Building Energy Software Tools
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Calculates temperature distributions, heat flows and (optionally) vapor diffusion flows in building structures - particularly those with thermal heat bridges. AnTherm (Analysis of Thermal behavior of Building Construction Heat Bridges) is designed for the technically qualified designer by providing thorough and reliable evaluation of thermal performance in accordance with current European standards (EN ISO).

It directly calculates characteristic indicators for the construction, such as linear (or point) thermal transmittance or the matrix of thermal coupling coefficients (i.e. boundary conditions independent results).

AnTherm facilitates generation of geometrical models through a graphic input display of building structures, as well as by providing very fast, fully automated generation and precise solution of the underlying numerical model. AnTherm allows the user to control the precision of numerical solutions through parameters.

The thermal performance of assemblies with overall dimensions of up to approximately 100 meters and details as small as 1/10 mm can be simulated with AnTherm. Limitations to the scope of evaluation depend on the capabilities of the PC (available RAM, number and speed of processors).

Expertise Required: 

None special required. Basic understanding of building physics, thermal transfer and computer use are sufficient. In depth knowledge of heat transfer mechanisms and standard regulations is helpful to evaluate and solve complex problems.


Building physics consultants, energy performance consultants, designers, engineers, architects, moisture analysis experts, insurance analysts, building product developers, researchers, teachers and students.


Data is entered with a graphical user interface, instant numerical and graphical (2d and 3d) feedback supported by detailed construction reports.

Geometry (2-dimensional, 3-dimensional sliced or 3-dimensional) entered by rectangular areas assigned to materials, power sources or spaces.
Oblique and rounded shapes can be entered and will be converted to rectangular areas.
Model draft can be imported from selectively preprocessed DXF, Waebru, Kobru86 and Heat2/3 files.
Thermal (and optionally vapor diffusion) conductance properties of materials, transfer coefficient of surface elements (standard properties available by selection from the material database included).
Boundary conditions: air temperatures, (optionally) power densities and relative air humidity (primary results - like the conductance matrix, linear and point transmittance, U-values at adiabatic boundaries - can be obtained without providing any boundary conditions).


Results from AnTherm include:

Generally applicable results in the form of g-values (temperature weighting factors) and conductance matrices (thermal coupling coefficients) conformant to the European Standards, including the required information on calculation precision.

Specific results, applicable to particular air temperature conditions in spaces thermally coupled by the building components analyzed, in the form of surface temperature minima and maxima as well as respective dewpoints (maximum non-condensing air humidity).

Interactive two- and three dimensional graphic plots and prints of isotherms, surface and interior temperature or heat flux distribution as well as streamlines of the heat flow (not limited to 2-dim. models only, but also in 3D). Vapor diffusion pressures, flux and flow visualizations are available as an extended option.

Fully automatic execution of calculation with AnTherm is given even in the event of poorly conditioned calculation cases. The maximum quantity of balanceable equations is nearly unlimited (several ten millions), thus making the thorough analysis of large, three-dimensional models feasible. Complex cases are given, for example, by components or spaces in contact with ground, entire spatial envelopes or groups of spaces, or detailed modeling of complicated assemblies like window frame and installation details, steel reinforced structures, etc.

Textual Output (standardized reports):

Project description, materials used, detailed construction report including U-values at adiabatic boundaries.
Conductance matrix and distribution factors (thermal coupling coefficients).
Standardized information on calculation precision (close-up error).
Linear thermal transmittance (psi) for two dimensional, two space cases.
All data for deriving point thermal transmittance (chi) for three dimensional cases.
Minimum and maximum temperatures for each space surface and location, g-Values, fRsi temperature factors.
Maximum relative air humidity of surface condensation at coldest point of each space.
Temperatures at arbitrary chosen interior or surface points (probe points).
Export to file formats like PDF, RTF, XLS.

Graphical output (three dimensional graphs and advanced visualization techniques) include:
Model view colored by material conductance (optional explosion view).
Colored surface (with isolines) and orthogonal slices (with isolines) of temperature, condensing humidity, heat flux and optionally partial or saturated vapor pressure or vapor diffusion flux.
Heat flow streamline(s) colored by any other scalar value (e.g. temperature, heat flux, etc.).
Vapor diffusion flow streamline(s) (option).
Isosurface of any of the above scalar values within components interior (valuable for identification of three dimensional thermal heat or vapor diffusion bridges).
Surface temperature graphs.
Combinations of above through opacity/transparency and visibility options.
Axes, labels, annotations, probing of values, various coloring tables.
Export to pictures formats such as JPG, PNG, and BMP as well as to scene formats such as VRML, OOGL, and OIV.
Graphics can be transferred via clipboard to other picture or word processing application.


Easy to use, short learning curve.
Fast and fully automated generation of computational discrete model and computation (optionally, users can take full parametric control of that).
Immediate and precise results conformant to standards, standardized result reports.
Advanced interactive visualization techniques significantly speeding up the process of analysis.
Direct calculation of characteristic indicators for the construction, such as linear (or point) thermal transmittance or the matrix of thermal coupling coefficients (i.e. boundary conditions independent results).
Very fast recalculation of result under new, different boundary conditions without the need to run the full simulation from scratch (based on the concept of "basic solutions" independent of boundary conditions).
Precise calculation of even very large models of millions of equations (and the eightfold number of “super-fine-grid” nodes during evaluation) easily possible on moderately equipped typical PCs. Equation size limits result only on technical limits of hardware used.
Fully validated conforming to EN ISO 10211:2007: AnTherm has been qualified as a "Class A" tool for two- and three-dimensional, stationary high precision method.
Fully validated conforming to EN ISO 10077:2003: AnTherm has been qualified as standard method for calculation of heat flow through frames of windows, doors and shutters.
Extensive documentation and tutorials (English and German) including nearly full theoretical background information. Includes context sensitive help available directly within the application.
English and German user interface which can easily be adopted in the future for additional languages.
Maximally utilizes currently available personal computer technology, including multiprocessor/multicore environments.

Major Capabilities: 
Whole-building Energy Simulation
Parametrics & Optimization
Ratings and Certificates
Reduced for Non-Commercial/Academic Use
Help and Support: 
Subscription Email Support
Last Software Update: 
19 May 2016
Last Entry Update: 
17 August 2016
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