Ventilation rate is one of the key factors determining both Energy Use Intensity (EUI) and HVAC design capacities in a modern, well-insulated building. The Sefaira Architecture plug-in contains a property setting for ventilation rate in order to set up the analysis for more realistic results. Recommended values are included in our custom baselines.

For guidance, typical minimum ventilation rates are around 7.5-10 L/s.person, while high levels of air quality can be achieved with ventilation rates of around 15 L/s.person. [Ref: ASHRAE Technical FAQ, CIBSE Guide A]

Ventilation in EnergyPlus

In EnergyPlus the setting for ventilation rate is per person. A value between 7.5 and 15 L/s.person is recommended to maintain adequate CO2 levels inside the building and to correctly account for ventilation heat exchange with outside air. The ventilation rate is assumed to be constant, based on the specific occupant density of the selected building profile. By default we assume a mechanical ventilation heat recovery system to be in place with 50% efficiency.

As the ventilation rate here is specified per person, we need to factor in occupant density to achieve a representative area specific value. An example of this is shown in the recommended adjustments for projects in Denmark.