Testo 405i Wireless Thermal Anemometer – Bluetooth, 0…30 m/s Air Velocity, Volume Flow and Temperature, 400 mm Telescope (0560 1405)

Testo 405i (product code 0560 1405), used with a smartphone or tablet, is a wireless thermal (hot-wire) anemometer. It measures air velocity, volume flow and air temperature at AC grilles, in ventilation ducts and indoors; values are transferred via Bluetooth to the free Testo Smart App app. 0 … 30 m/s measuring range and a telescopic probe extending to 400 mm let it easily reach measuring points inside the duct.

Air Velocity, Volume Flow and Temperature Measurement at Grilles and in Ducts

For volume flow measurement, the shape (round or rectangular) and size of the duct cross-section are entered in the app; the Testo 405i automatically calculates the volume flow (m³/h) from the measured air velocity. The app presents live values, the measurement trend and the logging function on one screen; the measurement protocol is sent directly as a PDF or Excel file.

The Testo 405i is used to check the discharge velocity of AC indoor units and the grille volume flow, to commission ventilation systems and to assess indoor air movement. When used together with the Testo 605i thermohygrometer, the app can also calculate the system's cooling capacity and heating output.

Technical Specifications (Official Testo Data)

• Brand / Model: Testo 405i · product code 0560 1405
• Air Velocity (hot wire): 0 … 30 m/s · resolution 0.01 m/s
• Air Velocity Accuracy: ±(0.1 m/s + 5% of reading) 0 … 2 m/s · ±(0.3 m/s + 5% of reading) 2 … 15 m/s
• Temperature (NTC): −20 … +60 °C · accuracy ±0.5 °C · resolution 0.1 °C
• Probe: telescopic, max. 400 mm length · shaft diameter 12 mm · tip diameter 9 mm
• Data Transfer: Bluetooth® · Testo Smart App (iOS 13.0 / Android 8.0 or later, Bluetooth 4.2)
• Power Supply: 3 × AAA batteries · battery life 15 hours
• Operating / Storage Temperature: −20 … +50 °C / −20 … +60 °C
• Dimensions / Weight: 200 × 30 × 41 mm · 119.6 g
• Body: plastic · black / orange

Scope of Delivery

• Testo 405i wireless thermal anemometer, extendable telescope (400 mm)
• Batteries
• Test protocol

Technician Tips

• Mind the sensor orientation: hold the sensor window at the probe tip perpendicular to the air flow; a probe held at an angle under-reads the velocity.
• Measure at several points in the duct: velocity is not uniform across the duct cross-section; for volume flow, measure at several points in a grid across the section and take the average, and do not measure immediately after elbows and dampers.
• Enter the duct size correctly: volume flow is calculated from the entered cross-sectional area; for grille measurements use the free (effective) area of the grille.
• Protect the hot-wire sensor: retract the telescope after measuring and do not touch the sensor tip; if the sensor gets dirty in dusty and oily environments, the measurement drifts.
• Plan battery life: the heated-wire sensor consumes power and battery life is about 15 hours; keep spare batteries for long commissioning jobs.

Technical document: Testo 405i datasheet (PDF, English)