Energy-saving windows

Interest in energy saving in our country is growing slowly but steadily. We increasingly look to Europe, where energy saving is already part of national regulations, including in the construction industry, and try to apply their experience in our conditions.

It's clear that a Soviet-era apartment block cannot be turned into an energy-efficient home, but significantly reducing heat loss is entirely possible. Often, the main heat loss occurs due to poorly sealed window openings. Old wooden frames are gradually being replaced by PVC windows, which provide good thermal insulation. However, not every PVC window is energy-saving.

What is the secret of energy-saving windows

The effectiveness of energy-saving windows comes from two components: the frame and the glazing unit.

To reduce heat loss via the frame, there are two options: either use as many chambers as possible, or employ a frame specially designed for use with a treated glazing unit (discussed below). When using coated glass, one or two chambers are often optimal. This significantly reduces window weight, ensures long-term performance without sagging, and thus maintains insulation between the frame and the opening.

Special attention is paid to the glazing unit when applying energy-saving technologies. This is not surprising, as a poor-quality glazing unit is often the root cause of heat leakage. Therefore, an energy-saving glazing unit with special glass, having a high thermal resistance coefficient, was developed.

Previously, a special coating based on metal oxide was applied to one side of such glass (known as K-glass). However, nowadays, a more advanced technology is commonly used: magnetron sputtering of ultra-thin oxides and metals (I-glass). It is this coating that gives the glass its heat-reflective properties.

Often, the glazing unit is also filled with inert gas. It acts as an effective thermal insulator, enhancing the window’s thermal protection.

Main advantages

Overall, energy-saving windows offer several positive qualities and benefits compared to standard ones:

• Lower utility bills. Due to a higher thermal resistance coefficient compared to standard double-chamber PVC windows, energy-efficient windows maintain indoor temperature, resulting in reduced energy consumption for heating. Savings may reach up to 30% according to various sources.
• Extended thermal comfort zone. This term refers to the distance from the window where air temperature remains suitable for natural human activity. For example, if it's -20°C outside, the surface temperature of a standard window glass is about +4 to +6°C. In contrast, energy-saving glass reaches +14 to +16°C. Thus, with energy-saving glazing, the thermal comfort zone significantly expands toward the windowsill, allowing you to place sofas, desks, or heat-loving plants near the window. Additionally, these windows reduce drafts, making them ideal for children’s rooms.
• Reduced impact of solar energy. This is a well-known issue: during summer, furniture and belongings in homes with standard windows heat up during the day and release heat at night, causing stuffiness and heat. Additionally, there’s damage: fading of wallpapers and curtains. Energy-saving glazing reflects solar energy 3–4 times more than standard glazing (but this applies only to I-glass). Hence, they help reduce electricity use for air conditioning, as the unit requires less power to cool the room.