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Testo 440 - humidity kit

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The Testo 440 is a practical kit for the measurement of temperature and humidity in a wide range of applications such as indoor air quality studies and in HVAC ductwork systems. The 440 handset is a multifunction measuring instrument which can be used with a number of different optional indoor air quality probes, and the wireless Bluetooth probe can be used to accurately measure temperature & humidity over the range of - 20 to + 70 °C / 5 to 90 % rh, as well as the calculation of dew point, wet bulb temperature and absolute humidity.

Product Features

  • Range of accessories
  • Calibration options
  • Document downloads
  • Instrument video
  • Instrument FAQs

Instrument product options

1. Select a model (1 available)

Model subtotal: £359.00
Total (excl VAT): £359.00
Continue to select accessories

2. Select accessories (44 available)

3. Select a calibration (3 available)



  • A compact hand-held measuring instrument with intuitive measurement menus and a wide selection of air velocity and IAQ probes (optional accesories)
  • Clearly structured measurement menus. 
  • Easy storage and evaluation of measurement data. Measurement data memory for up to 7500 measurement protocols, which can be read via a USB port and further processed as a CSV file on the computer (e.g. with Excel)
  • Practical magnets for easy attachment of the measuring instrument to metal surfaces (e.g. ducts)
  • Automatic detection of probes, e.g. humidity probe
  • Large, backlit colour display

Scope of standard supply

Testo 440 air velocity and IAQ measuring instrument, 3 x AA batteries, USB cable and manufacturers calibration protocol
Testo Bluetooth temperature and humidity probe, 4 x AA batteries and calibration protocol (0636 9731)
Basic case for testo 440 and 1 humidity probe


Probe part No.      0636 9731

Humidity sensor type      Capacitive

Humidity measuring range     0 to 100 % rh

Humidity accuracy     ± 2 % rh (5 to 90 % rh)

Humidity resolution     0.1 % rh

Temperature sensor type      NTC

Temperature measuring range     - 20 to + 70 °C

Temperature accuracy     ± 0.5 °C

Temperature resolution     0.1 °C



Testo 440 product range BSRIA data sheet

  • Technical Document
  • PDF file
  • 4 MB

Testo 440 user manual

  • Technical Document
  • PDF file
  • 3 MB

Testo air velocity and IAQ Bluetooth probe user manual

  • Technical Document
  • PDF file
  • 897 KB

Testo air velocity and IAQ probe user manual

  • Technical Document
  • PDF file
  • 356 KB

Demonstration video

Testo 440 product range overview



When using a wireless Bluetooth probe how far from away from the handset will the probe register a signal ?


Typically the probe will transmit distances up to 10 m (line of sight).


Can you connect two wireless Bluetooth probes to a 440 handset ?


Unfortunately no.  The handset is designed to work with a single wireless Bluetooth probe, a single wired probe and an additional Type K mini plug style thermocouple can additionally be fitted as well.

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