The professional software for glass & slat manufacturers

Professional calculation

Ug-Value, g-Value, Reflection, Absorption, Transmission, gtot-Value, SHGC-Value



for the calculation of photometric, solar and thermal parameters

Powerful functionality

with declaration of performance and CE marking


WINSLT® is the software solution for calculating photometric, solar and thermal characteristics of glazing in combination with solar shading. In WINSLT® own spectral datasets for coatings, glasses and sun protection can be imported and used. The climatic boundary conditions are freely selectable. Furthermore, the structure can consist of any number of glass panes and a lamella module is available as an add-on. After your calculation, the determined performance data for the respective product variants can simply be transferred to the declaration of performance and printed out.


  • Extensive database with various products from international glass and sun shading manufacturers
  • Import of own spectral data
  • Boundary conditions according to EN 52022-3 or freely definable
  • Calculations in accordance with US standard ISO 15099/ASHRAE
  • Calculation of any pane structure
  • Display of the temperature curve across the cross-section
  • Calculation of reflection, transmission and absorption
  • Creation of a declaration of performance and CE marking for any glass structures in many language versions

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  • Certified by independent testing institutes
  • Results are internationally recognized
  • Extremely user-friendly in operation
  • Reliable partner for long-term customer satisfaction
  • Market-ready solutions even before the relevant laws and standards are passed, along with ongoing updates - our solutions are always up to date

Normen in WINSLT®

Vacuum glass


Any structure can be created in a short time and installed in accordance with the standards:

  • EN ISO 673 ->Ugvalue
  • EN 410 -> g-value, reflection, absorption, transmission
  • EN ISO 52022-3 ->gtot value
  • ISO 15099 / ASHRAE -> Ugvalue, SHGC value, reflection, absorption, transmission

can be calculated. The ift-Rosenheim-certified software also generates a declaration of performance and CE labelling for the glazing.

Vacuum glass is increasingly being used due to its lighter construction combined with high insulation values – especially in the renovation of old buildings and in the field of listed buildings. The new WINSLT add-on takes this into account. For the first time, it is possible to carry out an exact, fully automatic calculation of vacuum glazing based on existing ISO/FDIS standards.


Creation of any blind slats (width, spacing, inclination, position of the sun) from any slat material.

Declaration of performance/CE labelling



On 1 July 2013, the Construction Products Directive was bindingly replaced by the new Construction Products Regulation. Due to its legal form, the Construction Products Regulation applies equally in all member states. With its introduction, the CE marking was also standardised throughout the EU. Previously applicable national regulations no longer apply. The CE marking is therefore also mandatory in all member states.

    The declaration of performance replaces the old declaration of conformity. The key difference here is that the declaration of performance must be created not only for certain product types, but for each individual product, which results in increased effort for manufacturers. The creation of a declaration of performance is integrated in WINSLT®. Once the calculation has been carried out in WINSLT®, the corresponding declaration of performance can be printed. The technical values from the calculation are transferred to the declaration of performance.

Extracting spectral data of LSG films from spectral data of entire LSG structures and extracting spectral data of coatings from the spectral data of coated glasses. The extracted data can then be combined with other glasses as measured.

Calculation of the radiative and thermal characteristics according to ISO 15099 with the specifications of ASHRAE. The ISO 15099 standard applicable in North America for calculating the thermal behaviour of windows, doors and solar shading devices specifies two ways of calculating a characteristic value in some cases.

    For this reason, the professional association of all companies in the heating, cooling, ventilation and air conditioning industry in the USA, also known as ASHRAE, specifies which path is to be taken. The calculation basis from the standard with the ASHRAE specifications, some of which also include the NFRC standards, are implemented in the software algorithm.
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Further variants & functions


  • Save local calculations from SommerGlobal in the cloud
  • Retrieve calculations from the cloud regardless of location
  • Load and edit items anytime and anywhere
  • View proofs as mobile documents
  • Manual storage by the user
  • Encrypted data

Test our demo version!

Test our demo version!

Our customers say

„Interpane Glasgesellschaft mbH has been an enthusiastic customer of Sommer Informatik GmbH for many years. The calculation with WINSLT® also worked quickly and effectively for us after a short training period, which is why we can only recommend this tool.“

Interpane Glasgesellschaft mbH

Interpane Glas Industrie AG is a German flat glass manufacturer based in Lauenförde. The company manufactures glazing products at ten locations in Germany, Austria and France.

Contact: Steffen Schäfer –

„WINSLT® is a powerful and very important tool for us, which professionally supports the user in carrying out the calculations.“

Ingenieurbüro Bauwerk

The engineering office has been active since 1998 and offers services in the field of building physics and window technology.

Contact: Dipl.-Ing. (FH) Roland Steinert –

Explanation of terms


Vacuum Glass

Vacuum glass is increasingly used due to its lighter construction combined with high insulation values – especially in old building renovations and in the field of monument protection.
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Creation of any louver slats (width, spacing, tilt, sun position) from any louver material.
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Calculation of the radiophysical and thermotechnical characteristics according to ISO 15099 with the requirements of ASHRAE.
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Extracting spectral data from laminated glass (VSG) films from spectral data of entire laminated glass assemblies and extracting spectral data from coatings from the spectral data of coated glasses.
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Declaration of Performance/CE Marking

In WINSLT®, the creation of a declaration of performance is integrated. After performing the calculation in WINSLT®, the corresponding declaration of performance can be printed.
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