Testo 420 Volume Flow Hood
The Testo 420 Volume Flow Hood is engineered for fast, accurate airflow balancing and HVAC commissioning across commercial, healthcare, and industrial environments. Designed specifically for larger ceiling diffusers and air vents, the Testo 420 simplifies volume flow measurement while helping technicians maintain compliance with indoor air quality and ventilation standards.
Built with portability and efficiency in mind, the lightweight 2.9 kg design makes the instrument easy to transport, position, and operate during long measurement sessions. The integrated flow straightener improves accuracy at swirl diffusers by minimizing turbulence-related measurement deviations, delivering more reliable airflow readings in demanding applications such as cleanrooms, hospitals, office spaces, and production facilities.
Accurate Airflow Measurement Made Simple
The Testo 420 is designed to measure:
- Volume flow
- Air velocity
- Differential pressure
- Temperature
- Relative humidity
With a measurement range from 50 to 4,000 m³/h, the instrument delivers precise airflow balancing for a wide range of HVAC systems.
The standard 610 x 610 mm hood is ideal for large air outlets, while optional hood sizes allow the unit to adapt to different diffuser dimensions and airflow applications.
Watch the Testo 420 Volume Flow Hood in Action
Lightweight Design for Easier Handling
Unlike many traditional balancing hoods, the Testo 420 has been developed with technician comfort in mind. Ergonomic side handles, quick-assembly tension rods, and a compact base unit allow for rapid setup and convenient operation on-site.
The detachable measuring instrument can be tilted or removed entirely for easier viewing, particularly when working overhead or in awkward ceiling locations.
For measurements at elevated ceiling diffusers, the optional tripod system extends reach up to approximately 4 metres while improving operator safety and stability during testing.
Smart App Connectivity and Wireless Reporting
Bluetooth connectivity allows the Testo 420 to integrate seamlessly with the free Testo Smart App, enabling technicians to monitor readings directly from a smartphone or tablet.
Using the app, users can:
- Start and stop measurements remotely
- View live airflow readings
- Save data instantly
- Create digital reports on-site
- Export results as PDF or CSV files
- Email reports directly to customers
The mobile app also acts as a second display, making overhead measurements safer and more convenient when the hood is mounted on a tripod.
Testo 420 Key Features:
- Designed for large ceiling diffusers and swirl outlets
- Integrated flow straightener for improved measurement accuracy
- Measures airflow, temperature, humidity, and pressure
- Airflow measurement range: 50 to 4,000 m³/h
- Lightweight construction at under 2.9 kg
- Fast hood assembly with tension rod system
- Bluetooth connectivity with Testo Smart App
- Removable display with illuminated screen
- USB data transfer and internal memory storage
- Optional tripod for high ceiling applications
- Compatible with additional hood sizes and accessories
What comes with the Testo 420 Flow Hood?
- Testo 420 Measuring Instrument
- 610 x 610 mm Flow Hood
- Measurement Base
- Tension Rods
- USB Cable
- Batteries
- Wheeled Transport Trolley / Soft Case
- Calibration Protocol
❓ Frequently Asked Questions (FAQ)
Q1: What is the Testo 420 used for?
A. The Testo 420 is used for measuring and balancing airflow in HVAC systems. It is commonly used in commercial buildings, hospitals, cleanrooms, offices, and industrial ventilation applications.
Q2: Can the Testo 420 measure swirl diffusers?
A. Yes. The integrated flow straightener is specifically designed to improve measurement accuracy at swirl outlets and ceiling diffusers.
Q3: Does the Testo 420 connect to a smartphone?
A. Yes. The instrument features Bluetooth connectivity and works with the free Testo Smart App for live readings, reporting, and remote operation.
Q4: What airflow range can the Testo 420 measure?
A. The Testo 420 can measure volume flow from 50 to 4,000 m³/h.
Q5: Is the Testo 420 suitable for high ceilings?
A. Yes. An optional tripod allows measurements to be taken safely at ceiling heights up to approximately 4 metres.
Q6: Can the measuring instrument be removed from the hood?
A. Yes. The display unit can be detached and used separately for duct measurements, differential pressure testing, and Pitot tube applications.