Keeping the house cooler in summer and warmer in winter can be a not so simple task. For this reason, more and more people are looking for solutions that allow them to optimize the thermal insulation of their homes. And one of the most sought after options is the low e glass.
But what is low-e glass and why is it so important? The first thing you should keep in mind is that these glasses usually have other names, such as “Low-E glasses” or “ATR glasses.” Whatever the case, keep in mind that we are talking about the same thing.
The most important element of low-e glass is that, through chemical treatment, incorporates a layer that is responsible for reflecting both exterior and interior energy.
This means that, for example, in the summer it does not allow all the thermal radiation of sunlight to enter through the window, nor does it allow the cold of the air conditioning to be lost. While in the winter it helps the heat from the heating to reflect on the glass and stay inside the home.
It is worth mentioning that low-e glass is often used in windows known as “double glass”, although it is not exclusive to them. But be careful, because DVH windows (hermetic double glazing or double glazing) do not always use low-e glass. That is why it is recommended to consult before making a purchase or installation.
Another interesting point to highlight is that the chemical treatment sheet is applied only to one side of the low-e glass. This means that, continuing with the example of double-glazed windows, the energy-reflecting layer is placed on the inner side of the glass on the outside.
The benefits of low-e glass
Currently, different reference parameters are used when identifying how insulating a glazing is. In the case of low-e glass, the best known is “U value”. This represents the thermal transmittance and is expressed in watts per square meter kelvin (W/m²K). Without getting into too technical details, what you should know is that the lower the number, the better.
This means that if, for example, a common double-glazed window manufactured in a 4/10/4 configuration—two panes of 4 millimeters each, separated by a chamber 10 millimeters thick—has a U-value of 3, 0 W/m²K. Using a low-E glass in the same configuration can reduce the U-value to 1.8 W/m²K. The change is noticeable. Of course, there are other configurations of windows and glass that are even more insulating.
It is also important to consult with an expert about the impact that other parameters such as the visible transmittancehe shadow coefficient (Shading Coefficient) and the solar heat gain coefficient (Solar Heat Gain Coefficient). It is worth clarifying, however, that this last parameter is almost not used in Europe, where it is usually replaced with the G valuewhich is practically identical.
The advantages of using low-e glass are obvious. As we already said, during the summer it helps prevent thermal radiation from sunlight from entering, while preventing the cold from the air conditioning from escaping through the glass. In winter, meanwhile, it prevents the energy loss generated by the filtration of internal heat from the heating to the outside. Likewise, it prevents the generation of the always annoying condensation or the “cold wall effect”.
This not only allows the temperature inside a room to remain at more constant levels throughout the day. Low-E glass also helps air conditioners or heaters are more efficient in their operation and consume less electricity or gas. Which can translate into savings of hundreds of euros per year.