Question-and-Answer Resource for the Building Energy Modeling Community
Get s tarted with the Help page
Ask Your Question

Revision history [back]

The I/O reference guide for the output variable Zone Radiant HVAC Heating Rate [W] states:

This field reports the heating input rate to the low temperature radiant system in Watts. This is the heat source to the surface that is defined as the radiant system. The heating rate is determined by the zone conditions and the control scheme defined in the user input.

So yes. If you are only looking at inlet&outlet temperatures and the Zone Radiant HVAC Heating Rate, you should also at least look at the Mass flow rate in the system as well to gain some rough interpretation of what is going on.

More info: Source code / Engineering reference:

The source code that sets the Output variable in question is located here in

HeatPower maps to totalRadSysPower which is the sum, for each surface of state.dataHeatBalFanSys->QRadSysSource which is calculated in ConstantFlowRadiantSystemData::calculateLowTemperatureRadiantSystemComponents and described in the Engineering Reference in chapter Radiant System Models