ASHRAE Standard 183 Building Load Calculations Using SketchUp / OpenStudio

October 8th, 2019

In this YouTube video we discuss the steps needed to create building geometry using SketchUp with OpenStudio Plugin. Building heating and cooling loads are then calculated according to ASHRAE Standard 183 using the U.S. Department of Energy, EnergyPlus simulation engine via OpenStudio.


All software used for these calculations (SketchUp, OpenStudio, and EnergyPlus) are open-source and free to download.

Open Studio Modeling Steps:


  1. Create new OSM from Wizard

  2. Window->Preferences->General Set Auto-Save time step

  3. Extensions->Open Studio->Preferences Set Unit System to IP

  4. Window->Model Info->Geo-Location->Add Location

  5. Window->Preferences->OpenGL-> check: Use maximum texture size. You can uncheck this later if it bogs the model down.

  6. Extensions->User Scripts->Template Generators->Space Type Construction Set Wizard and add additional space types. Uncheck create const set. Uncheck set building defaults.

  7. Draw scaling line to exact dimensions

  8. File->Import and locate project site plan or floor plan. Drop into model and scale to the scaling line. Do not rotate to true north until you are finished modeling.

  9. Trace lines over floor plan using sketchup drawing tools. Select floor plan, Right click, and use hide/unhide as necessary. (Window->Preferences->Shortcuts to modify keyboard shortcuts)

  10. Once floor plan is completed, select all the floor plan line elements and use Create Spaces from Diagram button

  11. Double click the spaces to edit their height, draw additional features or plenums, and add windows and doors.

  12. Extensions->OpenStudio User Scripts->Alter or Add Model Elements->Intersect Space Geometry

  13. Click the Surfacematching button -> Match Entire Model

  14. Select a space and click Set Attributes for Selected Spaces button. Assign space types to all spaces. At this time you may open the OpenStudio Inspector and rename the spaces according to your preference.

  15. Extensions->OpenStudio User Scripts->Alter or Add Model Elements->Add New Thermal Zone for Spaces with No Thermal Zone

  16. Select spaces one-by-one and rename them per the project floor plans.

  17. Extensions->OpenStudio User Scripts->Alter or Add Model Elements->Rename Thermal Zones Based on Space Names

  18. Select spaces in groups by type. Click Set Attributes for Selected Spaces button. Fill in info for space type and thermostat type. You may also use this dalog to combine thermal zones into one.

  19. Extensions->OpenStudio User Scripts->Alter or Add Model Elements->Remove Unused Thermal Zones

  20. Select specific windows and then Extensions->OpenStudio User Scripts->Alter or Add Model Elements->Add Overhangs by Projection Factor

  21. For vertical or custom shading, click New Shading Surface Group button.

  22. Rotate model to account for true north.

  23. If Geo-Location has been lost, reinsert it for reference to existing buildings.

  24. Create adjacent shading (buildings, trees, etc) by clicking New Shading Surface Group and use Geo-Location as reference. You may have to trace Geo-Location image prior to editing the shading group, then use those tracings as reference.

  25. Click Window->Default Tray->Shadows to see and simulate the shadows. Delete any unnecessary surfaces from the shading group to minimize calculation time.

  26. Open Open Studio Inspector and Purge Unused Objects from OpenStudio Resources to reduce calculation time. Select "OS:Building" and type in the project name.

  27. Click Launch OpenStudio button.

  28. Preferences->Units->English (I-P)

  29. Select the appropriate weather file and design day files.

  30. Select Schedules tab->Schedules. Add on/off schedule for exhaust fans.

  31. Select Thermal Zones tab->HVAC Systems. Review to ensure all spaces have thermostat schedules applied. Add exhaust fans to zones.

  32. Select Thermal Zones tab->Cooling Sizing Parameters. Change all Zone Cooling Supply Air Temperatures to 55°F. Change air distribution effectiveness if applicable.

  33. Do the same thing for Heating Sizing Parameters.

  34. Select Measures tab and select Reporting drop-down. Drag the BCL Open Studio Results measure to the Reporting Measures.

  35. Run Simulation

  36. Go to the model directory and open the html file using your web browser. Print to pdf file for record/reference.

To see E+ results in IP units: Select Measures tab. Click Find Measure on BCL button. Use the search box and type: IP Units. Select and download the "Set Output Table to IP Units". Close the BCL. Drag the downloaded e+ report measure to the e+ measures.

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