Windows and the quest for energy efficiency

The window is undergoing a transformation with the purpose of improving its sustainability. Increasingly, the characteristics of this element are focused on addressing energy losses that decrease comfort in homes. In fact, approximately 25% of the leaks in a house with poor insulation occur through the façade, and window openings constitute the most critical points in this regard. Therefore, buyers demand aspects ranging from the performance of windows to reduce energy consumption in the home to the origin of the raw materials, the manufacturing process and the type of materials to be used (see here our article on 37 sustainable construction materials).

Characteristics of a sustainable window

When looking to choose a window, it's crucial to consider several essential aspects:

• Required level of thermal insulation: thermal properties can be evaluated through the energy label of windows.
• Sound insulation needs.
• Degree of resistance: depending on the purpose, it may be necessary to opt for a stronger window, as in the case of glazed facades, or a less resistant one, as in interior windows.
• Desired functionality: There are several opening options that provide different functions and aesthetics.

Types of sustainable windows

The most common categories include:

• Wood: Although they can provide good thermal insulation, they are more vulnerable to environmental degradation, implying the need for constant maintenance. They are often chosen for their aesthetic value.
• PVC: Frames made of PVC stand out for their noise reduction capacity, but they generally have lower thermal insulation.
• Aluminum: Aluminium frames are the most resistant to environmental wear and tear and offer the highest levels of insulation, both thermal and acoustic.

Circular windows

According to a study at the University of the Basque Country (UPV/EHU), the notable influence of window design in achieving significant energy savings has been demonstrated. In addition, the importance of considering the different components that make up a window is highlighted.

This analysis, based on the guidelines of the Technical Building Code, focuses on the system and the preconstructed window product. Then, the architect and professor at the UPV/EHU, Fernando Mora, considered how to reduce energy consumption in buildings by exploring various possible combinations between the preconstructed hollow-window system and its impacts in terms of energy.

Based on the results obtained in this research, it is concluded that windows with a circular design and a single frame, either fixed or folding, present the most efficient solution in terms of energy savings.

However, it is important to note that this study did not take into account factors such as the environment in which the window is installed or local weather conditions. Therefore, the conclusions of this study may vary depending on the specific location where the construction is planned to take place.