects the well-being of all of us. For an optimal indoor climate, especially in rooms where many people are present, a CO2 detector is definitely an advantage.
In the following video you will get more information about carbon dioxide and its consequences for our environment

For whom is a CO2 detector suitable?

A CO2 detector is basically suitable for everyone. However, unlike smoke detectors, there is no obligation in private households to install a CO2 detector.
The installation of a CO2 detector is particularly important in the following commercial sectors / localities, as larger quantities of CO2 can accumulate here and this represents a considerable health hazard:

Wine cellar
Feed Silos

With a CO2 detector you can also save energy in your own home. Many households have demand-controlled ventilation. You can adjust this according to the readings of the CO2 detector. This means that you always ventilate when the carbon dioxide content has reached a certain threshold.

Did you know that especially residents of new and well-insulated premises should keep a special eye on the CO2 concentration?
Due to the reduced exchange with fresh outside air, a larger amount of carbon dioxide is very quickly produced in closed, well-insulated rooms.

Up to what CO2 value is the air considered clean?

The concentration of carbon dioxide measured in ppm (parts per million) is very closely related to air quality. In the following table we give you an overview of the CO2 values and the resulting air quality.

As a simple guide you can take 1000 ppm. This value should not be exceeded by the carbon dioxide concentration of the room air.

What is the difference between a CO2 detector and a CO detector?

In addition to carbon dioxide measuring devices, a CO detector is also useful for checking air quality. A CO detector alerts you as soon as the carbon monoxide concentration in the room exceeds a certain level that could be harmful to you.
Carbon monoxide is a colourless, poisonous and odourless gas that is produced by the combustion of carbon-containing substances. Even low concentrations of carbon monoxide can lead to carbon monoxide poisoning without being noticed.

To check the air quality, we recommend an additional CO detector in addition to a CO2 detector.

Note that a CO detector and a CO2 detector measure different gases. They are two completely different devices that must be purchased separately.
Unlike CO detectors, which are mounted on the ceiling like smoke detectors, you should place a CO2 detector near the floor. This makes sense because the gas carbon dioxide is heavier than air and is deposited on the floor.

Where can I buy a CO2 detector?

CO2 detectors can be bought in department stores, DIY stores, consumer electronics stores or in numerous online shops. In addition, some discounters offer CO2 detectors from different manufacturers as part of special offer weeks.
According to our research, most CO2-detectors are sold via these online shops:

What does a CO2 detector cost?

Basically there is a big price difference between CO2 detectors. Depending on the manufacturer, supplier or type of device, the prices for one and the same model can vary considerably.

An online price comparison is highly recommended

CO2 detectors cost between 70 and 200 euros. Portable CO2 detectors are the cheapest. Some models are available for as little as 70 euros. Multifunctional or recording CO2 detectors are usually considerably more expensive. Here the price is approximately between 130 and 200 euros.

In the following table we have summarized the prices for the different models of CO2 detectors:

How many CO2 detectors should you buy?

In principle, CO2 detectors are useful where many people stay for a long time. For example, in living rooms, classrooms and offices.
Air quality should also play a major role in children’s rooms. Here it is recommended to install a CO2 detector, which you can connect to an app on your mobile phone. This allows you to check the values anywhere and anytime.

Decision: What types of CO2 detectors are there and which one is right for you?

If you want to buy a CO2 detector, there are three models you can choose between:

  • Multifunctional CO2 detector
  • Recording CO2 detector
  • Portable CO2 detector

What are the advantages and disadvantages of the individual models?

Multifunctional CO2 detector

Multifunctional CO2 detectors are not only limited to the measurement of carbon dioxide, but also show you additional values such as temperature or humidity. Some of these models also have a clock and alarm function.

However, these devices only cover a CO2 content of up to 5000 ppm. This is however completely sufficient for living and sleeping areas, schools or offices. The measuring rhythm is also somewhat slower with this variant of a CO2 detector than with other models.


Most configurable alarm
Versatile in use


Slow measurement rhythm
Measuring range goes only up to 5000 ppm
No recording function

Recording CO2 detector

If an exact overview of the development of the CO2 concentration is needed, one should take a look at recording CO2 detectors. These models store the measured CO2 content of the room air and show the air quality trend on their display.

Recording CO2 detectors usually cover a larger measuring range than multifunctional devices and have a faster measuring rhythm. They are therefore also somewhat more expensive to purchase.

The acquisition of a recording CO2 detector makes sense primarily where precise and regular monitoring of the CO2 content is required. Examples of this are cellars with wood gasification boilers or also the possession of a pellet heating system.


Particularly precise measurement (fast measuring rhythm)
Wide measuring range (up to 10000 ppm)
Most configurable alarm


Very high price

Portable CO2 detector

Especially if several rooms are to be examined with regard to CO2 concentration, the battery or rechargeable battery operated C02 detector is a good choice. A portable CO2 detector is also the perfect companion for irregular checks of rooms or in caravans / motor homes.

Portable CO2 detectors are also characterized by a particularly fast measuring rhythm and are significantly cheaper to purchase than other models of CO2 detectors.


Mobile use
Wide measuring range (up to 10000 ppm)
Favorable purchase price


Works only with accessories (battery or rechargeable battery)
Has no recording function

Purchase criteria: You can compare and evaluate CO2 detectors based on these factors

  • LED display
  • Evaluation of the measured values via App
  • Recording function
  • Configurable alarm
  • Measuring range / measuring rhythm

LED display

With the help of an LED display you can see at first glance and also from a distance how the CO2 level is.

Many models now have an LED traffic light display. This gives you a direct impression of the CO2 concentration in the room air. We therefore recommend that you buy a CO2 detector with an LED display as well as an LED traffic light display.

Evaluation of the measured values via App

Various CO2 detectors now offer this function. This is useful if you want to check the CO2 values in your home while you are on the road. It can also be an advantage during longer holidays to be able to check the CO2 values at home.

This device is particularly worthwhile for houses with a pellet heating system or other sources of danger for an increased energy consumption.

Recording function

With a recording function you can see the values of the last 24 hours as well as the current maximum and minimum values of the CO2 concentration of the room air.

This makes it easier for you to find out how often you should ventilate and how long it takes for the carbon dioxide level to return to normal. Particularly in buildings where there are a lot of people, a CO2 detector with recording function can provide a great deal of information about optimal ventilation.

Configurable alarm

A configurable, user-defined alarm is another purchase criterion that you should think about before buying a CO2 detector.

With the help of a configurable alarm, you can set your own alarm values and know at any time and above all at an early stage what the carbon dioxide content of the air in the corresponding interior is.

If the CO2 detector is connected to the ventilation system, you can ensure optimal ventilation around the clock, even when you are not on site.

Measuring range / measuring rhythm

Measuring range and measuring rhythm are also important if you are considering buying a CO2 detector. Usually CO2 detectors have either a measuring range up to 5000 ppm or a measuring range up to 10000 ppm.

Depending on the place of use, it is important to weigh up how accurate the measurement results should be. This is where the measuring rhythm comes into play. The more often measurements are taken, the more accurate the results will be.

For exact measuring results, especially in buildings where many people are present or for professional use in gastronomy or agriculture, we recommend a CO2 detector with a large measuring range and a fast measuring rhythm.

Trivia: Worth knowing facts about CO2 detectors

What to do when the CO2 detector sounds the alarm?

First of all, you should open the window quickly and ventilate well. Most of the time, the problem of too high carbon dioxide concentrations

To prevent this, however, you should ventilate regularly and above all correctly. We recommend that you open the windows completely, regardless of the season, 3-4 times a day for about 10 minutes.

Can I also use a CO2 detector as a fire alarm?

No, CO2 detectors and fire or smoke detectors have different functions because they work with different sensors. A CO2 detector measures the carbon dioxide content and shows you the corresponding value.

A smoke or fire detector, on the other hand, sounds the alarm as soon as smoke is detected.

In the following video you will get more information about the installation of smoke detectors.