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Hygric and Thermal Simulation

Roll-out of new release (V1.10)

The new version of HTflux V1.10 is currently being rolled-out. This means HTflux will suggest to update upon the next program launch. We do recommend to proceed the update as soon as possible. The new version of HTflux offers many new features, improvements as well as bug-fixes.

Here is an overview of the most important new features:

New dynamic model for air cavities (ISO 6946)

In addition to the models already in place, a new cavity model according to ISO 6946 has been integrated. The new model does also consider the direction of the heat-flux relative to the direction of gravity. Therefore it can consider the convection more precisely (e.g. resulting in increased heat transport on upward heat-flux).  (Note: it will be necessary to check or set the direction of your model correctly).
Link: Modelling air cavities

Freezing soil

A new feature allows the simulation of freezing soil considering latency heat while freezing, as well as the change in thermal conductivity and heat capacity of the frozen ground. Using this feature it is possible to improve the accuracy of thermal simulations of building-components with ground contact.
An application of this new feature can be found here: Slab edge on freezing soil.

Ψg – thermal bridging calculation tool for ground contact models

A new comfortable tool allows you to perform ISO calculations of floor slabs or basements easily.
A short tutorial explaining various methods can be found here: Ground contact calculations.

Extension of the table containing standard values for surface resistances

New standard values of ISO 1264 have been integrated into the template table. These default values should be used for simulations of components containing surface embedded heating or cooling elements.
Overview of the new values: Surface resistances for the simulation of surface embedded heating or cooling systems

Heat transfer of pipe-flows

A new versatile feature allows the simulation of heat-transfers of pipe-flows very easily. Based on an (automatically processed) series of fluid-dynamical calculations HTflux will calculate a characteristic surface resistance value for the heat-transfer of the fluid. This can be used to simulate all kinds of pipe-flow applications (ventilation pipes, water pipes, heating pipes,…).  On top of this HTflux will also output a number of useful fluid-dynamical key-figures (Reynolds-number,  Nusselt-number, pressure-drop, pipe resistance,…).
Links: Heat transfer of pipe flows-calculation tool, Chimney application, Floor heating application

New demo projects

New and interesting demo-projects have been added to the installer. The new examples will be installed automatically with the update.

Export condensation profile as graphic

A new features allows the export and import of the condensation profile in graphical format (png).  This provides an easy way to freely add or remove condensation spots in the simulation. This way the evaporation and dry-out potential of buildings components can be studied easily.


The new feature enables you to export your model into CAD applications using the DXF exchange format. The layers will automatically be named and arranged according to the active material-assignments of the objects.

New certificate

The new installer as well as the application itself is digitally signed with a new certificate accepted by Microsoft. This should eliminate any security warnings during the download and installation process and guarantees the integrity and authorship of the software.

Czech translation available

With the kind support of Vítězslav Calta a Czech translation of the software is available now.

Optimized performance for Windows 10

HTflux has been recompiled on a new platform to provide increased performance on systems running the Windows 10 operating system.

Enhanced time-series export of dynamic simulations

The current selection of time-series is now saved with the project or project template for further exports. The export format has been improved for import into Excel sheets.

Fixed temperature feature for materials

Dynamic simulations contain a new feature that allows the definition of a constant temperature for certain materials and certain time periods (similar to boundary conditions). The features now allows and easy and seemless simulation of switching on and off processes.
Link: Dynamic simulation of underfloor heating systems

Multiple monitor bug fixed

A bug that caused the display of certain dialogs and controls only on the main screen has been resolved.

Further bug fixes and improvements of the user-interface