VAV Box Minimum and Maximum Airflow
Max = zone sensible / (1.08 x supply deltaT), min = max(ASHRAE 62.1 ventilation, turndown x max). 12,000 Btu/hr, 20 F, 100 CFM vent, 0.30 turndown -> 556 max, 167 min (turndown governs); a denser zone at 250 CFM vent is driven to 250 by fresh air. The box range and ventilation calc govern.
Formula and source
cfm_max = load / (1.08 x supply_dt); cfm_min = max(ventilation_cfm, turndown x cfm_max).
The VAV box maximum and minimum airflow from the zone load and the ASHRAE 62.1 ventilation minimum, by name.
Audience
This tile is built for hvac and the adjacent professions in the HVAC group. The interactive calculator runs entirely in your browser. No account, no fee, no advertising, no tracking.
Related tools
Posture
Rough Logic answers the math question the working professional asks on the job. The site is a calm, fast, ad-free, account-free, ever-free reference. It does not interpret code. It does not replace the licensed professional. It does not store your inputs. The Authority Having Jurisdiction governs all installations and inspections.