Developing of a cost-efficient, energy-optimized window, built of wood and ecological insulating materials

Development of a sustainable windowconstruction using solar energy and ecogical materials.

Short Description




Part A - motivation, aims, methode:

Freisinger is a pioneer in the fields of doors, windows and facades for low-energy- and passive-houses. A distinctive feature is that Freisinger only uses natural materials for its products. The project has the target to find a 100 % ecological window-construction near to the passive-standard but much cheaper than a typical passive house window.

To optimize the thermal quality of the window, modern computer simulated calculations with finite-element-method will be realized.

The realized pilot-project "Samerberger Passivhaus" is a small one-family-house in passive-house-quality. The project result, the new "ZwoaHolz" window, has to be successful under the conditions of this one-family-house. At the 3. passive-house-conference in Bregenz experts discussed if there is a possibility to realize a one-family-house in passive-house-standard.

All passive-house-windows which are available at the market have a cost-intensive continuous insulating layer. In this project a different solution shall be found to avoid the cost-intensive continuous insulating layer. With computer simulated calculations with the finite-element-method, the most efficient areas in the window-frame shall be found to place small insulating areas instead of a continuous insulating layer.

At the moment a "normal" window-frame at the market have an heat-insulating-value of approximately Uf = 1,6 W/m²K and the passive-house-window-frames have an heat-insulating-value of approximately Uf = 0,7 W/m²K. Other constructions are hardly available. A value of Uw = 0,85 W/m²K, certified by "Passivhaus-Institut Darmstadt", shall be reached in order to realize new market possibilities in the field of energy-efficient new buildings and in the growing market of building-reconstructions.

A scientific base of the project is the "Protokollband 14: Arbeitskreis kostengünstiger Passivhäuser" and the report "HIWIN: Hochwärmedämmende Fenstersysteme, Untersuchung und Optimierung im eingebauten Zustand".

Part B - results:

The aimed project results have been reached. The certificate "Geprüfter Fensteranschluss", certified from passivhouse-institute in Darmstadt, is reached and exists. The success of the product on the market is better than expected. There have already been built 647 window-units of this construction type. This is approximately a quarter of the whole production-quantity in 2004.

The new product is built with the renewable wooden exterior-layer, which is patented by Freisinger. It was possible to put in all construction details from the existing patent to the new product.

It was possible to show the technical usability in the pilot-project "Samerberger Passivhaus" (one-family-house) and in a pilot-project of a multi-floor-apartment-building.

The next steps are the preparation of a heat-bridge-catalogue especially for the new "Zwoa2Holz"-window. First connection-situations have already been calculated. At the end the architect or the consumer shall find all details, all technical values, drawings, isothermal-lines and Psi-values on the website of Freisinger.

Planners will also have the possibility to calculate their Psi-values especially for their build-in-situation, very fast and free of charge. In this way additional cost-saving is possible.

The results of this R&D-project have been presented at the passive-house-congress in Krems (2004), at the 1. Passive-House-Meeting in South-Tyrol (2004) and on the "Passive House Ireland 2004" in Dublin.

In addition to this project it is planned to show different build-in-situations with the "Zwoa2Holz"-window at the 9. Passive-House-conference 2005 in Ludwigshafen in order to sensitize the need of an integral planning process.

After the end of the project Freisinger made an investment for changing the production- and building-situation in order to optimize the production conditions. This was another direct consequence of the successful results of this project.

Project Partners

Project manager: Dipl.Ing. (FH) Franz Freundorfer
IZF Innovationszentrum Fensterbau
Lohbachstraße 3
D-83080 Oberaudorf
Tel: (0049) 0170 34 66 0 99
Fax.: (0049) 040/3603826642


Dipl.Ing. (FH) Paulus Freisinger
Freisinger Fensterbau
Wildbichlerstraße 1 A-6341 Ebbs