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Testo 440 - hot wire kit

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The Testo 440 hot wire kit is designed to measure air velocity, volume flow and air temperature in ventilation ducts. The 440 handset is a multifunction measuring instrument which can be used with a number of different optional indoor air quality probes, and the fixed cable 9 mm diameter hot wire probe can be used to accurately measure air velocity from 0 to 30 m/s over a temperature range between - 20 to + 70 °C using a robust sensor and automatic absolute pressure compensation.  The telescope probe handle can be extended to 0.85 m, and comes with scaling marks to make it it easy to measure in ventilation ducts.

Product Features

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

Instrument product options

1. Select a model (1 available)

Model subtotal: £399.00
Total (excl VAT): £399.00
Continue to select accessories

2. Select accessories (44 available)

3. Select a calibration (4 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: the volume flow is precisely calculated using the size and geometry of the duct cross-section. Timed and multi-point mean calculation, average volume flow, current reading and min./max. values are displayed
  • 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. hot wire 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
  • Hot wire probe (Ø 9 mm) with fixed cable (length 1.7 m) including temperature sensor, with telescope (can be extended to 0.85 m) and calibration protocol (0635 1032)
  • Basic case for testo 440 and 1 hot wire probe


Probe part No.      0635 1032

Velocity probe type      Hot wire  

Velocity measuring range     0 to 30 m/s

Velocity accuracy     ± 0.03 m/s + 4 % of mv, 0 to 20 m/s

                                   ± 0.5 m/s + 5 % of mv, 20.01 to 30 m/s

Velocity resolution     0.01 m/s

Temperature probe 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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