EP results - Openstudio vs EnergyPlus component


For the same model, I’ve noticed differences between the .csv files generated by Energyplus component and the one generated by the Export to Openstudio component. I know it recommended to use Export to OS component, but sometime I need to use EP component for HB generates. I’ve tried to open the .csv and the IDF files, but could not find the issue.

Does any one know why the results are different?

EPvsOS.gh (612.6 KB)

@MohammedAlshayeb ,

A difference of 0.7% is smaller than a rounding error in terms of energy modeling and you would be overconfident in the accuracy of your results if you are worrying about this small difference.

If it helps explain what is happening, I can tell you that the only differences between the OpenStudio IDF and the EnergyPlus IDF are that the OpenStudio models a “real” ideal air loads system that is being sized to heat/cool the zone why the E+ component uses an ideal air template (so the OpenStudio one is slightly more realistic). With this said, both types of ideal air systems aren’t “real” HVAC systems since, as their name denotes, they are “ideal” systems that cannot actually exist in the real world. So, if you truly need something accurate, you should model a real HVAC system using the OpenStudio component and a HVAC template other than ideal air loads.

I hope this helps,


Thank you @chris. Yes, the difference is not significant but I was wondering. Thanks again !