I have observed significantly faster transient heating/cooling behavior in EnergyPlus models, compared to data from real buildings, and identified the thermal inertia of the ducts as the most likely cause.
Is there a way to add thermal mass to the connections from the heating/cooling plant to the rooms in EnergyPlus?
There seems to be no such property here: https://bigladdersoftware.com/epx/docs/9-1/input-output-reference/group-airflow-network.html#airflownetworkdistributioncomponentduct