Accurate and convenient measurement in ducts with Testo measuring instruments

The easy way to optimum measurement results in all flow velocity ranges.

In order for air conditioning and ventilation systems to run smoothly and efficiently, the flow velocity in the ventilation duct must be regularly checked. Only when the flows in the duct correspond to the requirement are the room loads (heat, cold and substance load) reliably transported away – and the indoor air quality is right.

If the ventilation duct is accessible, duct measurement is then the best solution. This is because air flows are measured most accurately directly in the duct. However, it must be taken into account that the flows in the duct are usually non-homogenous and turbulent.


In order to obtain reliable results in spite of this, measurements should always be taken at several points over the duct cross-section. In these grid measurements, the mean flow velocity is calculated from the individual measurement values.

Ventilation measuring instruments from Testo support you in grid measurement just as reliably as in the automatic calculation of volume flow.

Which instrument suits your application depends on the flow velocity range you wish to measure.

Lower flow velocity range up to 5 m/s

Thermal anemometer testo 425 (0 to 20 m/s)

Our accuracy champion in the flow velocity range from 1 to 5 m/s. With fixed telescopic flow velocity probe up to 820 mm length for duct measurement.

Thermal anemometer testo 405i (0 to 30 m/s)

Work comfortably thanks to operation completely via testo Smart Probes App. Easy report creation and data dispatch by e-mail.

Thermal anemometer testo 405 (0 to 10 m/s)

Particularly accurate in the range between 0 and 2 m/s Equipped with 300 mm telescopic probe. Automatically calculates the volume flow.


Medium flow velocity range from 5 m/s

Vane anemometer testo 416 (0.6 to 40 m/s)

Our accuracy champion in the flow velocity range from 5 m/s. Telescope length up to 890.

Differential pressure measuring instrument testo 420 (-120 to +120 Pa)

Measures flow velocities up to 14 m/s in combination with a Pitot tube or a flow velocity matrix.


Medium to high flow velocity range from 40 to 100 m/s, as well as highly contaminated flows

Differential pressure measuring instrument testo 510 (-100 to +100 hPa)

Compact and with integrated display.

Differential pressure measuring instrument testo 510i (-150 to +150 hPa)

Controlled by your smartphone. Reports easily created and sent via testo Smart Probes App.


For more details please visit our website or contact us on bellow address:

Testo India Pvt. Ltd.
Plot No. 23, Sind Society, Baner Road, Aundh, Pune – 411007 Maharashtra, India

Phone: +91 20 6560 0203
Fax: +91 20 2585 0080