What we mean by energy-efficient windows


The new lifestyle and the high energy costs of cooling and heating now necessitate the use of high-tech windows and aesthetics. So, in case you have decided to replace your windows, it is very likely that you will have trouble choosing the appropriate windows and this is absolutely normal!



Thermal break windows are widely known in the market as “Energy-efficient” aluminum frames. In particular, thermal break windows are often distinguished from conventional aluminum frames because of the use of special insulating material (usually polyamide, which is a poor conductor of heat) that separates window profiles in two parts, the external and the internal. In this way, high thermal and sound insulation are achieved. The thermal insulation of windows (thermal transmittance indicator) is measured in W/m2k, and this number determines the quantity of heat (in Watts) per unit of time that a window with a surface of 1m2 can penetrate when the temperature difference between the two surfaces of (inside – out) is 1 degree (1o C).

An aluminum frame, however, does not consist only of the aluminum profile, but also of the glass. Those two materials, glass and aluminum, have different coefficients (different thermal insulation – thermal transmittance). The thermal transmittance indicator of aluminum window is called Uf (U Frame) and the coefficient of the glass pane is Ug (U Glass). However, what really makes us understand the thermal insulation of the frame is the Uw (U window) coefficient that refers to the whole frame, precisely because the glass pane and the frame occupy a different surface each time depending on window’s dimensions (bathroom window, balcony door, etc.). Every aluminum frame manufacturer is obliged to mention the thermal insulation factor (thermal transmittance indicator or thermal conductivity) of each window.

Why to choose a thermal insulation windows?

The energy spent when using non-thermal insulation windows is at least 40% more on heating or cooling !!! How can you avoid big energy losses? Through thermal break, which is ensured by using special glass-filled reinforced polyamides in aluminum frames. The thermal break on windows is nothing more than a special material inserted between the outer and inner surface of the frame. Thus, there is an excellent result on energy saving as the thermal insulation frame effectively isolates the interior from the outside environment, preventing heat transfer. Having chosen a thermal-insulated window, you will definitely consider whether your windows are actually thermal insulated or not.
In the aluminum frames the thermal break on the side of the leaf and the frame is visible. Similarly, there is a heat-resistant polyamide in the case and you can see it under the center hinge, when lifting it.

What you should be cautious of when replacing a window?

The choice of window is a life choice and therefore, it is recommended that you be careful in order to avoid unpleasant results.

Do not just change the glass pane to existing non-insulating aluminum frames when you are recommended to do so. Replace the entire window so as to avoid the phenomenon of condensation, ie water vapor concentration.

We often observe water vapor and humidity in the frame, because aluminum as a metal is a good conductor of heat, due to the temperature difference of the interior with the outside environment. Especially in winter, the phenomenon of concentration of water vapor is observed on the cold surfaces of glasses. Thermal insulation frames are the best solution for dealing with this phenomenon.

Why is it important to install energy-efficient windows?

The larger surface of the window is occupied by glass. As a result, the choice of window requires a lot of attention. Glass panes are distinguished in conventional and energy glass panes, with significant differences in thermal insulation. The combination of two single glass panes, by inserting a spacer and by filling air or rare gases, creates the double glass.

Imagine, thanks to technological progress, a triple glass can now be mounted on advanced aluminum systems, which offers amazing levels of thermal insulation, sound insulation and safety! The use of new energy-efficient glass panes offers a better quality of life due to a better sound insulation and energy and money savings by reducing energy needs.

What to keep in mind when installing windows?

Last but very important detail! When installing, your energy-efficient windows should not come into direct contact with the wall or the floor, as this affects thermal insulation. Between the frame and the wall or the floor, plastic locks or special tires must be placed around to maintain the thermal insulation of the frame. Finally, all joints should be sealed with silicone.

Keep in mind that all the details we mentioned about energy-efficient windows are very important and the key factor in improving and certifying a home’s energy identity.