Grille Face Velocity Calculator
Face velocity and noise expectation for a supply/return grille at your airflow.
Noise rises ~18 dB per doubling of face velocity. Return grilles run even slower (≤ 2 m/s) because they're usually closer to ears.
Formula
Grille Face Velocity Calculator is a free grille velocity for HVAC designers, technicians and energy auditors — instant, accurate and 100% client-side, with the governing formula and reference shown next to the result so the number can be defended, not just quoted.
About Grille Face Velocity Calculator
Face velocity and noise expectation for a supply/return grille at your airflow. The calculation implements V = Q / (W×H×free-area) (ASHRAE — air distribution; manufacturer NC tables). Noise rises ~18 dB per doubling of face velocity. Return grilles run even slower (≤ 2 m/s) because they're usually closer to ears.
How to use Grille Face Velocity Calculator
- 1Enter Airflow through grille in L/s.
- 2Enter Grille width in mm.
- 3Enter Grille height in mm.
- 4Enter Free area in %.
- 5Read Face velocity instantly — no submit button needed.
- 6Need US units? Flip the SI/Imperial toggle and every field converts.
Why use Grille Face Velocity Calculator?
- ✓Implements the standard formula — V = Q / (W×H×free-area)
- ✓Reference cited on-page: ASHRAE — air distribution; manufacturer NC tables
- ✓One-click SI ⇄ Imperial toggle — values convert in place, physics stays in SI
- ✓Built-in engineering verdict flags out-of-range results instantly
- ✓Runs entirely in your browser — nothing uploaded, free forever
Frequently asked questions
What formula does the Grille Face Velocity Calculator use?+
It computes V = Q / (W×H×free-area), per ASHRAE — air distribution; manufacturer NC tables. The formula is displayed under the result.
What should I keep in mind when using this calculator?+
Noise rises ~18 dB per doubling of face velocity. Return grilles run even slower (≤ 2 m/s) because they're usually closer to ears.
Is this based on ASHRAE methods?+
The calculations follow the standard ASHRAE/ISHRAE formulations cited under the result, simplified where industry practice does the same. For permit-grade design, confirm with the full code procedure.
Is the Grille Face Velocity Calculator free to use?+
Yes — completely free, no sign-up, no limits. It runs client-side in your browser, so inputs stay private and results are instant even on slow connections.
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