Testo 420 Replacement Hood (1200 x 1200 mm)

Maximize your measurement range with the large-format Testo 420 replacement hood. Sized at 1200 x 1200 mm, this hood is designed specifically to capture air volume from large square air diffusers and grilles that exceed standard hood dimensions. Like all Testo 420 hoods, it features an integrated flow straightener that conditions turbulent air to deliver highly reliable, high-precision results in challenging ventilation systems.

Your Advantages

• Large Coverage Area: The 1200 x 1200 mm footprint is ideal for balancing high-capacity ceiling diffusers and large square ventilation grilles.
• Integrated Flow Straightener: Corrects turbulent inflow at large outlets, ensuring consistent accuracy even when the air distribution is uneven.
• Perfect Compatibility: Designed for an easy, secure snap-on fit with your existing Testo 420 measurement base.
• High-Durability Build: Manufactured from robust materials that withstand the physical stresses of field usage in commercial and industrial sites.

What It's For & Who It's For

Applications (What It's For)

This oversized hood is essential for commissioning high-volume air supply and exhaust terminals in warehouses, manufacturing plants, large commercial lobbies, and auditoriums. It enables rapid, one-person balancing of large-format diffusers that would otherwise require complex and time-consuming traverse measurements.

Who It's For

Ideal for professional commissioning engineers, commercial TAB (Testing, Adjusting, and Balancing) technicians, and facilities maintenance crews who need to handle a wide variety of terminal sizes with a single, highly accurate Testo 420 measurement system.

Tradie Pro Tip: Measuring large diffusers can be tricky because the air velocity is often uneven across the face of the grille. The integrated flow straightener is a massive time-saver here—it physically "levels out" the air before it reaches the sensor array, giving you a steady, reliable average reading the first time without having to perform multiple re-takes.

Delivery Scope

1 x Replacement hood for Testo 420 (1200 x 1200 mm), including a carrying bag (Product no. 0554 4204).

Technical Data