News
The Heat Loss app has been updated, adding a function has been added to insert rooms from an image file with a schedule.
13.06.2026
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A version of the HVAC Calculator has been created for mobile browsers on Android and iOS.
09.01.2026
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All online applications have been updated and now have a dark theme.
04.01.2026
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Heat loss calculation is the fundamental calculation for heating design.

It is possible to start selecting a boiler, heat pump, radiators, hydraulic calculation only after determination of the heat loss.

With the help of this tool you will be able to perform the calculation of the heat load of the rooms and building fast and easy.
Calculation methods

Calculation is performed according to the standards:

  • EN 12831-1:2017 "Method for calculation of the design heat load".
  • ISO 6946-2017 "Thermal resistance and thermal transmittance".
  • ISO 10456 "Building materials and products".
  • ASHRAE Fundamentals. Building envelope. "Heat, air, and moisture control in building assemblies".
A lot of calculations
  • Thermotechnical calculation of the envelopes.
  • Calculation of the heat loss caused by the envelopes and thermal bridges.
  • Calculation of the heat loss caused by the infiltration through the gaps in the envelopes and by the ventilation.
  • Calculation of the heat loss caused by the adjacent unheated room.
  • Calculation of the heat loss considering the temperature fluctuations throughout the height of the room.
  • Calculation of the radiators.
Interoperability with AutoCAD

Envelopes can be drawn in AutoCAD and imported in online application.

Importing from AutoCAD is a very efficient tool, it allows to import the envelopes, their dimensions, area, and positioning in online application automatically.

Drawing the envelopes is performed by a separate module for AutoCAD.
Unique and user-friendly tools
  • Copying the floors with all rooms and radiators.
  • Imporing the envelopes in the room from another room.
  • Multi-editing of several rooms simultaneously.
  • Pasting the explication of all rooms.
  • Editable database of climatology, materials, products, temperature.
  • Download and upload of the calculation from a cloud or file.
  • It is possible to work on any PC, no need to install the application.
  • Always current released version of the application, no need to update.
Detailed reports
  • Heat loss calculation report in Excel.
  • Report of thermotechnical calculation of the envelopes in Excel.
  • Report of the calculation of the radiators in Excel.
  • Diagram of the heat loss throughout the project or room.
  • Chart of the temperatures in the room.
Video review

Just watch video and start working: