Insulating bars for aluminum windows - polyamide, low-lambda polyamide, ABS or Noryl?

By Bogdan Grebenyuk, Product Manager at Thermevo
on Nov 29, 2017
Different types of plastic could be used for a high-precision insulating profile. The difference between them is not only in their thermal conductivity level but also in their material properties and production costs.
Meaning of insulating bars for facade systems

Aluminum windows without thermal separation no longer correspond to the state of the art. In order to achieve an energy efficiency of aluminum windows and doors, it is necessary to form a correct insulating zone in the profile of the façade system. High-precision insulation profiles in modern windows are located between the individual profile parts to ensure thermal separation and, at the same time, a stable connection between the inner and outer shell of the frame. However, the requirements for the thermal insulation properties of the building exterior continue to grow with each amendment of the Energy Saving Ordinance. Therefore, it makes sense not only to calculate the U-value but also to perform a U(f) value optimization during the development of aluminum profiles. Modern software solutions make it possible to achieve ideal values.

Influence of material and geometry on U(f) value optimization

Which U-values for window and door systems with thermal separation is influenced by different factors. A low level of thermal conductivity of the insulating zone within the frame plays an essential role here. This can be further reduced by different measures. First of all, they include the widening of the insulating strip as well as the spacing between the shells and the foaming of the hollow chambers of the insulating strips for thermal insulation. Use of plastics with particularly low U-values also provides a high optimization potential for improvement of the U-value for windows and doors of aluminum. The research and development of new materials are therefore very important in the aluminum window industry. Already Albert Einstein recognized:

Today's progress goes so fast that, while someone claims a thing to be completely impracticable, he gets interrupted by another who has already implemented it.

Insulation of polyamide and other plastics in comparison

To produce high-quality insulating strips you need materials that have a very low thermal conductivity, but at the same time have good material properties in terms of longevity and stability, that's why only plastics are suitable for this purpose today. Currently, insulating strips made of polyamide or acrylonitrile-butadiene-styrene copolymer, abbreviated as ABS, are used for the construction of energy-efficient façade systems. There are also relatively new on the market insulating strips made of so-called low-lambda polyamide, which has a significantly lower thermal conductivity than regular insulating strips made of polyamide. Both plastics, however, are hygroscopic. In case of contact with moisture, they may swell and shrink, which is considered quite an unfavorable behavior. Upon the other hand, insulating profiles made of ABS still have lower U values than those made of polyamide, but a powder coating, which is a common method for the production of aluminum windows, is not available for them. Noryl as a material for insulation products has a top performance in terms of insulation. However, profiles made from this material are relatively expensive to manufacture.

Software comparison of plastics for insulating bars

Many factors have to be taken into consideration to find out which insulation strip is most suitable for facade systems. In addition to the thermal conductivity level, the building physical properties, and the production cost play a major role here. This aspect makes the selection of a suitable plastic for aluminum windows and doors quite a complicated task. Therefore, it makes sense to compare different variants using an appropriate software. Here we proudly introduce Flixo Cloud, an online tool that offers manufacturers and planners not only the possibility to calculate the U-value of insulating profiles or entire facade systems - if required, the program provides the quotation price for the production of individual insulating profiles. Both the efficiency as well as the energy efficiency of an insulating profile can thus be clearly determined. This enables a strategic approach in the development and production of modern façade systems.Just try it out and compare prices by choosing different materials for your window profile using Flixo Cloud software.
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