Best CO2 Monitors for Schools & Classrooms

Classrooms are among the most CO2-impacted indoor spaces because they pack many occupants into relatively small rooms, often with outdated HVAC systems. Studies have found CO2 levels in classrooms frequently exceeding 2,000 ppm, which correlates with significantly reduced student attention, learning outcomes, and test performance. Since the pandemic, many schools have adopted CO2 monitoring as a practical proxy for ventilation adequacy to reduce airborne pathogen transmission. Effective classroom monitors need to be affordable enough to deploy widely, easy for teachers to interpret at a glance, and durable enough for school environments. Our top picks balance cost, accuracy, and usability for education settings.