Windows and balcony doors

The company FENSTERNORM is a full-range provider and as such it produces, sells and installs window systems made out of synthetic materials, alu-plastic composites, wood, wood/aluminium and aluminium. In all this variance for materials, it is possible to use double glazing. This is necessary in order to reach the passive-house standard with a Uw value of 0,8 W/(m²K) or less.

Wood possesses good insulating properties and this makes it possible to reach the passive house standard. In order to reach this, it is necessary to use triple glazed wooden windows and door install spacers "warm edge". This is necessary in the case of framing materials in order to reach and overcome Uw-value 0,8 W/(m²K). In the case of PVC windows, the insulation performance of the frame depends on incorporated closed air chambers. Aluminium has the ability to conduct heat well and that's why it has particularly good U-values. This easy care and long-lasting material can be used for energy saving windows if it is combined with wood or synthetic materials. Aluminium windows are named this way because of all included elements that are made out of aluminium. Nevertheless, even aluminium windows have non-cellular plastic cores.

The measure for insulation capacity in general and for windows, in particular, is the heat transition coefficient (U-Value). In the past, people used the k-value. Lately, the U-value has prevailed and it is used now. It shows in Watts per Square-meter and kelvin (W/(m²K)), how much is heat loss from a certain area is by taking the temperature difference and the surface into consideration.

In the case of windows, we have different components made out of different materials and therefore, there are different U values.
`Ug` is the term for glass surfaces and in this term the letter `g` stands for glazing.`Uf` measures the values for frame components (here `f` stays for frame).`Uw` show us the value for the entire window that is composed of the two separate values for glazing and frame. Of course, the `Uw` value is the most decisive value for planners and homeowners. It shows how good the thermal insulation performance of the entire window is. The lower the `Uw` value is, the better the window insulates. As the calculation of the separate values is quite complicated, we're not going to explain it in detail here. We just want to mention one more fact: a window with `Uw` value of 0,8 W/(m²K) or less is suitable for passive houses which means that it's able to insulate particularly well. This can be explained using a heating oil equivalent very well. Through one square metre of a window with a `uw` value of 0,8 W/(m²K) there is so much heat that gets lost that can be produced with 7 L of heating oil.