About the Ventilation & Airflow Calculators
Ventilation and airflow calculators help HVAC engineers determine airflow and outdoor air loads and evaluate fan performance. This section includes tools for calculating CFM from air changes per hour, finding the heating and cooling loads of outdoor air at a location, mixing two airstreams, applying the fan affinity laws, setting VFD frequency, computing fan energy index values for code compliance, and estimating the payback of an energy recovery ventilator. These calculators are used during system design to ensure that ventilation rates meet ASHRAE 62.1 and local code requirements while keeping fan energy and outdoor air loads in check. They are equally useful during commissioning and balancing when measured airflows need to be compared against design values. Each tool applies standard industry methods so results are directly comparable to equipment ratings and engineering specifications.