The testo 535 is a professional-grade CO₂ measuring instrument designed for quick and accurate evaluation of indoor air quality. It features an integrated infrared sensor for long-term stability and high reproducibility, making it ideal for consistent indoor air monitoring, especially in schools, offices, and workplaces.

Through its connection with the testo Smart App, the instrument allows for effortless configuration, data visualisation (graph and table formats), second-screen functionality, and automatic documentation of measurement data. The App enhances usability by enabling fast setup and intuitive operation, while also allowing storage and export of results for analysis or reporting.

With built-in audible alarm alerts when CO₂ thresholds are exceeded and functions like time and point averaging, the testo 535 ensures you can act quickly to maintain a healthy and comfortable indoor environment. Compact and user-friendly, it’s the ideal tool for professionals responsible for HVAC systems, facility management, and workplace health.