Carbon dioxide (CO2) concentration varies with the number and activity level of people in any given space inside a building. A too high CO2 concentration can lead to fatigue and reduced concentration levels – or even worse, ‘Sick Building Syndrome’ which causes symptoms such as headaches, irritation of the eyes, nose, and throat, itchy skin, and nausea. Therefore, proper ventilation is imperative for the health and safety of building occupants. Monitoring CO2 levels isn’t just about air quality – it can also help with your energy usage, as it is an indicator of over or under ventilation of your facility. Installing CO2 sensors in key areas of the office, such as meeting rooms, lunchrooms, break rooms, and similar areas can contribute to sustainability goals.
CO2 level rises with the number of people
When a room is occupied, the CO2 produced by people increases the concentration in the room from a normal minimum of about 400ppm to higher levels. This increase starts to get noticeable around 800ppm and can affect people’s health negatively when it exceeds 2000ppm. The traditional way to deal with this problem is to set up the airflow to a room so that at maximum occupancy, the CO2 concentration does not exceed certain critical levels. As most of these rooms are not occupied all the time, a lot of energy is wasted on unnecessary ventilation.
Rule of thumb design parameters
The building industry developed rule of thumb design parameters for this. Ventilation systems are usually used based on simple air exchange standards and rules of thumb without information about the actual CO2 levels. For example, ventilation is controlled based on a calculation of the geometry of space. To determine the amount of air exchange required for your ventilation equipment, calculate the volume of the room (LxWxH) and divide it by the number of minutes per air change. Doing this for each room takes a lot of time and is often inaccurate, which means that a lot of energy is still wasted. With real-time monitoring of CO2 via sensors, you can significantly improve this aspect and decrease energy use.
By implementing CO2 sensors, facility managers get insight into the CO2 level in each room and can adjust the ventilation accordingly. The system can also automatically ventilate the room based on the actual CO2 levels, also known as demand-driven ventilation. Without demand-driven ventilation, the ventilation will always run at the same settings, even if the building is empty. However, with demand-driven ventilation, there is huge potential to achieve energy savings. This is an easy way to increase the operating efficiency of your building while significantly reducing electricity costs and energy waste.