Windows can make an important contribution to thermal insulation and help save energy and heating costs. To ensure this, windows must have technically sophisticated insulating properties.
For optimal thermal insulation, the profile and glazing of the windows are important. Another important factor is the installation of the windows in the wall.
Standards for windows for thermal insulation
Thermal insulation is one of the most important parameters for windows. The U-value provides information about the thermal insulation quality of windows and is the heat transfer coefficient. The lower the U-value, the better the insulation. A low U-value is an indication of low heat losses.
Windows with a low U-value help save energy costs.
The unit of measurement for the U-value is watts per square meter and Kelvin (W/m²K).
There are three different U-values ​​for windows:
- Ug value for window glass: The Ug value becomes lower the thicker the glass package is. The window should consist of multiple glazing. In addition, insulation with a low-E layer and a noble gas filling of the space between the panes contribute to a lower value.
- Uf value for the window frame: The Uf value becomes lower if the material of the window frame has a high density or a pronounced chamber system.
- Uw value as window insulation value: The Uw value is the heat transfer coefficient for the entire window and should be as low as possible. For energy-saving windows, the Uw value should be less than 0.9 W/(m²K).
Another important parameter for thermal insulation in windows is the overall energy transmittance, the g-value. A g value of 1 means that the energy transmission is 100 percent. With a g value of 0, no energy at all passes through the windows.
The g value depends on the type of glazing:
- Single glazing: 0.75 to 0.87
- Double glazing: 0.65 to 0.70
- Triple glazing: 0.52 to 0.65
- 3-pane thermal insulation glazing: 0.38 to 0.55
- Solar control glazing: 0.25 to 0.50
The g-value should be adjusted to the energy balance of a building. For north-facing windows it should be as low as possible, while on the south side a higher g-value is recommended to take advantage of the solar energy.
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Tips for thermal insulation through windows
Optimal thermal insulation begins with installing the windows in the wall. Ideally, the windows should be moved to the insulation level in front of the outside wall. If this is not possible, the insulation should be inserted into the window reveal. Thermal bridges can be avoided if the insulation covers the window frame. An airtight wall connection can be created using joint sealing tape or connection tapes.
The Schüco windows are available in many variants and ensure a high level of energy comfort. They are suitable for new buildings as well as for energy-efficient renovations. An important factor for good insulation is the profile. The internal structure of multi-chamber profiles consists of several chambers filled with air. The Schüco windows have a five-chamber construction. They are available in PVC and aluminum. Schüco windows are also available with intelligent systems such as automatic ventilation and sun protection control.
Another important aspect for optimal thermal insulation is the glazing, with its important components, a warm edge and the properties of the glass surfaces.
The warm edge is an energy-efficient spacer between the individual window panes in double or triple glazing. With the warm edge, the noble gas filling cannot escape from the spaces between the panes.
The glass surface contributes to thermal protection. In order to provide summer thermal protection, a special coating is required. It ensures that only a small proportion of solar energy enters the building and air conditioning is not required. Depending on the sunlight, the texture of the surface can be individually adjusted. Windows are available with different coatings.
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Proper ventilation with thermally insulated windows
New windows close tightly and provide good insulation. However, sufficient ventilation is important to avoid mold formation. With insulated external walls, the risk of mold can be reduced to almost zero. A hygrometer is used to control the humidity in the home or office. The most efficient form of ventilation is cross ventilation. If this is not possible, shock ventilation should be carried out. Tilt ventilation is not efficient enough.
A ventilation system is not always necessary.
Window rebate ventilators are suitable for saving energy and ventilating efficiently. They help improve air quality. Window rebate ventilators are small components in the window frame that ensure permanent air exchange. However, window rebate ventilators are not a complete replacement for proper ventilation.
Suitable solutions for thermal insulation with windows
There are various solutions for optimal thermal insulation with windows. Windows are available in many sizes and designs and can be chosen to match the house. They are available with low Uf values ​​from 1.3 W/m2K. Generous window fronts can ensure good thermal insulation just as well as individual smaller windows.
Which g value is chosen depends, on the one hand, on the type of glazing and, on the other hand, on the location of the house and the desired use of solar energy.
In addition to good thermal insulation, good sound insulation and burglary protection are also important. In addition to thermal insulation, the glazing offers good sound insulation. Break-proof glazing and a strong profile are important for burglary protection.
The windows can be combined with the matching front doors, which also offer good thermal insulation. The doors also have multi-chamber profiles and can be selected with glazing.
