Testo 400 Universal Indoor Air Quality Instrument

The Testo 400 is a universal indoor air quality (IAQ) measuring instrument designed for HVAC commissioning engineers and air quality specialists who need to measure, analyse and document multiple parameters from a single device. Flow, temperature, humidity, differential pressure, illuminance, radiant heat, turbulence intensity, CO₂ and CO — all covered with interchangeable smart probes and on-site app-based reporting.

The Testo Smart App connects wirelessly for live data display, logging and PDF report generation on site. For the hot wire probe kit configuration, see the Testo 400 Air Flow Kit (Hot Wire). See all test and measurement instruments at HVAC Shop AU.

Key Features

• Measures flow, temperature, humidity, CO₂, CO, pressure, illuminance, radiant heat and turbulence
• Interchangeable smart probes — auto-recognised on connection
• Testo Smart App — live display, data logging and PDF report generation
• Standards-compliant IAQ and comfort level measurement
• Single instrument replaces multiple meters

Typical Applications

• HVAC commissioning and performance verification
• Indoor air quality assessment and compliance reporting
• Workplace comfort level measurement
• Ventilation system balancing and airflow measurement

What’s Included

• Testo 400 instrument
• Batteries
• Calibration certificate
• Instruction manual