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Hygric and Thermal Simulation


A paper of the Graz University of Technology dealing with concrete core activation is now available on the HTflux website. The article summarizes the main findings of the study carried out in the scope of the diploma thesis of Wolfgang Gappmaier. (more…)


The English translation of this great book by Hermann Kaufmann, Stefan Krötsch and Stefan Winter and many others is now available. I’m glad I had the opportunity to contribute a small chapter on summertime overheating to this great book. (more…)

UPDATE: Please find a newer page on this topic here.

Finally I can provide the thermal-mass Excel-calculation tool, which I have promised for quite some time…  I hope this tool will help to get rid of all the simplified approaches suggested in the national standards and still used too much. (more…)

Great interest and feedback on my presentation on “Summertime-Overheating in Buildings” held at the Holzhaustage in Bad Ischl. Using videos of dynamic thermal simulations created with HTflux it was easy to vividly illustrate the function of thermal mass.
I’ll be happy to share my views on this issue of growing importance elsewhere… 😉

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. (more…)


Everything you always wanted to know about your heating system…

In the following example two underfloor heating systems are simulated using the dynamic simulation feature of HTflux. Based on these transient simulations we will reveal the differences in the dynamic behavior between these two systems. (more…)

Freezing Soil Frost Heave Foundation

Appropriate for the season and the current cold weather conditions in Europe a new feature has been integrated in to HTflux. The new feature will be available in next version of HTflux (1.10) which will be rolled out soon. It 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. (more…)

Schöck HTflux Isokorb Kooperation

Thermal bridge optimization raised to the power of two! We proudly announce the cooperation with the world’s leading supplier of innovative thermal insulation solutions. In cooperation with Schöck Bauteile Ges.m.b.H, Vienna we were able to create a comfortable tool that allows users to easily process individual thermal simulations with ISOKORB® elements. (more…)


The following practical example demonstrates how HTflux can be used to efficiently analyze even complex details with little effort. The details shows the connection of a PVC window to a timber frame wall. A comprehensive assessment regarding the condensation risk of the detail can easily be performed using HTflux unique Glaser-2d function. (more…)

research report summer overheating

A research report on summer overheating is available now. The report summarizes the findings of a research project carried out within the scope of the building science lab of the Graz University of Technology. (more…)

HTflux Simulation Software

Due to a migration of our servers you might be unavailable to launch HTflux and to reach our website for several hours. The migration will take place at local night-time, starting at August 30th 20:00 CEST (18:00 UTC) and can take until August, 31th 8:00 CEST (6:00 UTC). We apologize for any inconvenience you might experience.

HTflux Simulation Software

The new beta version V1.00 of HTflux is out now. We highly recommend updating as the new version offers new features and small bug fixes. Due to organisational issues the beta phase will be extended. All licences were automatically extended until May.


HTflux Simulation Software

The new beta version V0.99 of HTflux is out now. It will be the last beta version before to official release, coming very soon. We highly recommend updating as the new version offers new features and small bug fixes.


Thanks to the excellent cooperation and professional skills of Mr. Cristián Muñoz the entire user-interface of HTflux is now also available in a high quality Spanish translation. Mr. Cristián Muñoz is architect as well as expert for Energy Efficiency and Sustainability at the CITEC, University of Bio-Bio, Chile.

We would like to inform you about the release of the new beta version V0.98 of HTflux. We highly recommend the update as the new version offers new features and small bug fixes. (more…)

window-frame heating

The following example demonstrates the possibilities of using the HTflux heat source feature. The task was to optimize a window frame heating for an indoor pool area. The aim of the heating cable design was firstly to avoid condensation at the floor section of the sliding door frame and secondly to prevent damage of the frame caused by freezing. (more…)

Transient Thermal Simulation with HTflux

HTflux latest feature enables you to process transient thermal simulations. Using the built-in video encoder you can easily create high-resolution videos of the temperature as well as of the heat-flux view or you can export the time-resolved data of the measuring tools (such as temperatures, total heat flux,…) for further analysis. This enables you to calculate dynamic thermal characteristics of your assembly (e.g. periodic thermal transmittance, time shifts, decrement factor,…)


PV Erdkabel Simulation

The video shows a simulation of underground cable array exposed to a cyclic daily clear sky photovoltaic load (maximum PV-load). The boundary conditions have been chosen to largely comply with the relevant standard VDE 0276 (20°C surface temperature, adiabatic boundaries below surface). (more…)


HTflux is highly suitable for designing, optimizing or assessing timber constructions.  The design of timber constructions can be very demanding from a hydrothermal point of view. HTflux will give you the information you need for this task.  It provides precious information for passive house planners, but it’s ease of use make it suitable for the whole construction industry. As an example we present a pitched roof junction detail of a timber frame construction. (more…)