Testo 425 Hot-Wire Anemometer 0.01 to 30 m/s Bluetooth with App Connectivity

Measuring air velocity and temperature in ducts, vents, and HVAC systems often requires bulky equipment or manual logging. The Testo 425 hot-wire anemometer solves this by combining a telescopic probe, precise sensors, and Bluetooth connectivity to the Testo Smart App, enabling convenient measurement, data logging, and reporting from your mobile device.

Who is it for

HVAC technicians, facility managers, and building inspectors who need reliable airflow and temperature measurements for system balancing, commissioning, and troubleshooting.

Main features

• Hot-wire sensor measures air velocity from 0.01 to 30 m/s with high accuracy.
• Telescopic probe extends up to 820 mm for hard-to-reach measurement points.
• Bluetooth 4.2 connectivity pairs with the Testo Smart App for remote display, data logging, and report generation.
• Integrated temperature measurement from -20 to +70 °C.
• Backlit LCD for clear readings even in dim environments.
• Calculates volume flow and timed/multi-point mean values.
• Powered by 3 AA batteries with up to 120 hours of operation.

Specifications

• Air velocity range: 0.01 to 30 m/s
• Air velocity accuracy: ±(0.03 m/s + 5% of mv) (0.01 to 1.00 m/s); ±(0.05 m/s + 5% of mv) (1.01 to 30 m/s)
• Air velocity resolution: 0.01 m/s
• Temperature range: -20 to +70 °C
• Temperature accuracy: ±0.5 °C
• Temperature resolution: 0.1 °C
• Probe type: Hot-wire, telescopic, up to 820 mm
• Connectivity: Bluetooth 4.2
• Display: Backlit LCD
• Power supply: 3 x AA batteries
• Battery life: 120 hours
• Operating temperature: -20 to +50 °C
• Storage temperature: -20 to +50 °C
• Protection class: IP40

Tips

For accurate readings, allow the hot-wire sensor to acclimatize to the ambient temperature before measuring. Use the timed mean function to average fluctuating airflows over a set period.