Smart Universal IAQ Instrument – Testo 400

Model No: Testo 400Part No: 0560 0400

The testo 400 is the universal measuring instrument for all IAQ professionals. Measure, analyze and document all IAQ and comfort level parameters using just one instrument – simply, conveniently and in compliance with the standards. High-quality measuring technology, intuitive measurement assistants, versatile documentation options and a comprehensive selection of IAQ probes make the testo 400 the perfect partner for your day-to-day work.

  • Smart, intuitive measurement programs including HVAC grid measurement as per EN ISO 12599 and ASHRAE 111, PMV/PPD and turbulence as per EN ISO 7730 and ASHRAE 55
  • High-precision, location-independent and integrated differential pressure sensor
  • Measure all IAQ-related parameters – with our wide range of probes for all IAQ measurements
  • Document measuring values directly on the customer’s site and send them by e-mail, or further analyze them using the testo DataControl PC software.


Impressive IAQ measurement technology

  • High-precision, location-independent, built-in differential pressure sensor
  • Integrated absolute pressure sensor
  • Measures all IAQ-related parameters: Flow velocity, temperature, humidity, pressure, illuminance, radiant heat, turbulence, CO2 and CO
  • Numerous connection options for probes: 2 x cable probes (TUC), 4 x Bluetooth® probes, 2 x type K thermocouple probes
  • Compatible with a wide range of available Bluetooth® and cable probes – so you’ll be equipped for any measuring task
  • Compatible with the testo 420 volume flow hood: Simply connect to the testo 400 via Bluetooth, measure volume flow at larger air inlets and outlets and manage all customer and measuring site data on site using one measuring instrument
  • For high-precision measurements and less downtime: Adjustment function at up to six measuring points for zero-error display, probe heads can be replaced without restarting the IAQ measuring instrument, high-quality probes with an intelligent calibration concept (probe calibration independent of the measuring instrument)
  • Long-term monitoring of the indoor air quality: Order the IAQ data logger for carrying out long-term measurements with the testo 400 IAQ measuring instrument. While the stand-alone data logger is carrying out the IAQ measurement, you can use the IAQ measuring instrument for measurements elsewhere

Smart, intuitive, practical: Measurement programs, measurement data management and operation

  • For error-free measurements in accordance with the standards: Smart, intuitive measurement menus and evaluation of readings provide optimum support for your measuring task. Use the measurement programs for standard-compliant measurements: HVAC grid measurement as per EN ISO 12599 and ASHRAE 111, PMV/PPD as per EN ISO 7730 and ASHRAE 55, draught and turbulence as per EN ISO 7730 and ASHRAE 55, WBGT measurement as per DIN 33403 and EN ISO 7243, NET measurement as per DIN 33403
  • Complete the measurement along with full documentation including photos, comments and your own logo at the customer’s premises, and send by e-mail (via WLAN)
  • Customer and measuring point management is carried out on the measuring instrument itself – for efficient work on site.
  • Smart-touch display for intuitive operation of the IAQ measuring instrument
  • testo DataControl PC software for further analysis, archiving and documentation of measurement data on your computer
  • Built-in WLAN and Bluetooth® interfaces: Send measurement reports directly on site or print them out with a suitable printer

Scope of delivery

1 x testo 400 universal IAQ instrument, including transport case for air flow measurements, connection hose, mains unit with USB cable, calibration protocol and instruction manual.

Technical Data

Temperature – NTC

Measuring range

-40 to +150 °C


±0.2 °C ±1 Digit (-25 to +74.9 °C)

±0.4 °C ±1 Digit (-40 to -25.1 °C)

±0.4 °C ±1 Digit (+75 to +99.9 °C)

±0.5 % of mv ±1 Digit (Remaining Range)


0.1 °C

Temperature – TC Type K (NiCr-Ni)

Measuring range

-200 to +1370 °C


±(0.3 °C + 0.1 % of mv) ±1 Digit


0.1 °C

Differential pressure (internal sensor) – Piezoresistive

Measuring range

0 to +200 hPa


±(0.3 Pa + 1 % of mv) ±1 Digit (0 to 25 hPa)

±(0.1 hPa + 1.5 % of mv) ±1 Digit (25.001 to 200 hPa)


0.001 hPa

Absolute Pressure (internal sensor and external probe)

Measuring range

700 to 1100 hPa


±3 hPa


0.1 hPa

General technical data


510 g (instrument)


210 x 95 x 39 mm ((LxWxH))

Operating temperature

-5 to +45 °C

Product-/housing material


Protection class


Connectable probes

4 x digital Bluetooth® probe or testo Smart Probe; 2 x digital probe with fixed cable or temperature probe NTC with fixed cable (via Testo Universal Connector – TUC); 2 x temperature probe TC type K with fixed cable

Product colour


Camera image size

Main camera: 8.0 MP; Front camera: 5.0 MP

Battery life

approx. 10 hrs continuous operation

Display type

5.0″ touch display, HD 1280*720 pixels, IPS (160 k)

Power supply

Rechargeable li-ion battery (5550 mAh)


Bluetooth®; USB; WLAN


2 GB; 1,000,000 measuring values

Storage temperature

-20 to +60 °C

*TUC connection (Testo Universal Connector): For the connection of fixed cable digital probes and NTC probes.



 Datasheet Download.  Instruction Manual Download

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