Delivery Scope

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

Universal IAQ instrument - testo 400
Model No: testo 400 Part No: 0560 0400

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

  1. 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
  2. High-precision, location-independent and integrated differential pressure sensor
  3. Measure all IAQ-related parameters – with our wide range of probes for all IAQ measurements
  4. 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


Testo 400 universal IAQ instrument – features

Impressive IAQ measurement technology

  1. High-precision, location-independent, built-in differential pressure sensor
  2. Integrated absolute pressure sensor
  3. Measures all IAQ-related parameters: Flow, temperature, humidity, pressure, illuminance, radiant heat, turbulence, CO2 and CO
  4. Numerous connection options for probes: 2 x cable probes (TUC), 4 x Bluetooth® probes, 2 x type K thermocouple probes
  5. Compatible with a wide range of available Bluetooth® and cable probes – so you’ll be equipped for any measuring task
  6. 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)
  7. 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

  1. 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
  2. Complete the measurement and full documentation including photos, comments and your own logo on site at the customer’s premises, and send by e-mail (via WLAN)
  3. Customer and measuring point management is carried out in the measuring instrument itself – for efficient work on site
  4. Smart-touch display for intuitive operation of the IAQ measuring instrument
  5. testo DataControl PC software for further analysis, archiving and documentation of measurement data on your computer
  6. Built-in WLAN and Bluetooth® interfaces: Send measurement reports directly on site or print them out with a suitable printer
Temperature - NTC
Measuring range -40 to +150 °C
Resolution 0.1 °C
Accuracy ±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)
Temperature - TC Type K (NiCr-Ni)
Measuring range -200 to +1370 °C
Resolution 0.1 °C
Accuracy ±(0.3 °C + 0.1 % of mv) ±1 Digit
Differential pressure (internal sensor) - Piezoresistive
Measuring range -100 to +200 hPa
Resolution 0.001 hPa
Accuracy ±(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)
Absolute Pressure (internal sensor and external probe)
General technical data
Protection class IP40
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
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)
Interface Bluetooth®; USB; WLAN
Memory 2 GB; 1,000,000 measuring values

Delivery Scope

Testo 440 air velocity and IAQ measuring instrument, 3 x AA batteries, USB cable and calibration protocol

IAQ Measuring Instrument - testo 440
Model No: testo 440 Part No: 0560 4401

Precise, reliable measurement of all air velocity and IAQ parameters with just one measuring instrument: the multifunction measuring instrument features intuitive operation with clearly structured measurement menus. Adjusting air conditioning and ventilation systems, monitoring air quality or carrying out comfort level measurements – thanks to versatile options for combining with high-quality, digital probes, you are ideally equipped to carry out your measuring task (please order probes separately)

  1. Intuitive: clearly structured measurement menus for volume flow, degree of turbulence, cooling/heating output, mould detection and long-term measurement, such as CO₂
  2. Wireless: Bluetooth® probes for extra convenience when measuring and less cable clutter in the measuring case (please order probes separately)
  3. Clear overview: large graphic display with parallel display of 3 readings
  4. Safe and reliable: internal data storage and USB port for data export


Testo 440 air velocity and IAQ measuring instrument in combination with high-quality probes to measure and store all air velocity and IAQ parameters (please order probes separately). Up to 3 probes can be connected simultaneously: a Bluetooth probe, a wired probe and a temperature probe with type K thermocouple connector. Automatic probe detection and clearly structured measurement menus guarantee simple operation and will make your day-to-day work easier.

Measure in just a few clicks with the testo 440 multifunction measuring instrument

Carry out your measurements quickly and easily: the air velocity and IAQ measuring instrument automatically detects each connected probe. This means that there is no need for you to manually reset the parameters when changing probes. Clearly structured measurement menus for measuring the volume flow in ducts/at outlets, funnel measurement, measuring the degree of turbulence, determining the cooling/heating output, mould detection and long-term measurement provide you with optimum support during your day-to-day work.

Wireless and space-saving: more applications, less equipment

Endlessly versatile: a universal handle can be connected to all probe heads – so you can master more applications using less equipment and save space.

The Bluetooth handle makes it more convenient to carry out your measurement and guarantees less cable clutter in the case. It makes it possible to carry out measurements without any bothersome cable connection and it transfers readings up to a distance of 20 m. Or as a practical alternative, use the cable handle to connect testo probe heads. This is an advantage if Bluetooth signals are not permitted.

Practical measurement data management

The multifunction measuring instrument stores up to a max. 7500 measurement protocols, which can be read via a USB port and further processed as a CSV file on your computer (e.g. with Excel). With the testo BLUETOOTH/IRDA printer (please order separately), you have the option of producing a report printout of the measurement data directly on site.

Intelligent calibration concept for maximum precision

You can rely on accurate measurement results when using our digital probes, because the measuring instrument makes measurement uncertainty a thing of the past. You only need to send the probes in for calibration. The multifunction measuring instrument can therefore remain in continuous use.

Advantages of measuring with the testo 440 air velocity and IAQ measuring instrument

Precise and reliable in ducts and at air outlets

  1. Large range of connectable probes: hot wire and vane probe (Ø 16 mm) for measurements in ducts; large vane probes of Ø 100 mm for measurements at air/ceiling outlets
  2. Calculate volume flow quickly: in the measurement menu, simply configure the dimensions and geometry of the duct cross-section and see the volume flow displayed on the measuring instrument straight away
  3. You will even find it easy to carry out measurements in particularly large ducts. This is because the extendable telescope on the hot wire and vane probe (Ø 16 mm) with universal handle can be further extended using the telescope extension – enabling you to attain a total length of 2 metres
  4. Carry out measurements at air/ceiling outlets effortlessly and without using a ladder. Fit the vane probe (Ø 100 mm) with the extendable telescope with 90° angle and, if necessary, with the telescope extension (both can be ordered separately)
  5. Use the vane probes in conjunction with the testovent measurement funnels and flow straighteners to test incoming / outgoing air at plate outlets, ventilation grilles and swirl outlets
  6. Practical Bluetooth interface: use the air velocity probes to measure without having to deal with any bothersome cables, operate the measuring instrument by pressing the button on the handle of the probe, e.g. start or stop a timed mean calculation
  7. Use the practical magnets to securely attach the multifunction measuring instrument to metal surfaces (e.g. ventilation ducts) 

Long-term monitoring of indoor air quality 

  1. The right probe for your requirements: probes for CO2, CO, air temperature and humidity are available as variants with Bluetooth or with fixed cable
  2. Easy to use: enter the measurement period and interval in the menu for long-term measurement and track it over the course of the day
  3. Internal memory for up to 7500 measurement protocols

Turbulence measurement in accordance with EN ISO 7730 / ASHRAE 55 

  1. Attain a high level of accuracy, even at low air velocities, with a turbulence probe
  2. Automatic calculation of draught risk and degree of turbulence in accordance with EN ISO 7730/ASHRAE 55
  3. For convenient measurements at varying heights, we recommend using our measuring tripod for comfort level measurement. This makes it very easy to position turbulence probes in compliance with the standards 

Range of probes for cleanrooms and laboratories 

  1. Fume cupboard probe for high-precision air velocity measurement on fume cupboards
  2. Thanks to the low start-up speed of 0.1 m/s, the high-precision vane probe (Ø 100 mm) is ideal for laminar flow measurements in cleanrooms. Available as a variant with Bluetooth or with fixed cable
  3. High-precision temperature/humidity probe (0636 9771 or 0636 9772) with an accuracy of ±(0.6% RH + 0.7 % of m.v.) in the range 0 to 90% RH for measuring the humidity in cleanrooms
Temperature - NTC
Measuring range -40 to +150 °C
Resolution 0.1 °C
Accuracy ±0.4 °C (-40 to -25.1 °C) ±0.3 °C (-25 to +74.9 °C) ±0.4 °C (+75 to +99.9 °C) ±0.5 % of mv (Remaining Range)
Temperature - TC Type K (NiCr-Ni)
Measuring range -200 to +1370 °C
Resolution 0.1 °C
Accuracy ±(0.3 °C + 0.3 % of mv)
General technical data
Connectable probes 1 x digital probe with cable or 1 x Temperature NTC TUC, 1 x digital Bluetooth probe or testo Smart Probe, 1 x Temperature TC Type K
Battery type 3 AA mignon 1.5 V
Battery life 12 h (typically vane measurement)
Interface Bluetooth®; USB

Delivery Scope

Testo 440 air velocity & IAQ measuring instrument, incl. 3x AA batteries, USB cable and calibration protocol (0560 4402), CO2 probe with Bluetooth®, including temperature and humidity sensor (consisting of CO2 probe head and Bluetooth® handle), 4x AA batteries, table stand and calibration protocol (0632 1551), Combi-case for testo 440 and multiple probes (0516 4401)

CO2 kit with Bluetooth - testo 440 CO2 Kit
Model No: testo 440 CO2 Kit Part No: 0563 4405

Precise, reliable measurement of all air velocity and IAQ parameters with just one measuring instrument: the multifunction measuring instrument features intuitive operation with clearly structured measurement menus. Adjusting air conditioning and ventilation systems, monitoring air quality or carrying out comfort level measurements – thanks to versatile options for combining with high-quality, digital probes, you are ideally equipped to carry out your measuring task (please order probes separately) For assessing indoor air quality: use the probe (with the compatible measuring instrument) to measure CO₂ concentration, humidity and air temperature. The readings are transmitted directly to your measuring instrument via Bluetooth, making your measurements particularly convenient

  1. Intuitive: clearly structured measurement menus for volume flow, degree of turbulence, cooling/heating output, mould detection and long-term measurement, such as CO₂
  2. Wireless: Bluetooth® probes for extra convenience when measuring and less cable clutter in the measuring case (please order probes separately)
  3. Intuitive: clearly structured measurement menu for long-term measurement and parallel determination of CO₂ concentration, humidity and air temperature in indoor areas
  4. Precise: calculation of wet bulb temperature, dew point and absolute humidity


Testo 440 air velocity and IAQ measuring instrument in combination with high-quality probes to measure and store all air velocity and IAQ parameters (please order probes separately). Up to 3 probes can be connected simultaneously: a Bluetooth probe, a wired probe and a temperature probe with type K thermocouple connector. Automatic probe detection and clearly structured measurement menus guarantee simple operation and will make your day-to-day work easier.

Measure in just a few clicks with the testo 440 multifunction measuring instrument

Carry out your measurements quickly and easily: the air velocity and IAQ measuring instrument automatically detects each connected probe. This means that there is no need for you to manually reset the parameters when changing probes. Clearly structured measurement menus for measuring the volume flow in ducts/at outlets, funnel measurement, measuring the degree of turbulence, determining the cooling/heating output, mould detection and long-term measurement provide you with optimum support during your day-to-day work.

Wireless and space-saving: more applications, less equipment

Endlessly versatile: a universal handle can be connected to all probe heads – so you can master more applications using less equipment and save space.

The Bluetooth handle makes it more convenient to carry out your measurement and guarantees less cable clutter in the case. It makes it possible to carry out measurements without any bothersome cable connection and it transfers readings up to a distance of 20 m. Or as a practical alternative, use the cable handle to connect testo probe heads. This is an advantage if Bluetooth signals are not permitted.

Practical measurement data management

The multifunction measuring instrument stores up to a max. 7500 measurement protocols, which can be read via a USB port and further processed as a CSV file on your computer (e.g. with Excel). With the testo BLUETOOTH/IRDA printer (please order separately), you have the option of producing a report printout of the measurement data directly on site.

Intelligent calibration concept for maximum precision

You can rely on accurate measurement results when using our digital probes, because the measuring instrument makes measurement uncertainty a thing of the past. You only need to send the probes in for calibration. The multifunction measuring instrument can therefore remain in continuous use.

Advantages of measuring with the testo 440 air velocity and IAQ measuring instrument

Long-term monitoring of indoor air quality 

  1. The right probe for your requirements: probes for CO2, CO, air temperature and humidity are available as variants with Bluetooth or with fixed cable
  2. Easy to use: enter the measurement period and interval in the menu for long-term measurement and track it over the course of the day
  3. Internal memory for up to 7500 measurement protocols

Use the probe with the compatible testo multifunction measuring instrument (please order separately) to determine CO2 concentration, air humidity and air temperature. Wet bulb temperature, dew point and absolute humidity are calculated at the same time.

CO2 probe with Bluetooth including temperature and humidity sensor – features

Use the probe to check the indoor climate, for example in offices, production areas or storage facilities. To ensure accurate measurement results, air density compensation is carried out via the integrated absolute pressure measurement. The readings of the CO2 probe are transmitted to your measuring instrument via Bluetooth, up to a distance of 20 m.

Particularly useful: store individual readings directly in the measuring instrument by pressing the button on the probe. The clearly structured measurement menu for long-term measurement enables the measuring instrument to be operated intuitively. Reading trends are reliably recorded thanks to the convenient input of measurement time and measuring cycle. You can use these trends to evaluate changes in the indoor air quality.

Wireless and space-saving: more applications, less equipment

Endlessly versatile: a universal handle can be connected to all probe heads – so you can master more applications using less equipment and save space. The Bluetooth handle makes it more convenient to carry out your measurement and guarantees less cable clutter in the case.

Or order the cable handle to connect testo probe heads. This is an advantage if Bluetooth signals are not permitted. If the sensors (CO2, humidity, temperature) need to be replaced in the distant future, you can change the probe head.

Intelligent calibration concept

You will get exceptionally accurate measurement results with the digital probe, because the measuring instrument makes measurement uncertainty a thing of the past. You only need to send the probe head in for calibration – so the measuring instrument remains in continuous use.

Areas of application for the CO2 probe with Bluetooth

Use the CO2 probe including temperature and humidity sensor to check the indoor climate (indoor air quality), e.g. in offices, production areas or storage facilities.

The CO2 concentration is a primary indicator of indoor air quality. Poor air quality due to excessive CO2 concentration results in tiredness and lack of concentration, and can even cause illnesses. The CO2 concentration should therefore not normally exceed 1,000 ppm

Temperature - NTC
Measuring range 0 to +50 °C
Resolution 0.1 °C
Accuracy ±0.5 °C
Humidity - Capacitive
Measuring range 5 to 95 %RH
Resolution 0.1 %RH
Accuracy ±3 %RH (10 to 35 %RH) ±2 %RH (35 to 65 %RH) ±3 %RH (65 to 90 %RH) ±5 %RH (Remaining Range) ±0.06 %RH/K (0 to +50 °C)
Absolute Pressure
Measuring range +700 to +1100 hPa
Resolution 0.1 hPa
Accuracy ±3.0 hPa
Ambient CO₂
Measuring range 0 to 10000 ppm
Resolution 1 ppm
Accuracy ±(50 ppm + 3 % of mv) (0 to 5000 ppm) ±(100 ppm + 5 % of mv) (5001 to 10000 ppm)
General Technical Data For Probe
Length probe shaft 130 mm
Probe head diameter 30 mm
Battery type 4 x type AA batteries
Battery life 21,5 h
Data transfer Bluetooth
General Technical Data For Instrument
Connectable probes 1 x digital probe with cable or 1 x Temperature NTC TUC, 1 x digital Bluetooth probe or testo Smart Probe, 1 x Temperature TC Type K
Battery type 3 AA mignon 1.5 V
Battery life 12 h (typically vane measurement)
Interface Bluetooth®; USB
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