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The universal air velocity & IAQ measuring instrument testo 400
Smarter. Faster. Better: The new generation of air flow and IAQ measurement technology
Thanks to its easy handling, it is more convenient than ever before to carry out all measurement tasks in air conditioning and ventilation.

Everything under control at the touch of a finger
You operate the testo 400 with its Smart-Touch technology just as intuitively as your smartphone.

Wireless measurement with one click
You simply start and stop measurements with just one button on the probe handle.

Always have the right probe at your fingertips
Die neuen flexiblen Bluetooth- und Kabelsonden sind vollständig miteinander kompatibel.
With the testo 400, you save time and deal with customer administration and reporting directly on site, whereas previously this was only possible with software and a PC.

Customers and measuring points are always at hand
You can save data directly in the measuring instrument, manage them and re-use them for repeated measurements.

Beat the paperwork
Create professional reports, with data, images and comments on site and send them directly by WLAN/Bluetooth.

The App for your PC
The measurement data management and analysis software testo DataControl for the most detailed analysis and reporting in the office is included in delivery.
The more demanding the measurement, the more the integrated measurement assistant supports you in configuration, implementation and analysis - for error-free results.

IAQ measurements according to EN12599 and ASHRAE 111

PMV/PPD measurement in accordance with EN ISO 7730 and ASHRAE 55

Turbulence measurement in accordance with EN ISO 7730
Individual applications
See for yourself how the testo 400 can make your job easier.
Application examples
See for yourself how the testo 400 can make your job easier.
Downloads
Download: Practical guide: Comfort level measurement at the workplace H4>

Our practical guide on comfort measurement at the workplace answers the following questions for you:
- What is thermal comfort?
- Which measurement technology is suitable?
- How do you carry out a measurement?
Download: Practical guide: Air flow measurements in ducts according to DIN EN 12599 H4>

Find out how to use the testo 400 for air flow measurements in ducts by reading the practical guide:
- Selecting measurement sites
- Differences between measurement methods
- And evaluating measurement values
Download:Overview of all measurement menus in the measurement assistant H4>

Find out how the integrated measurement assistant supports you thanks to pre-configured measurement programmes.