Sensors to measure CO2, temperature and relative humidity in HVAC applications. Measuring carbon dioxide (CO2) levels in building environments is crucial for ensuring indoor air quality. Elevated CO2 concentrations can indicate inadequate ventilation, potentially leading to discomfort and impaired cognitive function among occupants. Monitoring CO2 helps identify areas with insufficient fresh air exchange, allowing for timely adjustments to ventilation systems to enhance overall indoor comfort. Additionally, proper CO2 measurement aids in the early detection of potential issues, such as malfunctioning HVAC systems or the presence of indoor pollution sources, contributing to a healthier living or working environment. Regular CO2 monitoring aligns with energy efficiency goals by optimizing ventilation rates based on actual occupancy, promoting both occupant well-being and sustainable building practices.