When reading about Passive House you will come across the name Prof. Dr. Wolfgang Feist and his Passive House Institute in Germany. Dr. Feist and his research institute are setting standards for building houses with an annual energy consumption of less than 10 kWh/m2 per year. These are houses that need very little heating in winter or cooling in summer. This is made possible by superior isolation of floors, walls, and the roof as well as technology to recycle energy that is already in the house. This requires also superior windows and doors, which when closed, keep the temperate in the house at a comfortable level without much additional energy use.
The VEKA Window System offers solutions that are fully compliant with these advanced standards. With the proper glazing and the excellent VEKA frames you can reach U values below 0.7 W/m2K. However, a passive house with such objectives requires a highly sophisticated ventilation system to ensure that the energy is not lost through open windows. The German Passive House Institute provides extensive information on their website.
VEKA recommends windows built with MD82 window frame profiles and triple glazing with Argon gas filling and Low-E coating for the lowest thermal transfer coefficients.