testo 420 Balometer (Airflow Hood) | 50–4000 m³/h, flow straightener, approx. 2.9 kg, detachable differential pressure meter, Bluetooth App

testo 420 Airflow Hood: Accurate Air Volume Even at Swirl Diffusers

Overview

The testo 420 airflow hood measures air volume at supply and return outlets of HVAC systems, for example in hospitals, office towers and commercial buildings. A built-in flow straightener evens out the turbulent flow from swirl diffusers into a nearly uniform airflow, reducing measurement error. The complete set weighs under 2.9 kg and has a tilting display and handle; the measuring instrument can be detached for use as a differential pressure meter and connects to a smartphone App via Bluetooth.

Key Specifications

• Air volume: 50–4000 m³/h; ±3% of reading + 12 m³/h at 85–3500 m³/h (22 °C, 1013 hPa); resolution 1 m³/h
• Differential pressure: −120–120 Pa, ±2% of reading + 0.5 Pa, resolution 0.001 Pa
• Temperature, humidity and barometric pressure: Temperature −20–60 °C ±0.5 °C (0–60 °C); humidity 0–100 %RH; barometric pressure 700–1100 hPa
• Display and data: 3.5-inch dot-matrix backlit display; 2 GB memory; Micro-USB, Bluetooth 4.0 (approx. 10 m)
• Power: AA batteries, approx. 40 h
• Weight and dimensions: 2900 g; 610 × 610 mm standard hood
• Included: Measuring instrument, 610 × 610 mm hood, 5 support rods, USB cable, batteries, transport trolley

Applications

• HVAC air balancing (TAB) and acceptance of air volume at supply and return outlets.

Specifications per the testo English website product page for the testo 420 airflow hood (0563 4200) (retrieved 2026-10-21).