Measuring indoor air quality and comfort level

The testo 400 allows you adjust the indoor climate to comply with standards, thus minimising the risk of staff absences due to illness. With the testo 400 and its extensive probe portfolio, you can determine all relevant parameters quickly, reliably, and intuitively.

  • Intuitive measurement menus
    The testo 400 actively assists you in taking standard-compliant measurements. It guides you step by step through the comfort level measurement and assists you in evaluating the measurement results.
  • Wireless convenience
    Numerous probes for comfort level and indoor air quality are also available in the wireless Bluetooth variant. This means less stress for you and more space in the measuring case. 
  • IAQ long-term measurement
    The IAQ data logger can be used independently for long-term measurements with up to six different probes after it has been programmed using testo 400.
  • Practical accessories
    Use the measuring tripod for comfort level measurements to position the compatible measuring instrument and the probes in compliance with the standards at all times.

Standard-compliant comfort level measurement

The testo 400 allows you to check all parameters for indoor air quality and comfort levels in compliance with the latest regulations and standards: 

  • Objective statement on thermal comfort thanks to PMV/PPD measurement
  • Standard-compliant determination of turbulence, draughts, and indoor air quality
  • Determination of comfort levels at hot work stations with the WBGT measurement


Kits, probes, and accessories for IAQ and comfort level measurement

testo 400 comfort kit

testo 400 comfort kit
To the kit
  • testo 400 IAQ measuring instrument and testo DataControl software
  • CO2 probe with Bluetooth, including temperature and humidity sensor
  • Turbulence probe
  • Globe thermometer
  • Measuring tripod with bag
  • Comfort case

IAQ data logger

IAQ data logger testo 400
To the kit
  • For long-term measurement of indoor air quality
  • Programming and readout with testo 400 
  • After programming, it works completely independently of testo 400



testo 400 WBGT kit

testo 400 WBGT kit
To the kit
  • For assessment of workplaces exposed to heat according to ISO 7243 and DIN 33403-3
  • Consists of: Globe thermometer, ambient temperature and wet bulb temperature probe, plug-in head cables, tripod, and case


More probes and accessories

testo 400 probes and accessories
Fully exploit the potential of the testo 400.

Comfort measurement (PMV/PPD)

Long-term measurement with the testo 400 and IAQ data logger

Valuable measuring facts about testo 400

Measurement menus
of testo 400

With these pre-installed measurement menus, the testo 400 can assist you in carrying out measurements highly efficiently, without measurement errors, and in compliance with standards.

testo 400 brochure

Everything you need to know about the testo 400 universal IAQ instrument in one concise brochure

Application example
WBGT kit

Easy and reliable evaluation of heat-affected workplaces with the help of the WBGT kit from Testo.

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