To briefly summarize: CO₂ indoor monitoring is important to ensure well-being and minimize drops in cognitive performance of people. Demand-controlled ventilation (DCV) systems leverage CO₂ sensors to perfectly balance good indoor air quality with high energy efficiency. Therefore, demand-controlled ventilation reduces the carbon footprint and the associated energy costs of buildings significantly. Additionally, CO₂ sensors help monitoring indoor air quality in air treatment devices, smart home devices and other applications.