How to prepare IFC files in Revit / Archicad for Thermal calculations in InstalSystem 5 (for architects and BIM coordinators)

Product	InstalSystem 5
Type of article	TIP&TRICK
Source for translation	2025-08-18

Problem description

To ensure the accurate creation of the thermal model of a building and the recognition of automatic rooms, it is necessary to correctly interpret architectural elements from Revit / Archicad into native InstalSystem 5.5 elements. Therefore, a BIM model created in Revit / Archicad should be properly prepared for export.

Solution

Basic recommendations for optimizing the preparation of BIM models for the exporting to InstalSystem 5.5

• For best results, export only the relevant elements needed for Thermal calculations of building. Avoid exporting unnecessary architectural and structural details (furniture, elements protruding beyond the actual building structure, decorative architectural elements, grids, roof fittings) and external elements (roads, sidewalks, trees, walls) by setting the type to Not Exported / Export to IFC – No.
  Elements such as beams (IfcBeam) or ramps should be excluded unless they are integral to the thermal analysis;
• Export only elements that enclose space, such as walls (ifcWall), ceilings (ifcSlab), roofs (ifcRoof), windows (ifcWindow), and doors (ifcDoor). These elements must form a sealed geometry (the "closed box" principle) that will allow recognizing automatic rooms;
• Select export settings that will ensure a small file size, avoid overly detailed geometry or exporting unnecessary parameters;
• Models and their elements should be simplified as much as possible — combine multi-layered elements such as walls, slabs, and roofs if their layers form independent, contiguous elements;
• Ensure proper element mapping (mapping settings):

IFC element	InstalSystem 5.5 element
ifcWall / ifcWallStandardCase	Wall
ifcCurtainWall	Curtain Wall
ifcSlab	Slab
ifcRoof	Roof
ifcWindow / ifcDoor / ifcOpeningElement	Window / Door / Opening in wall
ifcSpace	Room (manual)

Export Storeys (IfcBuildingStorey)

• Storeys should be created and exported in accordance with the logic of InstalSystem 5.5: each Storey contains such elements as Slab, Wall and Roof (on the top Storey).
  For more information, see: BIM - Creating storeys based on data from IFC model;
• Avoid situations where Slab and Roof elements form separate Storey. Such export creates unnecessary, redundant Storey , which complicates the subsequent IFC (BIM) building data interpretation.
  

Export architectural elements

Export Wall (IfcWall)

• Agree on one type of wall as ifcWall (instead of ifcWall and ifcWallStandardCase);
• Avoid exporting walls that are not necessary for Thermal calculations of building (e.g. retaining walls, walls located outside the thermal contour of the building);
• Wall elements should be divided into Storeys: each Wall should start and end on the same Storey and should be aligned with the Storey elevations. There should be no gaps between the Wall and the storey Slab / Roof.