Global thermal insulation coefficient (G calculation)
A tool developed by the BIMTECH team to calculate the global thermal insulation coefficient (G), a required step in the Technical Documentation for the Building Permit (D.T.A.C.).
Global thermal insulation coefficient calculation
In the video below we present a tool developed by our team to automatically calculate the global thermal insulation coefficient (G calculation) directly from the Revit model — a required step when submitting the Technical Documentation to obtain the Building Permit (D.T.A.C.).
What is the G coefficient? The global thermal insulation coefficient characterises the heat loss of a residential building through its envelope (walls, floors, windows, roof) relative to the heated volume. It is a mandatory requirement in the technical documentation for permitting residential construction in Romania.
Instead of manual calculation in spreadsheets, our tool automatically extracts the areas, volumes and thermal properties of the elements directly from the BIM model (Revit), reducing errors and working time.
Required resources
Revit template — BITa 2020 simplified
The Revit template prepared for the G calculation, with the required parameters and families.
Download →Dynamo script — G calculation
The Dynamo script that extracts data from the model and computes the coefficient.
Download →Engipedia Layers Manager
Autodesk add-in for managing material layers — recommended.
Autodesk App Store →Dynamo Packages
Install from Dynamo → Package Manager: Clockwork for Dynamo 2.x, Springs, SteamNodes.
How it works
Start from the template
Open the model using the simplified BIT architecture 2020 template, with the thermal parameters ready.
Define the layers
Configure the materials and thermal properties of the envelope (with Engipedia Layers Manager).
Run the Dynamo script
The script reads the areas and volumes from the model and computes the heat loss.
Get the G coefficient
The result is ready for D.T.A.C., with no manual calculations and reduced errors.
Need help with the tool?
BIMTECH / buildingSMART Romania members have access to resources, templates and community support for openBIM workflows.