Testo 405 Thermal Anemometer (Air Velocity Meter) – 0…10 m/s, Volume Flow and Temperature, 300 mm Telescopic Probe, Rotating Display (0560 4053)

Testo 405 (product code 0560 4053) is a thermal (hot-wire) anemometer with a display that measures air velocity, volume flow and air temperature in ventilation ducts, air conditioner vents and indoors. Values are read directly from the device's rotatable LCD display; no phone or app is needed for measurement. With 0 … 10 m/s air velocity, volume flow calculation up to 99,990 m³/h and a telescopic probe that extends to 300 mm, it is especially suitable for in-duct measurements.

Telescopic Probe with Duct Holder and Rotating Display

The telescopic probe is adjustable between 150 … 300 mm; the supplied duct holder fixes the probe in the measuring hole. Because the lower part of the probe shaft can be rotated by 90°, the display remains readable while the probe is in the duct. When not measuring, the protective cap at the probe tip is closed with a short twist to protect the flow sensor; the arrow on the cap shows the flow direction for which the device is calibrated.

For volume flow, the duct cross-section area (m²) is entered when the device is switched on; the Testo 405 calculates the volume flow in m³/h from the measured air velocity. One button switches between the air velocity, temperature and volume flow displays. Because it measures precisely at low air velocities, it is also used to detect drafts around windows and doors and for indoor comfort checks.

For those who want Bluetooth connectivity, a measuring range up to 30 m/s and reporting via an app, the wireless Testo 405i model of the same family is available.

Technical Specifications (Official Testo Information)

• Brand / Model: Testo 405 thermal anemometer · product code 0560 4053
• Air Velocity (thermal): 0 … 5 m/s (−20 … 0 °C) · 0 … 10 m/s (0 … +50 °C) · resolution 0.01 m/s
• Air Velocity Accuracy: ±(0.1 m/s + 5% of measured value) 0 … 2 m/s · ±(0.3 m/s + 5% of measured value) remaining range
• Volume Flow: 0 … 99,990 m³/h (by entering the duct cross-section area)
• Temperature (NTC): −20 … +50 °C · accuracy ±0.5 °C · resolution 0.1 °C
• Probe: telescopic, 150 … 300 mm · shaft diameter 16 mm · tip diameter 12 mm
• Display: LCD, rotatable
• Power Supply: 3 × AAA batteries · battery life approx. 20 hours (approx. 750 measurements of 2 minutes) · auto power-off after approx. 5 minutes
• Operating / Storage Temperature: 0 … +50 °C / −20 … +70 °C
• Dimensions / Weight: 490 × 37 × 36 mm · 115 g (including batteries)

Scope of Delivery

• Testo 405 thermal anemometer, telescopic probe
• Duct holder
• Clip
• Batteries

Technician Tips

• Hold it according to the flow direction: position the probe so that the arrow on the protective cap points in the same direction as the airflow; a probe held backward or at an angle shows a lower velocity.
• Enter the cross-section area in m²: a 400 × 300 mm rectangular duct is 0.12 m², a Ø250 mm round duct is approx. 0.049 m²; a wrong area makes the volume flow wrong by the same proportion.
• Measure at several points in the duct: the velocity is not the same at every point of the duct cross-section; for volume flow, measure the cross-section at several points and take the average, and do not measure immediately after elbows and dampers.
• Mind the range in cold air: in air below 0 °C the measuring range is limited to 5 m/s; take this into account for outdoor air intakes and cold ducts.
• Protect the sensor: close the protective cap after measuring, do not touch the sensor and do not leave the device in direct sunlight.

Technical document: Testo 405 thermal anemometer product brochure (PDF, Turkish)