The universal air velocity & IAQ measuring instrument testo 400

Fast on
Fast on
Simply exchange probes during the measurement without a re-start. 
Measurement assistant
Measurement assistant
Smart support for error-free measurement. 
Universally applicable
Universally applicable
Wide range of probes for all of your air flow & IAQ measurements. 
Always ready to go
Always ready to go
Probes can be calibrated independently of the measuring instrument. 
Saving time
Saving time
Finish measurement with complete documentation directly on site with the customer. 
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Click now to see how the testo 400 works!

With an intuitive touch display
and intelligently designed operation,
the testo 400 helps you
to carry out all measurements
faster and more efficiently
than ever before.

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IAQ measuring instrument with touch operation
IAQ measuring instrument with touch operation

Would you welcome some advice?

In the online configurator, you can find out quickly and easily which combination of measuring instrument, probe and accessories best suits your requirements.

How to contact us?

Do you have any questions? We're happy to help you.

Regional Office (Singapore, Malaysia, Indonesia)

What do you need to measure?

testo 400 brochure

testo 400 brochure
All information on the measuring instrument, probes and accessories in a compact download.

All testo 400 measurement menus.

testo 400 measurement
The testo 400 supports your daily work with these measurement menus.

Click now to see how the testo 400 works!

With an intuitive touch display
and intelligently designed operation,
the testo 400 helps you
to carry out all measurements
faster and more efficiently
than ever before.

testo-400-Klickdummy_1_Start-Ansicht_oben.jpg
testo-400-Klickdummy_1_Start-Ansicht_unten.jpg
testo-400-Klickdummy_Image01_2000x1500px.jpg
smarttouchbutton.png
Play
Play
 
Stop
Stop
 

testo 400 – the multitasker for IAQ professionals

  • Measures all IAQ-related parameters: Flow, temperature, humidity, pressure, illuminance, radiant heat, turbulence, CO₂ and CO
  • High-precision, location-independent and integrated differential pressure sensor
  • High-quality digital probes and an intelligent calibration concept
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testo-400-Klickdummy_2_Basic-View_unten.jpg
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Smart support through stored measurement menus and evaluation of measuring values according to the traffic light principle – for error-free measurements

  • HVAC grid measurement in accordance with EN ISO 12599 and ASHRAE 111
  • PMV/PPD in accordance with EN ISO 7730 and ASHRAE 55
  • Draught and degree of turbulence in accordance with EN ISO 7730 and ASHRAE 55
  • WBGT measurement in line with DIN 33403 and EN ISO 7243, NET measurement in accordance with DIN 33403
testo-400-Klickdummy_3_Hauptmenue_oben.jpg
testo-400-Klickdummy_3_Hauptmenue_unten.jpg
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Determination of volume flow in ducts using grid measurement in accordance with EN 12599

  • For all flow velocity probes (hot wire, vane) and Pitot tubes
  • Input of duct geometry and duct apertures
  • Single-point or timed measurement
  • Calculation of measurement uncertainty according to EN 12599
  • Automatic display of insertion depths for traversing duct
  • Duct distribution for rectangular ducts according to the trivial method, and for circular ducts according to the centroidal axis method.
testo-400-Klickdummy_4_Messprogramm_oben.jpg
testo-400-Klickdummy_4_Messprogramm_unten.jpg

Determination of volume flow in ducts using grid measurement in accordance with EN 12599

  • For all flow velocity probes (hot wire, vane) and Pitot tubes
  • Input of duct geometry and duct apertures
  • Single-point or timed measurement
  • Calculation of measurement uncertainty according to EN 12599
  • Automatic display of insertion depths for traversing duct
  • Duct distribution for rectangular ducts according to the trivial method, and for circular ducts according to the centroidal axis method.
testo-400-Klickdummy_5_RLT-Netzmessung(1)_oben.jpg
testo-400-Klickdummy_5_RLT-Netzmessung(1)_unten.jpg

Determination of volume flow in ducts using grid measurement in accordance with EN 12599

  • For all flow velocity probes (hot wire, vane) and Pitot tubes
  • Input of duct geometry and duct apertures
  • Single-point or timed measurement
  • Calculation of measurement uncertainty according to EN 12599
  • Automatic display of insertion depths for traversing duct
  • Duct distribution for rectangular ducts according to the trivial method, and for circular ducts according to the centroidal axis method.
testo-400-Klickdummy_6_RLT-Netzmessung(2)_oben.jpg
testo-400-Klickdummy_6_RLT-Netzmessung(2)_unten.jpg

Work efficiently on site – no workarounds, just on to the next job

  • Manage all relevant customer data including measurement locations directly in the instrument
  • Complete and send measuring values with full documentation, including photos, comments and your own logo directly on site – and get to the next job faster
testo-400-Klickdummy_7_Protokoll-Ansicht_oben.jpg
testo-400-Klickdummy_7_Protokoll-Ansicht_unten.jpg
testo-400-Klickdummy_Image04_2000x1500px.jpg

Work efficiently on site – no workarounds, just on to the next job

  • Manage all relevant customer data including measurement locations directly in the instrument
  • Complete and send measuring values with full documentation, including photos, comments and your own logo directly on site – and get to the next job faster
testo-400-Klickdummy_8_Protokoll-Ansicht_oben.jpg
testo-400-Klickdummy_8_Protokoll-Ansicht_unten.jpg
testo-400-Klickdummy_Image04_2000x1500px.jpg