Relatively recently on the construction market finishing materials a thin polymer film has appeared, with the finest coating of gold, silver or chromium-nickel alloy, the thickness of which does not exceed several nanometers and is commonly called heat-saving film for windows.
Its effectiveness in the home is determined by a number of factors, taking into account which you can actually achieve a heat-saving effect, saving up to 30% of heat consumption in an apartment or on a balcony during the cold season, but you can also get a number of completely undesirable effects that this material has.
How does film work?
The basis for the production of the film is the polymer polyethylene terephthalate (PET), the thickness of which, depending on the manufacturer and operating conditions of the heat-saving film, can vary from 80 to 200 microns. Due to the high ductility of the heat-saving film, it can, to some extent, increase the strength of window glass, especially when glued directly to its surface. But most big advantage is something that is accidentally broken window glass will not shatter into small fragments. They will remain tightly “glued” to the film in the window frame.
But protecting window glass, of course, is not the main purpose of using heat-saving film.
Thanks to a microscopic layer of rare earth metals deposited on its surface by plasma evaporation and subsequent deposition of metal vapor in an argon environment, a layer is formed that, without interfering with the penetration of rays of the visible spectrum through the film, changes, due to refraction, the transparency of the film for rays of the UV and IR parts of the spectrum Sun. These rays are not visible to the human eye. But IR (infrared) rays are responsible for heat transfer; their film, when refracted, reflects into the room, and it is due to this that its “heat-saving” effect is manifested. But it reflects the rays of the UV (ultraviolet) part of the spectrum, which make up a significant segment of the sun’s light, preventing them from penetrating into the room.
The sun's UV rays have a strong ionizing effect. Being vital for the body in small doses, they contribute to the production of D vitamins in the human body, normal photosynthesis of indoor plants and purification of indoor air from pathogens.
When is it advisable to use film?
Most manufacturers recommend sticking heat-saving film on the windows of an apartment or balcony only during the cold period - from October to March. It is during this period that protection against heat loss through windows takes place. The rays of the Sun, trying to penetrate into the room through the windows, carry practically no heat with them in winter, so the reflection of the UV part of the Sun’s light does not cause discomfort, since the films are absolutely transparent and do not give a tinted effect. But the IR (infrared) rays emanating from heating devices, trying to leave the room, are, on the contrary, reflected into the room. This is where the heat-saving properties of the film manifest themselves. Another important factor in which the heat-saving effect is most fully manifested is the technology of applying heat-saving film to glass.
There are two types of films: the most common are heat-shrink films, which can stretch when they are heated warm air from a household hair dryer and film, directly glued to the glass using the “wet” method, using soap solutions.
In the first case, glued to double sided tape The film on the window frame also plays the role of a “third glass”. A thin air layer is formed between the window glass and the film, which, like the air between the glass panes, is an excellent protection against heat loss.
Negative properties of film
In addition to the positive ones, the film also has negative properties.
The most serious of these is the almost complete reflection of the sun's UV rays. Films suffer most from this negative property houseplants, growing on a windowsill or balcony, which begin to wither and die. Therefore, if you use winter period heat-saving film for windows, be sure to arrange for plants located on your window sills to be illuminated for 12 hours with phyto-lamps that provide the correct radiation spectrum necessary for normal plant growth and to compensate for the lack of natural light from the Sun. True, in this case, there can be no talk of any “energy saving” in your apartment. Even very economical phytolamps on LEDs, with daily illumination of plants for 12 hours, will completely “absorb” your savings on heating the room.
The second negative effect of heat-saving film applied to the windows of an apartment or balcony is its complete ineffectiveness in spring and autumn periods. When the heating in the apartment is not yet turned on, or is already turned off, the film prevents the penetration of the sun's heat from the street. It becomes cold and damp on the balcony and in the apartment, especially in spring.
Another disadvantage of heat-saving films is their ability to reflect radio waves. Radio signal coming to you TV antenna or mobile phone, will be reflected by the metal coating of the film, and the signal coming from your mobile device– will also be reflected inside the apartment.
That's why, cellular in houses where the heat transfer film is glued to the windows, as a rule, it is very bad.
How to mount film
It depends on what kind of film you are using - heat-shrinkable, self-adhesive or soap-based. In any case, you will need an assistant. The film can be sold in sheets folded in half or in rolls.
First preparatory stage is washing and drying the window.
After which a layer of soap solution is applied to it from a household sprayer. To prepare it, you can use children's shampoo not colored with pigments or colorless dishwashing liquid. After that, a film cut to the size of the glass is applied to the generously moistened glass of the window. Be sure to first use the top edge, and use a soft rubber roller or a rubber scraper for washing windows to remove excess from under the film. soap solution. First, from top to bottom - in the middle of the glass, and then - from the glued middle of the film to the sides. If possible, avoid the formation of large air bubbles. The film will not stick in these places. Small wrinkles and liquid bubbles will disappear on their own as the film dries and the film will completely straighten out.
In a similar way, stick and self-adhesive film. Only the base protecting the adhesive layer is not removed from the entire film at once, but a narrow strip is peeled off from the upper edge of the film. It takes two people to work. Having glued the top edge, the person at the top smoothes the glued film with a soft cloth, and the person at the bottom gradually removes the protective layer, pulling it towards himself. The main thing is not to rush.
Installation of shrink film is also best done by two people. Along the perimeter window frame double-sided tape is pasted, a blank 2 cm larger than the glass is cut out of the film, and glued to the tape around the entire perimeter. Top first, while an assistant must pull the bottom edge of the film by the corners, preventing premature gluing of the film. The resulting wrinkles and folds are not scary.
After gluing, the film is blown with hot air from a hairdryer, and it straightens and stretches itself. Shrink film is especially effective on the balcony, where it acts as a second or third glass.
Let's sum it up
When planning to use heat-saving film on windows in your apartment, weigh the pros and cons. Perhaps it would be cheaper to insulate a balcony or windows if they are wooden, or a freezing wall or floor? The film is not a radical method of insulation, moreover, it requires annual replacement.
Once fashionable and seemingly unsurpassed in quality plastic double glazed windows today they are inferior in efficiency and practicality to heat-saving windows. The fact is that even when installing the most modern PVC windows, up to 40% of room heat escapes through them. Energy-saving designs can reduce heat loss.
What is a heat-saving window?
Energy saving windows are PVC double glazed windows with special spraying or intra-chamber inertial gas, which effectively reduce the level of heat exchange between the room and the street. Innovative constructive technology allows you to maintain the same temperature in the apartment in winter and summer with minimal use of additional equipment.
The kind that allows internal space not to overheat, but the furniture and wall coverings do not fade. Special coating glass makes it possible to abandon the use of multi-chamber profiles in the design. And this, in turn, helps reduce the load on the fittings and simplifies carrying out installation work. In addition, such windows do not fog up and are not susceptible to condensation. They are pleasant to the touch and even with negative street temperatures, inner side always stays warm.
Benefits of energy-saving windows
- Thermal insulation. The main advantage of energy-saving windows is their reflective properties. Regular glass heat up quickly and cool down just as quickly. Because of this, the heat in the room, especially in winter, goes outside. That is, resources for heating the room are practically wasted. Special coating minimizes heat radiation during external environment, thereby maintaining the optimally high temperature at home. In summer, the room will be protected from overheating. Even though the sun's rays will enter the room, the heat will be reflected outward.
- A light weight. Single-chamber energy-saving window designs are twice as effective as three-chamber ones. This means that with the same technical characteristics, the first ones will be much lighter. Such windows can be installed in almost any environment without significant restrictions.
- No condensation. Droplets of water appear on glass due to temperature changes. Outside, cold air quickly cools the glass sheet, which, when in contact with warm indoor air masses, high humidity creates conditions for condensation to occur. Energy-saving products will not be as cold in winter as standard ones. Therefore, the problem with temperature changes, which causes glass fogging, disappears.
- Burnout protection. Bright rays of light, coupled with ultraviolet radiation, negatively affect the brightness of the color of furniture and any other artificial surfaces. Therefore, valuable exhibits of museums and exhibitions are displayed and stored in darkened rooms. Special coating on energy-efficient glass prevents the penetration of ultraviolet rays, which allows you to save appearance objects in the room.
Technical features
Specifications energy-efficient windows vary depending on the type of product. K-glass has a higher light transmittance, and I-glass has an increased thermal efficiency.
In order to clearly evaluate technical features heat-saving windows, it is necessary to consider the change in the heat transfer resistance coefficient when using energy-saving glass.
For comparison, let's take the usual single-chamber double-glazed window 22 mm thick and M1 glass (thickness 4 mm, distance frame width 16 mm) and a two-chamber window 32 mm thick (M1 glass, thickness 4 mm, distance frame width 16 mm). When measuring the heat transfer resistance coefficient, we obtain the following results: in the first case - 0.3 m2°C/W, in the second - 0.49 m2°C/W.
When installing heat-reflecting glass into a single-chamber structure, the heat transfer resistance coefficient will double - up to 0.6 m2°C/W. That is, the value of the indicator will be higher even than that of a two-chamber window, while the weight of a single-chamber structure will be 10 kg/m² less.
Kinds
There are several methods for creating energy-saving window designs:
A method of spraying a special composition onto a surface.
- K-glass (hard). Manufactured using pyrolysis technology, when hot glass surface metal oxides are deposited. As it cools, the glass and the applied layer are firmly sintered, providing the hardness of the canvas and increased heat-reflecting properties.
- I-glass (soft). The method involves applying a three-layer silver dielectric to a glass sheet under vacuum conditions. Another layer is sprayed on top - titanium oxide, which performs protective functions. The result is glass that is inferior to K-glass in impact resistance and resistance to mechanical stress, but has higher technical characteristics in the field of energy saving.
Method of applying a special film.
Metal oxides are also applied to the film, and then it is glued to ordinary glass.
Method of filling the interglass space with gas.
Besides existing methods To create energy-efficient windows, there are multifunctional designs that are created using multi-layer coatings. The middle functional layer (silver oxide coating) provides the heat-reflecting function of the structure. The role of the protective outer layer is absorption and reflection sun rays, reducing their quantitative penetration into the room. This allows you to protect the room from overheating in summer and dazzling sunlight.
In addition, the design can be supplemented with a layer that affects the light transmittance of the glass, its shade and appearance.
Multifunctional windows are characterized by energy-saving properties and the effective ability to keep a room pleasantly cool in the summer heat. Also, if you use a mirror coating as one of the layers, you can ensure privacy.
The use of films with different light transmittance allows you to avoid the appearance of sun “bunnies” in the room and glare on TV or computer screens. And installing glass with colored film helps create decorative interior compositions indoors.
To produce energy-efficient windows from the ISOLUX company, manufacturers can order heat-saving ClimaGuard ® double-glazed windows with a thickness of 4 mm with protective layer based on silver, as well as packages with I-glass 4 and 6 mm. Both are filled with argon.
Advantages of heat-saving double-glazed windows
Durability and reliabilityWindow systems with heat-protective double-glazed windows are lighter and place less load on the fittings, extending their service life. Low-emissivity spraying is maintained throughout the entire life of the system.
Effective thermal protection in winterThe design insulates heat much better than the standard one, although it weighs less. A package with one chamber made of two energy-efficient glasses is 1.5 times lighter than a standard one and retains 25% more heat in the room.
Comfortable microclimate in summerIn the summer heat, the bags reflect heat waves outward and keep the room pleasantly cool.
Heat in the room is provided by two sources. The first is solar radiation entering the windows from the outside - ultraviolet, visible light and short infrared waves; the second is heated objects and heating devices in the room, from which long infrared waves emanate. Helps prevent heat loss I-glass with low-emissivity coating, reflecting infrared radiation into the room. Ion-coated glass is installed first so that the coating is located inside the glass unit. Silver ions on the surface of the thermally efficient package create a mirror effect. In contact with heat waves from heating devices, they direct the radiation back. As a result, heating intensity can be reduced by up to 50%.
Energy packagesClimaGuard®Solar multifunctional. They solve two problems: in winter they retain heat in the room and in summer they protect the room from the sun. One layer of their coating reflects heat waves from heated surfaces into the room, the other retains up to 60% solar energy. Silver coating does not affect the transparency and optical properties of glass, helps save on heat supply, and eliminates fogging of windows.
Application and prices for heat-saving double-glazed windows
We offer affordable designs High Quality. All of them are certified and meet the requirements of GOST. Thermal packages are popular in glazing:
- cottages,
- city apartments,
- shopping and business centers,
- medical institutions.
The cost of such products depends on the choice of their modification - with I-glass or multifunctional ClimaGuard ®, on the area of glass filling, and the thickness of the glass. The energy-saving glass package quickly pays for itself - it saves up to 40% more heat compared to its standard counterpart.
Heat-saving double-glazed window wooden windows has spacer frames made using plastic, which eliminates the appearance of a “cold bridge”, creating a thermal break. This design allows you to almost completely eliminate freezing of the glass unit at the edges and significantly reduce the likelihood of it fogging up. Additional insulation windows are made by filling the chambers with argon and using low-emission energy-saving I-glass.
What is I-glass
I-glass is an infrared (thermal) mirror that reflects thermal radiation back into the room. At the same time, I-glass does not interfere with the passage of visible light from the Sun into the room. This glass is made by applying a thin metal film to regular window glass. I-glass is installed in a double-glazed window with the film inside, so the double-glazed window can be easily washed without fear of damaging the coating.
Heat saving for OSB windows
At your request, we will install heat-saving double-glazed windows with a thickness of 28 mm and the formula 4-20TR + Ar-4I (single-chamber, consisting of M1 glass 4 mm thick, a chamber 20 mm thick, filled with argon and having a frame with a thermal break - TP) in OSB windows. energy-saving I-glass 4 mm thick) or 4I-8TR+Ar-4I-8TR+Ar-4 (two-chamber, consisting of two chambers 8 mm thick, filled with argon and having frames with a thermal break, two energy-saving I-glasses 4 mm thick and one M1 glass 4 mm thick).
Heat package 4-20TR+Ar-4I
Specifications
Single chamber package light weight, which reduces the load on the fittings elements, extending their service life.
The presence of only two glasses increases the light transmission of the window.
Optional
- Self-cleaning glass (Active)
- Solar control multifunctional glass
- Soundproofing thick glass Pilkington
Heat package 4I-8TR+Ar-4I-8TR+Ar-4
Specifications
Thanks to the presence of two cameras better thermal insulation and sound insulation.
Optional
- Self-cleaning glass (Active)
- Solar control multifunctional glass
- Soundproof thick glass Pilkington
Heat saving for Eurowindows
Maximum heat saving for wooden euro-windows is achieved by installing two-chamber thermal packages with the formula 4-12TP+Ar-4I-14TP+Ar-4 (38 mm). The double-glazed window consists of one M1 glass 4 mm thick, two chambers 12 and 14 mm thick, filled with argon and having frames with a thermal break, two energy-saving I-glasses 4 mm thick.
Are double-glazed windows with argon profitable? Is it worth paying extra for modern technologies? What are the advantages of Rehau energy-saving windows? Are they worth the money? There are many offers on the market for installing energy-saving windows, but can you trust them all? How to distinguish a fake? These and many other questions concern modern man who started major renovation to your own “eye” at home. Let's try to see to what extent replacing a window with a high-tech package will help save energy, heat and money, and to what extent this is just a myth.
Old and new
Until recently, it seemed that metal-plastic was the best, most technologically advanced, efficient windows. They did not stay in first place for long: less than five years had passed before new, energy-saving technologies began to push them out of the market. plastic structures. Manufacturers are paying attention, they let in more light, retain heat better, which means that you only need to install them, and it’s time to urgently change the old ones. Of course, replacing windows is a good idea, but it is not cheap, so a reasonable person would think twice about whether such expenditure of money is justified.
The main idea of the new product among window technologies- effective prevention of heat loss through the window opening. As studies show, on average, through this section in environment Almost half of all heat lost by a home is lost. As manufacturers assure, and this is also indicated in some reviews, energy-saving windows are a third more efficient than metal-plastic ones - and therefore incomparably better than old wooden structures.
We lose heat: how?
Why do they work? What is the logic of this design? Manufacturers pay attention: during installation modern system It is necessary to pay special attention to the glazing area, since the frame is no more than a fifth of the entire window area. Energy-saving glass is effective due to the type of glazing used, the number of glasses used in the manufacturing process of the structure and the distance that separates them from each other. In addition, the efficiency of heat conservation is determined by the material from which the frame is made and the gaseous medium filling the space between the glasses.
Modern double-glazed windows - ordinary two-chamber windows- with high tightness, they cannot be considered sufficiently effective in terms of energy conservation. This is due to the use of ordinary glass in their design, which conducts heat well. In order for double-chamber windows to retain energy indoors, it is necessary to use specific insulators. You can identify a window with low thermal conductivity in the cold season - it cools down from the inside, and when humidity rises, condensation quickly forms. All this indicates low efficiency of the system.
What's the difference?
What are these - energy-saving windows? Many ordinary people, buying ordinary structures made of metal-plastic, heard from sellers and managers that these are real windows assembled using this technology. During operation, many were disappointed. When installing a conventional structure made of polyvinyl chloride, the tightness will be excellent, but this greatly disrupts the normal exchange of air, which negatively affects humidity, condensation occurs and falls, which is immediately visible on the cold glass of the window.
What are these - energy-saving windows? These are structures that inner surface does not cool even when severe frost. So, if the temperature outside drops to -26, and inside the room is heated to the standard 20 degrees Celsius, the surface of the window maintains the temperature at 13 degrees. Of course, if the room is very high humidity, even this will not save you from condensation, and yet its amount will be much lower than when installing PVC windows. A reliable manufacturer will definitely tell you that these are energy-saving windows, and will also explain how the design works. It must be remembered that effectiveness is maintained only if integrity is maintained.
Features of different options
How to check whether the manufacturer offers energy-saving windows or regular ones? You need to carefully study the specifications for the proposed product. For example, if this regular window, then the frame is made of aluminum. In fact it is a bridge of cold. But the effective window structure is made from composite polymer materials. Alternative option- steel framed in plastic. Thanks to this addition, the thermal conductivity of the metal is greatly reduced, increasing the efficiency of the structure as a whole.
Which of the energy-saving windows on the market are better and which are worse? How to determine? The best option are two-chamber designs - they are always warmer than one chamber. If the package consists of two glasses, this will be one camera. Some designs include as many as three chambers - these are the warmest. Considering that these are energy-saving windows, you need to pay attention that inside they are filled with inert gases that do not conduct heat.
Geometric parameters
IN general case a single-chamber design consists of two glasses, the distance between which varies from 6 to 16 millimeters. If the system consists of two chambers, the glasses are placed at a distance of 6-12 millimeters from each other. The specific value is determined by what kind of energy-saving windows are installed and what type of profile is used in the design.
It is believed that best option- this is the distance of the glasses from each other by 14-16 millimeters. Both an increase in the distance and a decrease in it lead to a deterioration in heat retention performance.
Saving energy: how does it work?
Others will rightly think: they just replaced the windows a couple of years ago, and now they are offering another new product. Spending money on constant new things is stupid, and it’s not cheap. Why not buy a simple one for the windows, stick it on and live in peace? The option, by the way, has a right to exist, although it cannot be considered the most optimal. However, before deciding to save money, it is worth considering what features of thermophysics are used in the design of new types of windows - perhaps potential buyer will understand that he really doesn’t need it, or, on the contrary, will decide that the investment is worth the money requested for it.
It's worth remembering that classical methods insulation of floors and walls, not applicable for design window openings designed to let natural light into the house. The newest technologies for constructing window structures are developments that make it possible, while reducing heat loss, to increase the percentage of light transmitted by the glass.
Heat energy: general course
There are two options for the propagation of thermal energy - rays and convection. In the first option, the source is considered as an emitter in the infrared spectrum. The radiation intensity is directly determined by the level of surface heating. Convection is direct heat exchange when air warms up or cools down.
Ordinary glass does not pose an obstacle to heat rays, that is infrared spectrum. That is why energy-saving films for windows can really bring certain benefits - they do not allow this radiation to leave the walls of the home so easily. In production conditions, glass installed in energy-efficient double-glazed windows is coated with special components - non-ferrous metal sulfides and silver plating. You can also use special films - they are also applied in industrial conditions. With high-quality surface treatment, the ability to reflect infrared radiation increases by an average of 80%, which means heat loss is significantly reduced. The use of modern technologies makes it possible not to harm the ability of glass to transmit light - up to 72% of the sun's rays easily pass through the barrier, and 28% of the difference does not play a role in the level of illumination perceived by a person. If in winter such a window will retain heat, then in summer its benefits are no less relevant - it effectively reflects the radiation emitted by the sun.
Spraying features
No matter how many cameras there are in the window system, spraying is done only on one glass and only on one side. To ensure longer service life, the treated side is usually located inside the first chamber, on the street side. There are several varieties of layers used to save energy.
One of the most common options is k-coating. It is considered hard because it has increased strength and resistance to mechanical damage. Created using metal oxides. To apply, the surface is first heated to very high high temperature, therefore, the least resource-intensive spraying process is during the manufacture of a double-glazed window.
An alternative option is i-coating of two layers. It is destroyed to a greater extent under the influence of aggressive mechanical factors, therefore it is classified as soft. First, a silver layer is sprayed, for which the glass must be completely prepared and placed in a vacuum. The second layer - protective - consists of titanium oxide.
What's better?
Some experts point out that both described technologies have been used for quite a long time and cannot be considered the most effective and reasonable options. In European countries, in the last few years, selective methodologies have been actively used, in comparison with those described, showing parameters that are approximately three times better. At the same time, new products are more economical for the buyer. Thus, the Swiss company Euroglass proposed the “Zero” option, which, given the difference in cost per square meter glass is only ten dollars more expensive, but retains heat two and a half times better. However, it is currently unclear when the most Hi-tech will reach our country. Perhaps in the near future: we will see.
What's the threat?
It is believed that the main advantage of k-technology is that the coating can withstand possible mechanical damage. At the same time, practice shows that in most cases these are typical only production process. When the glass unit is assembled, the coating ends up inside, in a protected sealed chamber, where nothing threatens it, so there is no real difference for the user - if, of course, the manufacturer is reliable and the energy-resistant glass is carefully manufactured.
At the same time, surveys have shown that many do not see the difference between these two technologies. There is an emission, but it is too small to be felt without using high-precision measuring instruments. If we take the base temperature outside as 26 degrees below zero, while at the same time the heating in the living room is maintained at 20 degrees Celsius, the k-glass will cool to 11 degrees, and the i-technology will show a level of 14 degrees. The real benefit and difference in the presence of condensate is usually not noticeable, so you can safely choose any of the options.
Is it worth doing?
As can be seen from the experience of numerous users, installing an energy-saving window helps to significantly reduce the amount of condensation generated, making it easier to maintain air humidity at a comfortable level. The microclimate in a living space improves significantly, especially in comparison with classic metal-plastic structures. When using an energy-saving window, the edge zone does not freeze and ice does not form. If the user is currently encountering such problems with the window system, it is worth seriously considering replacing the design with a more advanced one.
Inert gas: effect or beautiful words?
Typically, windows are filled from the inside with krypton or argon. In general, it is believed that such gas helps reduce heat loss through glass. When explaining the logic of the operation of this system, it is necessary to remember that the air inside the living space is warm; it is constantly in contact with the colder surface of the glass, transferring the accumulated heat. The lower the surface heating, the faster the heat is released, but when used energy saving technology the indicator goes down. When the glass heats up, it gives off heat to the air filling the chamber space. It transfers energy further - to the outer layer of glazing and into the world. The lower the temperature of each layer, the more intense the heat exchange process occurs.
In many ways, the efficiency of heat conservation depends not so much on the filler, but on the distance by which the glass is separated. If it is large enough, then the glasses are spaced apart from each other, they can transmit and receive a lot of heat. If the distance is small, then the energy is transferred directly. A range of 6-16 millimeters is considered effective.
And why do we need gas?
If instead ordinary air pump inert gas between the glasses, heat will be transferred at a lower speed, since these substances are characterized by low thermal conductivity. In addition, the glass filler will be completely devoid of water molecules capable of forming condensation. Water is an excellent conductor of heat, and the less it is, the more efficiently energy is stored.
Is it worth overpaying for window packages assembled using this technology? It is believed that argon reduces energy losses by approximately one tenth, which in reality to an ordinary person very difficult to notice. Most users note that they did not feel any significant difference. On the other hand, it cannot be denied that the use of special gases improves the performance window systems, and at high level keeping warm can provide additional improvement. But when installing a regular plastic window, filling the chambers with argon or krypton does not bring any real benefit - the energy losses are large enough that a tenth does not play any significant role.
And finally...
It has long been considered that one of the leaders in the field of manufacturing energy-saving and simple plastic windows- Rehau company. The price of its products is not the lowest, but many are willing to pay this amount to get a durable design. As experts say, one of best products on the market are Geneo windows developed by this company. The advantage of the design is the presence of a well-thought-out ventilation system, due to which the humidity is not so high. As can be seen from the reviews, when collaborating with an authorized supplier, there will be no problems with the quality of the system. On average, the price for one window is about 25 thousand. Is it worth spending that kind of money? It is up to each buyer to decide for himself: the amount is quite large, but these structures will retain heat better than most of the competitors on our market.