Your windows have a significant impact on your home’s heat loss and, consequently, your energy bill. Glass simply does not insulate as well as a well-insulated wall. The heat loss of a window, the thermal transmittance coefficient, is expressed as a U-value. The lower this value, the be
Your windows have a significant impact on your home’s heat loss and, consequently, your energy bill. Glass simply does not insulate as well as a well-insulated wall. The heat loss of a window, the thermal transmittance coefficient, is expressed as a U-value. The lower this value, the better the insulation value of your window.
However, please note that heat loss is not only caused by the glass, but also by the quality of your profiles. The entire unit must be perfectly airtight and watertight to form an effective thermal buffer.
We will take a closer look at both the different types of glass and the profiles.
For many years, double glazing—often colloquially referred to as ‘thermopane’—was the standard for residential construction. At the time, choosing double glazing was entirely justified, as the U-value of single glazing is around 5.8, while for double glazing, it is only 2.9.
What does this mean in practice? Suppose the outside temperature is 0°C and the inside temperature of your home is 20°C; single glazing will have an inside surface temperature of barely 5.6°C. With double glazing, that temperature will rise to 12.8°C under the same conditions. Quite a difference!
Today, however, there are more energy-efficient solutions than traditional double glazing. For highly insulating glass, an additional coating is applied to the glass and the space between the panes is filled with a noble gas mixture, specifically Argon. These two measures reduce the U-value to 1.0 and increase the temperature on the inside of the glass to approximately 17.5°C. If you opt for super-insulating triple glazing, you achieve a U-value of just 0.6, and the inside temperature will be 18.5°C. This is more than three times higher than with single glazing, making it the perfect choice for NZEB homes and passive houses. In this context, ‘NZEB’ stands for Nearly Zero-Energy Building.
If you choose highly insulating glass, your energy bill will drop significantly.
For every m2 of single glazing replaced with highly insulating glass, you save approximately 25 liters of heating oil or 23 m3 of natural gas each year. You can calculate exactly how much you can save in your home by installing highly insulating glass using the ‘Window Insulation Calculator’ from Fluvius.
To achieve optimal insulation results, your joinery must also be in top condition.
Furthermore, ensure that you do not install more opening windows than necessary. An operable window inherently causes more heat loss than a fixed window. It goes without saying that all windows must close perfectly and without gaps.
If you are considering investing in highly insulating glass, be sure to check the quality of your joinery. Good, sturdy, and airtight joinery with a favorable U-value can be retained. Minor damage can be repaired, but in all other cases, it is best to opt for a completely new window unit.
When you choose Keller minimal windows®, you are choosing the highest possible quality combined with an extraordinary minimalist design. The insulation values of this system are excellent. They maintain the indoor temperature and ensure optimal conditions throughout the year. The polyamide insulation strips, integrated into the outer frame, guarantee a thermal break, which reduces energy consumption and saves you money. In warm outdoor temperatures, these profiles keep the cool, air-conditioned air inside. You can also further protect yourself against heat penetration by integrating solar control glazing, which reduces the incoming heat rays from the sun.
