1. Learn how to get access to early-stage architectural models
  2. Learn how to modify the settings in Sefaira Systems so that the model will be interpreted correctly for your HVAC system analysis

Sefaira Systems allows HVAC designers to run analysis directly off early-stage architecture models, i.e. models that display the level of detail needed for analysis during conceptual or schematic design. You can read more about these models and their purpose here.

If you don’t have access to a SketchUp or Revit model to use for your analysis we can create one for you. Please contact support@sefaira.com if you need help creating a model. Modeling guidelines for creating an architectural model for Sefaira analysis can be found here.

This chapter focuses on the modifications you can make within the Sefaira Systems app to ensure that the model you uploaded is interpreted in the way you intend.

Sefaira Systems Model Interpretation Guidelines

  • While internal conditions can be set up by zone, we currently only support one HVAC system type per building
  • Envelope properties and internal conditions are set in the Sefaira Systems application interface. This means that this or any additional building information included directly in your Revit model will not be interpreted and used in your Sefaira analysis
  • Sefaira does not support the use of Revit spaces or Revit zones to define Sefaira zones. Only Revit rooms can be used to define Sefaira zones
  • One zone per room analysis in SketchUp is defined by any break in the floor plate, be it a line or intersecting interior wall. 

Setting Up a Project

First, you need to set the zoning strategy you are looking to use. There are three strategies of zoning available in Sefaira Systems:

  1. a single zone for the entire floor
  2. a core/perimeter zoned model
  3. one zone per room 

The images below show the different interfaces for each zoning strategy. For all three zoning strategies, the internal conditions can be set differently for each floor. For the core/perimeter and one zone/room strategies, internal conditions can also be set for each individual zone. Note that while you can specify internal conditions per zone, you can only use one system type for the entire building (i.e. not select system types per zone).

For SketchUp users only

Sefaira will interrupt any divisions of the floor plate in SketchUp as separate zones, whether those divides are just a basic line, or a single plane wall. If using a wall just be sure to tag as an interior wall for Sefaira


For Revit users only

Sefaira uses early-stage architectural models that are likely to not have a lot of detail. If you are using a Revit model that has Revit spaces or Revit zones defined, note that these will not be read by Sefaira’s analysis (only Revit rooms can be used to define Sefaira zones).

All conditioned square footage of your design needs to be defined as a room in Revit to be a zone in Sefaira analysis. These rooms CANNOT overlap, if they do, the analysis will not run. 

Building envelope properties like U values, SHGC values, wall thicknesses, etc. are set within the Sefaira Systems application to enable easy comparison of different options while using the same model. This means that BIM data from Revit models will not be used for the Sefaira analysis.


  • Sefaira uses early-stage architectural models for systems analysis
  • Revit and SketchUp models allow for one zone per room analysis 
  • Building properties must be set within the app interface, not within the model