Testo 420 - Volume flow hood

Volume flow hood, with body, 610 x 610 mm flow hood, 5 x tension rods, USB cable, batteries and trolley
Part number: 0563 4200
Manufacturer: Testo
£2,159.00 (ex VAT)


The new volume flow hood testo 420 is the light, precise and convenient solution for regulating volume flows at larger air intakes and outlets. At swirl outlets in particular, the flow straightener significantly reduces the usual measurement errors. This allows users to fulfil hygienic Indoor Air Quality guidelines and stipulations in ventilation and air conditioning systems quickly and precisely, e.g. in industry, office rooms or in cleanrooms.



Handling is especially easy with a uniquely low weight of less than 2.9 kg and ergonomic handles. The measuring instrument can be tilted and removed for more comfortable readout of the measurement values. In addition to this, mobile devices can be used via Bluetooth App integration as a second display and remote control. This makes the use of a tripod for high ceilings especially secure and comfortable. Users can furthermore use the App to finalise and send the measurement report directly on site. The testo 420 App is completely free and is available for iOS from the App Store and Android via Google Play.



  • Less than 2.9 kg weight
  • Flow straightener for more precise measurement at swirl outlets
  • Removable and tiltable measuring instrument with a large display
  • App integration via Bluetooth for fast and easy monitoring and reporting on site


Despite it's size, the testo 420 is very light and easy to handle


Sensor types

  Volume flow NTC Capacitive humidity sensor Differential pressure
Measuring range 40 to 4000 m³/h -20 to +70 °C 0 to 100 %RH 0 to 120 Pa
Accuracy ±1 digit ±3 % of m.v. +12 m³/h at +22 °C,
1013 hPa (85 to 3500 m³/h)
±0.5 °C (0 to +70 °C)
±0.8 °C (-20 to 0 °C)
±1.8 %RH +3 % of m.v. at +25 °C
(5 to 80 %RH)
±2 % of m.v. +0.05 Pa
Resolution 1 m³/h 0.1 °C 0.1 %RH 0.001 Pa


General technical data

Operating temperature -5 to +60 °C
Storage temperature -20 to +60 °C
Weight 2.9 kg
Standard hood 610 x 610 mm
Battery type Alkali manganese, mignon, Type AA
Battery life 30 hrs
Display Dot matrix with illumination
Memory 2 GB internal
Interface Micro USB
Warranty 2 years