Home > Testo >

Testo 420 Flow Hood Kit
Testo 420 Flow Hood
Testo 420 Flow Hood
Alternative Views:

Price: $2,544.00
Sale Price: $2,289.60

Request a Formal Quote  

Availability: Subject to availability
Product Code: 0563-4200


Testo 420 Flow Hood Kit

Complies with strict California Energy Commission standards!

The Testo 420 Flow Hood offers the performance of a German-engineered balometer combined with a highly accurate removable manometer. With airflow (CFM or CMH), temperature, and humidity at the push of a button, the Testo 420 makes an excellent choice for any HVAC testing, adjusting, and balancing application. The Bluetooth equipped manometer can wirelessly send test data to your Apple or Android smart device in real time for monitoring, graphing, and data capture. The manometer can also be removed from the Testo 420 flow hood, to become its own standalone test instrument for measuring pressures or checking airflow in ductwork with a pitot tube. Also available (separately) is a telescoping stand with wheels that can be used to test volumes at ceiling registers without ever needing a ladder. Even while the balometer is high above, you will have all data in the palm of your hand thanks to the free Testo 420 app.

  • Measures flow rate, temperature, relative humidity, and differential pressure
  • Wireless capabilities via Bluetooth and Testo 420 Smartphone App
  • Detachable manometer for pitot velocity measurements or static pressure testing
  • 2 GB of internal memory

The Testo 420 calculates airflow through measuring pressure with a Wilson flow grid. Static and total pressures get averaged separately and then the difference is taken between the two average pressures to produce an velocity pressure reading. Equipped with a standard 2'x2' hood, the Testo 420 will fit a variety of grilles and registers. Accessory hoods are also available in additional sizes to fit larger registers, or to ensure greater accuracy on smaller openings. The Testo 420 comes equipped with a flow straightener to improve accuracy of turbulent air flow. Weighing just 6.2 pounds, the 420 is designed to be light and rugged for easy transport and quicker set up.

The Testo 420 is equipped with Bluetooth capabilities which allow for the use of a smartphone or tablet as a remote control and data display. The Testo 420 app is free and provides all of the information that is on the original 420 instrument. The Testo 420 app also allows for on-site reports to be produced in either pdf or Excel format. Through the app allows you can add photos and comments to the report. Once you are finished with your report, you can send it from the app directly to the client.

Volume Flow Temperature Relative Humidity Differential Pressure
Measuring Range 50 to 2120 CFM -4 to 158 °F
(-20 to +70 °C)
0 to 100 %RH 0 to 5" H2O
(0 to 120 Pa)
Accuracy ±3 % of m.v. ±0.9 °F (32 to 158 °F)
±0.5 °C (0 to +70 °C)
±1.8 %RH ±2 % of m.v.
Resolution .5 CFM 0.1 ° 0.1 %RH 0.001 Pa


  • Testo 420 with 2'x2' Hood
  • Lightweight Flow Hood Base with Bluetooth
  • USB Cable
  • Batteries
  • Soft Case with Telescoping Handle and Wheels


The Testo 420 Flow Hood carries a 2-year warranty.

Share your knowledge of this product. Be the first to write a review »

Browse for more products in the same category as this item:

Testo > Testo Air Flow
Air Flow