Program options - EnergyPlus

EnergyPlus tab of the Program options dialog


You can select the version of EnergyPlus to use in your simulations. This can be useful to target a specific DOE version you may wish to use or when a new version becomes available which might provide new functionality or address previous problems.


You should generally select the recommended DLL option as it is more tightly integrated within DesignBuilder and provides progress feedback.


DesignBuilder comes with 2 internal versions of EnergyPlus:



...or you can select an executable version of EnergyPlus supplied by DOE. If you are exporting IDF data for use outside DesignBuilder you should select the appropriate DOE version to avoid incompatibilities.


Note: the EnergyPlus version selected here is used for simulations within DesignBuilder but also as the target version when exporting IDF data for use outside DesignBuilder.


If you select an executable version (internal or DOE) there are four options available to control the way EnergyPlus is executed when simulating within DesignBuilder:



EnergyPlus export folder

When using a DOE EnergyPlus executable version you must also select the folder where the selected version is installed. You can scan the disk for DOE installations by clicking on the link in the Info help panel..


When you select any option other than the default DLL option, the necessary EnergyPlus files are downloaded seamlessly prior to the first simulation following the change.


Note: If you wish to install a different DLL version of EnergyPlus to that which is recommended, you must have administrative rights on the computer.


DesignBuilder are licensed distributors of EnergyPlus.   All versions of EnergyPlus supplied by DesignBuilder have been compiled by the DOE.

ESO Output

You can generate ESO output files containing Heating design, Cooling design and Simulation results. The files can be loaded later using the File > Load results file menu option, provided the model hasn't changed too much.




  1. The DesignBuilder model must still have same zones and surfaces it had at the time the simulation data was generated
  2. If you have modified these files and carried out further simulations in EnergyPlus you should find that the results will read in OK provided you haven't changed zone or surface names in the IDF data.
  3. You cannot read in ESO files generated from IDF data which was entered by hand (or by other software) because the zone and surface references will be different.
  4. Results must be loaded to the correct screen - you can't for example read Heating design results into the Simulation screen.
  5. Simulation only: the results to be read in must have been generated using the same simulation period and number of timesteps currently set in the Simulation options.


If you choose to Save ESO simulation output then you can also select options to Prompt for filename and Auto load ESO described below.

Prompt for filename

Tell DesignBuilder whether you wish to be prompted for a filename after each simulation.  If you choose not to be prompted then DesignBuilder will automatically generate output filenames based on the name of the dsb file, the calculation type, the calculation description and the date. It places the file in the EnergyPlus folder.  If you choose to be prompted the file can be stored anywhere on your computer system.

Auto load ESO

Check this option to automatically load the ESO results file after simulations. If you have been warned that there will be a lot of data and the program may crash on reading results you may wish to switch this option off and reload the results later. It is often possible to read in very large ESO files after DesignBuilder has restarted following a simulation and this can be a useful for avoiding a crash due to too much data. You may also wish to switch the option off to avoid waiting for the results to read in when carrying out parametric simulations.


This option only refers to Simulation results no Heating/Cooling Design results.

IDF Options

Display extra warnings

Requesting Display extra warnings causes the statement:




to be included in the IDF data. This option is for experienced EnergyPlus users who understand the significance of the extra warning messages generated.

IDF Formatting

The IDF data can be formatted using the options:



Options will be made available in future versions to ease reading of IDF data generated by DesignBuilder.