How do energy-efficient windows work?

Energy costs are constantly rising, which hits our budget, especially in winter, when rooms heating requires heavy expenses. It has been proven that a significant part of heat, up to 40%, escapes through the windows. They attempt to solve the issue by producing special energy-efficient structures that retain heat in winter and prevent the cold from escaping from the air conditioner in summer. Let’s find out what these energy-efficient windows are and how they work.


First, a few words about the advantages of energy-efficient systems. They:

  •   Return up to 70% of the heat to the room.
  •   Improve air conditioning efficiency in summer.
  •   Reduce heating costs.
  •   Hardly ever collect condensation.
  •   Provide high translucency.

Let’s now see how it all works.

What does an energy-efficient window look like?

Only 10 to 15 years ago, the energy-saving functions of double-glazed windows were evaluated by the number of air chambers in the profile. They believed that the greater the number, the less heat would escape outside. It is partly true, though, and double-glazed windows with air chambers are much more efficient than those without them. Yet all this only applies to profiles that take up only 20-30% of the window construction. Other losses fall on glass that nobody has dealt with until now, especially in terms of improving its energy efficiency. And so it was that the heat leakage was combated only in one direction, and not in the most important one.

Since then, the situation has changed due to the development of technology: manufacturers started paying more attention to the energy-efficient properties of glass and began to apply a special spray coating.

The third component of energy-efficient windows is an air chamber with argon injected inside. Why this inert gas? It takes too long to weather: even 10 years after the start of use, its amount within the chamber will be enough to perform the insulating functions, though it should be noted that this is subject to quality window installation.

A standard two-chamber energy-efficient window includes:

  •   Three- or five-chamber profile.
  •   Three panes of low emissivity insulation glass.
  •   Two air chambers between the glasses with argon injected inside.

So now, an energy-efficient window represents a combination of elements aimed at improving the thermal insulation characteristics of the entire system, rather than its individual parts.

Production of low emissivity insulating glass

The majority of manufacturers use i-glass, or in other words, glass with a soft insulating covering. It is called “soft” because of its low strength; in this connection, the coated surface is usually placed inside the air chamber during installation.

The energy-efficient coating is based on tin and silver ions. It is applied by spraying and works like a mirror: infrared radiation (heat) passes through the regular glass and is reflected by the energy-efficient surface back into the room.

Another popular choice is multi-functional glass that only differs from i-glass in its structure and reflects both the heat coming from the inside and the cold coming from the outside.

Please keep in mind: both multi-functional and i-glass have nearly the same degree of transparency as standard glass and do not distort the color reproduction in any way at all.

Filling chambers with gas

To enhance the quality of thermal insulation, they inject inert gas or, in some cases, dried air into the chamber. However, the first one has the advantage of lower thermal conductivity. The gas is injected into the chamber through a special valve. They usually use argon as an inert gas as it is safe for people, animals, plants, and does not vaporize for a long time.

Another essential function that argon performs in the overall construction is the protection of the energy-saving coating against oxidation, which prolongs the system’s service life.

Remember that installation plays a major role. The construction must be sealed with special compounds and be completely airtight. Responsible manufacturers work hard to ensure that this parameter is up to par.

Energy-efficient profile

They started making profiles with air chambers earlier than energy-efficient glass. However, it is the integrated approach that ensures the best effect on the system.

The number of chambers can vary: there are three-, four-, five- and six-chamber constructs. The best-selling items today are three and five-chamber products, and while the first refers to the economy segment, the second is used for the manufacture of high-end windows. The operating principle of chambers in the profile is simple: the air inside the construction retains heat, so the more of them, the more effective it is.

Hence, by enlarging the chambers inside the profile, using energy-efficient glass, and injecting argon into a double-glazed window, you can significantly reduce the heat loss inside the room. According to experts, if you install such structures in all rooms of the apartment, you can save up to 35% of the money on heating over the season. So, make your conclusions.

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