Heat-reflecting double-glazed windows - manufacturing technology, advantages

Victor built a country house with an area of ​​100 square meters. meters. The heating is electric. Annual heating costs in winter are 20,000 rubles. One of the reasons for the high costs is the loss of heat from the house, when the street is essentially heated. Replacing conventional plastic windows with energy-saving ones made it possible to significantly save on heating costs.

Maintaining the temperature of the house allowed us to halve the operating time of the boiler and, accordingly, the costs were halved. This made it possible to win 10,000 rubles in just one winter season with new windows.

Windows and doors are heat conductors

In winter, a house loses heat through windows and doors (as illustrated by the results of thermal imaging studies) more than through all other elements and structures. Walls, roofing, and floors in a private house also conduct heat, but due to the use of materials more resistant to thermal conductivity, these losses are not so significant.

Ordinary glass is not designed for serious protection against heat loss. To reflect heat (keep it indoors), special glass with a heat-reflecting coating is used.

Advantages of a “soft” heat-reflecting coating

The cost of double-glazed windows with a “hard” coating is higher than the cost of windows with a “soft” coating. This cannot but affect prices. A rational consumer will choose heat-reflecting double-glazed windows with a “soft” coating. If we consider that they also provide more efficient heat reflection, the advantages of double-glazed windows with a “soft” coating become completely obvious.

It is also important that the method of applying a “soft” coating is more environmentally friendly than the technology for obtaining a “hard” layer. In our era, fraught with environmental collapse, this circumstance alone is enough to give preference to a “soft” coating.

The “soft” coating gives the glass a certain tint, which is very welcome by everyone who has a developed aesthetic sense. There is room for your imagination to run wild when decorating your home.

The advantages of a “soft” heat-reflecting coating include the fact that it lies on the glass more evenly than a “hard” one. This has a positive effect on the efficiency of heat reflection.

Heat saving

Preserving room heat in winter is the main task in the long winter in the northern hemisphere. The heat is largely lost in the form of infrared radiation passing through the transparent glass unit.

Infrared radiation is also called “thermal radiation” because infrared radiation from heated objects is perceived by the human skin as a sensation of heat. In this case, the wavelengths emitted by the body depend on the heating temperature: the higher the temperature, the shorter the wavelength and the higher the radiation intensity.

Required minimum heat transfer resistance of windows

According to accepted standards (SNiP II-3-79 Construction Heat Engineering, GOST 24866-99 Double-glazed windows for construction purposes), in houses in Russia the heat transfer resistance coefficient of windows should be from 0.3 to 0.8 m²°C/W, depending depending on the region and degree-day of the heating period. The value of 0.72 m²°C/W corresponds to a frost-resistant two-chamber double-glazed window with a heat-reflecting coating on at least one of the glasses, and a five-chamber profile, the installation depth of which is at least 70 mm. For Moscow, according to current standards (MGSN 2.01-99 Energy saving in buildings), a value of no lower than 0.54 m²°C/W should be taken. In warmer regions of Russia, the coefficient of resistance to heat transfer of windows can be about 6 m²°C/W.

At the same time, in most countries of Western Europe the requirements are stricter, and windows must have a corresponding indicator at the level of about.8-0.9 m²°C/W. Considering that building codes will only become more stringent, and the cost of energy and heating tariffs will only rise, when developing a house project or replacing old glazing in an apartment, it is wise to initially plan to install translucent structures with improved heat-saving properties.

High-quality double-glazed windows will last 30-50 years and during this time they will definitely pay for themselves thanks to savings on heating. If you plan to build a house that uses alternative energy sources and does not depend on main networks, you cannot do without highly energy-efficient glazing. The heat transfer resistance coefficient of windows in this case must be at least 0.9 m²°C/W, otherwise the cost of heating the home will be enormous, and in some cases the house simply cannot be heated. For example, one of the new products of modern windows, Kaleva Titan Plus, effectively provides heat saving (heat transfer resistance coefficient 0.92 m²°C/W).

A modern window is a high-tech product, the heat-saving properties of which largely depend on the features of its profile and glass unit, which are complex engineering structures, of course, subject to proper installation of the window and high-quality finishing. All serious manufacturers must certify their products; accordingly, for each window model, the exact heat transfer resistance coefficient is calculated, which determines its energy efficiency.

Heat insulation

Thermal insulation can be improved by using an air chamber and a heat-reflecting layer (for example, silver) applied to the surface.
This principle is most easily explained by the example of a thermos: the metalized walls of the flask reflect heat, and the air chamber around the flask reduces heat loss and maintains the temperature inside. In a double-glazed window, it is enough to apply the thinnest layer of a substance to the surface of the glass to increase its heat-reflective ability.

Sliding warm glazing

Sliding glazing is often used on balconies and loggias, as well as on verandas, allowing for the most efficient use of the available space. In this case, the frames do not swing open, but move relative to each other. Such glazing can be cold (aluminum) or warm (using a plastic profile). If the glazed room is planned to be heated and used as a living space, you cannot do without warm glazing, although it is more expensive.

Sliding systems based on aluminum profiles can also have a thermal insert; such systems can be used for warm glazing and are not inferior in energy efficiency to plastic double-glazed windows.

One of the best solutions for warm sliding glazing is the SLIDORS PVC system. These systems are made of PVC profiles with galvanized reinforcement inside; double-glazed windows use a double seal with a special insert. Double-glazed windows combine high strength with excellent heat and sound insulation characteristics, are waterproof, and thanks to the high rail can be used in any weather. Sliding systems based on PVC profiles are more affordable than swing systems.

For warm sliding glazing, you can use the KBE PremiLine system, provided that energy-saving double-glazed windows are installed. The LG Hausys system with 18 mm thick glass units is also used for warm sliding glazing.

Transparent heat-reflecting glass

The difficulty in applying a heat-reflecting layer to glass lies in choosing the optimal light-transmitting material with high heat-reflective ability.

I-glass

A coating (soft spraying) applied to the glass surface using a magnetron method is designated LowE (Low Emission) or the Russian letter I.

Soft low-emission coating is so named due to its instability to any influences: mechanical, as well as the effects of atmospheric moisture and air, which oxidize silver. The coating loses its emissive properties and transparency. This gives rise to special requirements for the tightness of double-glazed windows during production.

K-glass

Low-e glass with a so-called hard coating, which is applied by pyrolysis in a hot furnace during the production of the glass itself, does not have the above-described disadvantages. In this case, the low-emission coating is laminated on top with the molecules of the glass itself and is not even subject to mechanical abrasion. Such a “hard” low-emission coating in the glass unit formula is designated by the Russian letter K. Its disadvantages include lower heat reflectivity and the cost of the production process.

Highly selective glass: energy saving and multifunctionality

As you can see, low-emission “I” and “K” glasses cope well with the task of reflecting infrared thermal radiation from heating devices, but are not able to fully cope with the reflection of excessive solar heat in the summer.

Highly selective glasses were able to cope with this task. Thanks to the application of several different molecular compositions, the glass receives, in addition to the function of reflecting infrared radiation (as in a heat-saving package), the function of reflecting warm solar waves. With such glass, the window copes better not only with frost, but also with the scorching rays of the sun, reflecting them.

Disadvantages of the material

Energy-saving film is not a source of heat and does not affect the heating of the room. Retains heat produced by central heating sources. The material maintains the existing air temperature.

Through a window covered with athermal protection, heat from the street does not penetrate

Disadvantages of the material:

1. The protection does not allow UV radiation to pass through and is not recommended for use in rooms with indoor plants. Not suitable for tinting glass in greenhouses and greenhouses in the local area. Plants need ultraviolet light to grow. If there are plants in a room with energy-saving coating, you can use phytolamps. However, you can forget about saving energy - for normal plant growth and compensation for the lack of sunlight, lighting must work at least 12 hours a day.
2. The effectiveness of the film coating depends on proper gluing. It is better not to cover large areas of glazing - for example, panoramic windows or portals - by yourself.
3. The coating prevents the penetration of natural solar heat from outside into the room; in spring and autumn the apartment will be uncomfortable - damp, cold. Mobile heating devices must be turned on.
4. Ability to reflect radio signals. Radio waves from the outside going to the indoor antenna or mobile phone are reflected by the coating. There may be interruptions in cellular communications.
5. If the room has window systems with two or three-chamber double-glazed windows, it is not necessary to use film.

Heat-saving double-glazed windows

Mandatory design elements of a heat-saving double-glazed window:

• Low-emissivity glass (one - in a single-chamber double-glazed window, up to two - in a double-glazed window),
• Plastic spacer (to eliminate cold bridge),
• Inert gas in the air chamber of a glass unit.

Thanks to this combination of elements, it is possible to achieve high thermal insulation properties.

Warm frame in double glazing

If sufficient thermal insulation is not provided in the edge zones of double-glazed windows, the window freezes, becomes covered with frost, warm air leaves the room through it, and cold air penetrates inside. When traditional aluminum dividing frames are used in the construction of double-glazed windows, this problem occurs quite often.

Stainless steel frames improve the thermal properties of the glass unit. But the best thermal insulation properties are possessed by the so-called warm frames of the warm edge system, for the manufacture of which fiberglass, plastic, silicone and similar polymer materials are used.

Read about other types of spacers here.

The material of warm frames is durable and does not lose its performance characteristics when exposed to sunlight, and is not afraid of humidity. The thermal conductivity of warm frames is significantly lower than that of aluminum frames, therefore, the thermal insulation characteristics are higher. In practice, double-glazed windows with a warm frame (warm edge) have the following advantages over windows with an aluminum separating frame:

• in winter, the temperature of the edge zones of the window increases by 5-6%;
• the formation of condensation, mold, and frost in winter is prevented;
• there are no places in the design that are vulnerable to the penetration of cold from the outside;
• heat loss through the window is reduced, the heat transfer coefficient into the room reaches 70%.

Energy-saving double-glazed windows

Mandatory design elements of an energy-saving double-glazed window:

• Multifunctional glass (one - in a single-chamber double-glazed window, and in combination with low-emission glass - in a double-glazed window),
• Plastic spacer (to eliminate cold bridge),
• Inert gas in the air chamber of a glass unit.

In addition to insulating the thermal radiation of the infrared spectrum, an energy-saving or “multifunctional” double-glazed window cuts off solar heat flow and ultraviolet radiation.

Panoramic warm glazing

Panoramic (from floor to ceiling) glazing is good because it allows maximum light into the room. On the other hand, an increase in glazing area can lead to an increase in heat loss in winter. Therefore, it is important to use double-glazed windows, rather than single-glazed windows, for warm panoramic glazing, with the best thermal insulation characteristics. For these purposes, it is worth choosing double-glazed windows with chambers filled with argon, low-emission glass coating and a warm separating frame.

For warm panoramic glazing, it is preferable not to massive PVC packages, but to lighter double-glazed windows based on an aluminum profile with a plastic thermal insert. SunFlex designs (Germany) are ideal; this is a folding system that allows you to glaze openings of various configurations up to 3.5 m in height and provide threshold-free glazing. The design is characterized by low thermal conductivity and high noise insulation properties; each leaf has a double sealing circuit. The system can be aluminum or wood-aluminium, and has aesthetic appeal.

The heat-saving characteristics of a window depend on a number of parameters - the thickness and number of glasses, the thickness of the chambers and their filling, the material of the dividing frame, the presence of a heat-reflecting coating and the technology of its application. The heat-saving properties of the window are increased by filling the chambers with argon, using a polymer dividing frame, and low-emissivity spraying on the glass. The most effective windows are those that combine several heat-saving parameters.

Price

The cost of a double-glazed window depends directly on the constituent elements. Due to the complexity of the production process, a multifunctional energy-saving double-glazed window is more expensive than a heat-saving one.

Detailed price list in the section prices for double-glazed windows.

You can order the production of heat-saving or energy-saving double-glazed windows according to your dimensions by contacting the Business-M company.

Construction or installation depth of the window

In fact, the construction (installation) depth of the window is the thickness of the profile, and the larger it is, the warmer the translucent structure will be. The construction depth of the profile is most often at least 70 mm, but in many European countries, where heating prices are higher and, accordingly, energy efficiency requirements are stricter, it reaches 85-90 mm. At the same time, structures with even greater widths are used for glazing passive houses.

It is important to understand that with the same building depth, different models of window profiles may have different energy efficiency indicators - it all depends on how rationally the air space inside the double-glazed window is used.

Window technologies are constantly evolving, so most often new window models have better heat-saving qualities than old ones of the same thickness. It is also worth considering that the products of large companies, which have the opportunity to spend more on design, often surpass in energy efficiency the products of small companies that are similar at first glance. An excellent example is the SCHTERN FEST profile system, which at the international construction exhibition BATIMAT RUSSIA 2014 received first place in the “Efficiency” category.

In what cases is it advisable to use heat-saving film?

Heat-saving film is recommended to be used in the following cases:

1. if it is necessary to significantly increase the heat level without using energy-consuming and air-drying heaters;
2. if it is necessary to significantly reduce the heat level without using air conditioners, which tend to accumulate pathogenic bacteria in their filters;
3. if an old double-glazed window is installed in the room, which has significant thermal insulation flaws: gaps between the frame and the wall, between the frame and the glass;
4. if the room has large window openings that occupy almost the entire wall space;
5. if you need to protect the room from sudden temperature changes that are typical for most of our country;
6. if you need to protect the decoration of the room from exposure to ultraviolet sunlight, that is, from fading, which is especially necessary for walls, furniture, and antiques.

Thus, the scope of use of heat-saving film is quite wide, and this type of product is gaining popularity due to its availability and relative ease of installation.

Window seals

The energy efficiency of window structures is increased through sealing systems. There are two main ways to do them. The first is the sealing of the rebate (a sealing strip of rubber or silicone is placed on the frame). The second is the so-called middle seal (when the sealing elements are located on the sash, closer to its central part).

To ensure that window seals do not dry out for a long time and retain heat, they must be cleaned of dirt and lubricated with special products.

The second option allows for better heat retention, so it is used for systems with increased energy efficiency requirements. In addition, medium sealing is recommended for windows of houses located in mountainous and coastal regions characterized by strong winds. The most reliable protection against blowing is provided by the combined use of both sealing systems.

Advantages and disadvantages

The pros and cons of energy-saving windows are obvious. The obvious advantages include the following points.

1. Preservation of indoor microclimate at any time of the year. It works on the principle of a thermos - it prevents heat loss in winter, and protects from heat in summer.
2. Increased heat and sound insulation. The gas layer additionally absorbs noise.
3. Protection against fading of interior parts.
4. A light weight. With the same characteristics, a single-chamber double-glazed window weighs less than a standard double-chamber one.
5. No condensation. There is no temperature difference causing fogging.
6. Budget savings by reducing energy consumption.

The first drawback is the price. The cost is 5-10% higher compared to conventional blocks. But the difference will pay off quickly due to savings on utility bills for heating and electricity.

It is unknown how long the coating will last. Metal spraying oxidizes when interacting with oxygen. If the product is defective or the seal is broken, rainbow stains will soon appear on the inner surface of the glass and all valuable properties will be lost.

Storing glass with a soft i-coating without packaging for more than a month also leads to the appearance of rainbow stains. Unscrupulous manufacturers are trying to use expired components. Therefore, if the glass package you are installing contains rainbow-colored glass, you should immediately discard it.

There is an opinion that the products are harmful to flowers because they reflect sunlight. This is a mistake; the spectrum necessary for plant photosynthesis passes through unhindered.

They transmit less light due to the coating. For the eyes, a difference of 5% is almost imperceptible, but it can be recorded with a special device.

Correct installation of windows

The percentage of windows installed in accordance with the technology is negligible. For high-quality installation, it is necessary to involve highly qualified specialists, whose work, compared to the services of ordinary craftsmen, is more expensive, especially when it comes to installing windows in winter. In addition, purchasing professional materials for installation also requires costs that many developers do not want to incur. However, it should be remembered that saving in this case leads to a loss of energy efficiency of the structure, and in some cases can lead to the complete absence of any positive effects.

It is better to order window structures and their installation from authorized partners of large window profile manufacturers

An important step that is almost always missed when installing windows is protecting the installation seam with vapor and waterproofing. The first is placed on the inside of the room to prevent moisture from penetrating into the foam insulation. The second is mounted on the street side to protect it from precipitation. If these important elements are neglected, the foam will become saturated with moisture, which at low temperatures turns into ice and destroys the structure of the insulation. As a result, the installation seam will begin to allow cold to pass through. Warm glazing of the loggia and balcony. Secrets of choosing and installing PVC windows for a balcony:

If it is not possible to arrange professional hydro- and vapor barrier, you need to protect the insulation with at least an ordinary liquid vapor-permeable sealant. To do this, one day after installation, you need to carefully cut off the foam and, using a brush, apply one layer of sealant on the outside of the seam and two layers on the inside. When applied again, the material loses its vapor-permeable qualities and blocks the penetration of moisture from the room into the insulation. Vapor and waterproofing of assembly seams is necessary to protect against blowing and destruction of foam seams.

After processing, the seam is plastered. At this stage, another mistake is made, leading to heat loss. Most often, the slope is brought close to the window, which cannot be done. The profile heats up more than the plaster, and the thermal expansion of the material over time leads to the formation of cracks at the contact point. To avoid this, it is necessary to use abutment profiles, which are offered by all reputable manufacturers of plaster mixtures.

I recommend viewing. A very detailed and very useful video about PVC slopes for plastic windows and finishing secrets:

What are they?

Poor thermal insulation of apartments is a fairly common problem. Experts have proven that about 35% of room heat escapes through windows. Heat loss almost doubles heating bills. Thanks to the technology features, energy-saving windows help keep the house warm.

Products consist of:

• Frames made of polymer with low thermal conductivity;
• Double-glazed windows with spraying, heat-reflecting film or inert gas;
• High quality fittings.

Each component part of the block: fittings, double-glazed windows, frame are energy efficient. All together they represent high-tech products of a new generation.