Foto der fertigen CO2-Ampel

CO2meter: Ventilation against Covid-19

Scientists build CO2meters for the HFT

HFT scientists build inexpensive CO2meters for timely ventilation in HFT rooms and contribute to limiting the risk of infection in corona times. They put the building instructions online for everyone - including schools, industry and private individuals.

CO2meters indicate in good time when it is time for fresh air again. Both universities and schools currently require many such devices for the winter.


Currently there are hardly any CO2meters available on the market, so we have decided to build some ourselves at a reasonable price.

Dr. Tobias Erhart,
Technical Director of the Institute for Applied Research (IAF) of the HFT

The team has now assembled 25 such devices, which are distributed to different rooms in the HFT - more devices will follow. Available components were used for the newly developedCO2meters. "For us, the most important thing was that the device is reliable, good and affordable," emphasizes Tobias Erhart. According to his estimates, the material costs are around 60 euros per unit. In times of a corona pandemic, ventilation is essential to limit the Covid-19 risk in rooms at universities and schools. Because: with every breath, every cough or sneeze, not onlyCO2 is emitted, but also aerosols, which can be contaminated with corona viruses. The HFT team consisting of Tobias Erhart, Robert Otto, Jonas Stave, Myriam Guedey and Eric Duminil assembled the hardware and developed the software. The team from the carpentry workshop of Faculty A around Albert Stöcker created the housings with the help of laser-cut Plexiglas parts. The student team Benjamin Hueber and Nathalie Heimsch came to the assistance of Benjamin Hueber and Nathalie Heimsch for the final assembly, soldering of the components and joining of the housing parts. The team also prepared a step-by-step guide so that schools, companies and private individuals could copy such aCO2meter for their own use.

TheCO2meter from the HFT forge has attracted the attention of cooperation partners from industry. Bosch, for example, wants to use a modified version of the device in its open-plan offices and evaluate the data collected there together with the HFT. The idea of aCO2meter is not new, but the HFT researchers have equipped the device with additional technical details. "With integrated data acquisition via the network, we are going one step further," emphasizes Tobias Erhart. The newly integrated data acquisition sends the measured data to a central measurement server. This enables critical rooms to be identified and also allows conclusions to be drawn about thermal comfort and potential energy savings. The university's own information center (IZ) provided a special WLAN for theCO2meters for this purpose. Already in the imaF project (intelligent motor-driven windows for the natural ventilation of buildings) at the HFT, an automatic control for windows based on Arduino was developed as a cost-effective, open approach. The aim was to optimise thermal comfort and ensure indoor air hygiene by means of window ventilation. TheCO2meter will also be used in other projects at the HFT, such as the iCity project Smart Public Building for networking buildings.

Instruction CO2 light-system:

Good to know

Ventilation is a major issue, particularly in commercial and public buildings such as schools, universities, administrative and office buildings, restaurants and hotels. The practical suitability of controlled ventilation (KNL) based on electromotive windows is also proven by the HFT study from 2016 "KonLuft" - Energy Efficiency of Buildings by HFT. The study was carried out in cooperation with the project partner ZVEI - Central Association of the German Electrical and Electronic Manufacturers' Association - and the project management agency Federal Ministry of Economics (BMWi) and Project Management Jülich (PTJ).

"KNL can help to increase thermal comfort in buildings with lower investment and operating costs compared to central ventilation systems. It can also make a valuable contribution to indoor air hygiene," emphasizes Dr. Tobias Erhart, who wrote the study together with Prof. Ursula Eicker, Daniel Gürlich, Max Haag and Dr. Tobias Schulze.

The central findings of this study are that KNL systems save around twelve percent of investment costs compared to fan-assisted ventilation systems with heat recovery. Over a period of 20 years, around 50 percent less operating and maintenance costs are incurred. KNL also has advantages in terms of climate and environmental friendliness: Low energy consumption saves resources and reducesCO2 emissions.

Publish date: 26. November 2020 By Susanne Rytina ()