ALUMINUM PASSIVE HOUSE WINDOW SYSTEMS
The design of sustainable building envelopes demands more than just implementing the current energy standards. In view of the challenges of climate change and amended legal adjustments, windows will be required to match concepts such as passive house
In order to reach the Passive House Standard, sustainable aluminum window systems are necessary for energy-efficient building. Such systems combine the benefits of aluminum with maximum thermal insulation for design-oriented, sustainable architecture.
Traditionally Passive House performance windows have been manufactured out of more inert materials, such as wood, uPVC and pultruded fiberglass. While these materials yield a very high thermal performance, they lack some of the structural benefits of aluminum. The strength of aluminum profiles allows for larger window frames without the need for intrusive re-enforcement profiles.
Window Frame Materials
Aluminum Passive House certified windows combine the stability, longevity and design aesthetic that are required by the most astute clients and rigorous performance specification. Modern thermally broken aluminium windows, like Schüco AWS 90, are a long way from the old single pane aluminium windows that neither performed thermally, nor were structurally strong. Large polyamide thermal breaks combined with foam cavity infills allow the performance of these windows to reach the same levels as wood and fibreglass while maintaining the structural qualities of standard aluminium windows.
Vinyl windows make up about 2/3 of the current window market. While vinyl is the most budget-friendly option, it has some real challenges when it comes to strength, thermal expansion and are highly vulnerable to UV damage in sunny locations.
Wood windows have been used throughout the world and have the longest history of usage. They provide great thermal performance, but require a regular maintenance schedule of re-finishing and neglecting this schedule will result in the wood frame drawing in moisture, which eventually will lead to rot and full replacement of the windows.
Fibreglass windows are newer to the market. As a frame material, they have the highest thermal rating, and as such work well for Passive House requirements. The biggest drawback to fibreglass windows is it’s a requirement for structural re-enforcement profiles when window sizes are larger than a typical punch window i.e. window walls and curtain walls. The other challenge is when specifying windows into architecturally designed homes is their lack of clear and sharp lines. Due to the process of pultrusion, it is not possible to execute clear sharp profiles that are most often seen in aluminium window profiles and lend themselves to clean and modern design.