Summer is over, it's time for warmth, and with it autumn and preparations for the heating season have begun. Very soon the batteries will turn on, as well as electric fireplaces and gas heaters, which consume hot water, gas and electricity in large quantities. In connection with this situation, the question arises related to reducing the cost of heating rooms, and one of the most practical and cheapest solutions is to replace conventional windows with heat-saving ones. The energy and financial savings when using these windows are obvious: when using them, heat exchange with the external environment is reduced by 70%, which leads to similar reductions in heat loss, and, of course, your money!
Double-glazed windows STIS - Winner of the “SAVE ENERGY” Award
What are heat-saving windows?
What are heat-saving windows? These are ordinary windows with special glass as part of double-glazed windows, covered with a very thin layer of metal, which practically does not allow heat to pass through - that is, in winter the apartment will be warm, and in summer it will be cool, while ordinary glass practically does not retain it. Another major advantage of this type of window is that it prevents furniture, wallpaper and carpets from fading, that is, over time they will not lose their color and brightness due to the sun! These windows also differ in the type of coating: hard coating, used in single glazing without double-glazed windows (for example, when glazing balconies, loggias, etc.), and soft coating, which is universal in nature, because it has higher thermal insulation parameters and used only as part of a double-glazed window.
Glass-composite profile + double-glazed window: the ideal formula for a warm window
Also, one of the most significant advantages of heat-saving windows is that they are much lighter and stronger than their glass counterparts, which not only makes them easier to use, but also significantly increases durability due to the use of alloys and composites in them.
Thus, the advantages of energy-saving double-glazed windows are obvious, and if you want to get the optimal combination of price and quality, you can safely order them and calmly welcome the heating season.
One of the best options in terms of the listed operational characteristics can be called a universal window system - STIS™ Thermal Packages, which, with proper options, are ideal for all regions of Russia in any climatic conditions.
Our company, at the request of the customer, will install such double-glazed windows both in warm sliding doors and in any swing structures.
Our large country is located in different climatic zones. This causes differences in the requirements for thermal insulation of windows in different regions. However, despite this, heat-reflecting double-glazed windows have proven to be in demand literally in every corner of the country. The appropriate question is - why? It can only be answered by thoroughly understanding what the peculiarity of these products is, what their advantages are, and whether they have any disadvantages.
Heat saving efficiency of heat-reflecting double-glazed windows
First of all, it should be noted the versatility of heat-reflecting double-glazed windows. They can be used anywhere without any restrictions. In a residential building, office, shopping and entertainment establishment - everywhere, heat-reflecting windows will ensure a comfortable room temperature. Double-glazed windows with heat reflection function are much more efficient than conventional windows with three glasses. The latter are designed to reduce convective heat loss, while 70% of all heat loss occurs through infrared radiation. The peculiarity of heat-reflecting glass is that they reflect infrared radiation, directing it back into the room. Experts say that the most effective way to reduce heat loss is to increase the heat-reflecting properties of windows.
If we compare heat-reflecting double-glazed windows with conventional double-chamber ones, it turns out that in terms of ease of use and heat reflection characteristics they are significantly superior to conventional ones. They are significantly lighter in weight than double-glazed windows and therefore easier to install. But, most importantly, they reflect infrared radiation much more effectively, which can greatly reduce heat loss from the building. If your main goal when purchasing windows is heat conservation, you need double-glazed windows with heat reflection.
Manufacturing technology of heat-reflecting double-glazed windows
Let's talk about the intricacies of the technologies that are used in the production of heat-reflecting double-glazed windows. Heat is reflected not by the glass itself, but by a special coating applied to it. There are two types of coatings that fundamentally differ from each other in performance characteristics. One of them is called “soft”, the other is called “hard”.
The “soft” coating is two-layer. The first layer is a silver coating that reflects IR rays, the second is titanium oxide. The combination of these two layers is considered the most effective in terms of heat reflection. Tests have shown that double-chamber double-glazed windows with a “hard” coating retain heat worse than single-chamber double-glazed windows with a “soft” coating.
The technology for applying a “hard” coating is quite labor-intensive. The glass is first heated to the required temperature, and then, when it is hot, a metallized coating is applied. Glass molecules have a crystalline structure. This allows metal particles to penetrate into the glass, resulting in the formation of a heat-reflecting film, on which a thin layer of glass is applied on top to protect it and increase its service life.
Currently, double-glazed windows with a “soft” coating are becoming increasingly popular due to their advantages, which deserve special mention.
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.
Disadvantages of heat-reflecting double-glazed windows
It is important for a person who has decided to install PVC windows to determine what exactly he wants to get from installing these windows: simply install a modern, beautiful window or protect his home from noise, cold and solar overheating.
If you choose the latter, then the best option is to install windows with energy-saving glass.
What is heat-saving (energy-saving) glass? These are glasses on which special ultra-thin, completely transparent low-emission coatings are applied. Low-emission coatings transmit short-wave radiation and do not transmit long-wave radiation. In other words, they transmit sunlight well into the room and poorly transmit heat emanating from heating devices, as a result of which warm air remains in the room and does not escape through the glass to the outside. This significantly reduces the cost of heating the room and saves significant money.
Energy-saving glass, according to its technology and efficiency, is divided into K-glass and I-glass.
1. K-glass is produced using pyrolytic technology with a durable hard coating (metallic). The technology for producing K-glass involves applying a coating to the glass during its manufacturing process. Metal oxides are sprayed onto the glass at a temperature of about 600 degrees. At such a high temperature, metal oxides penetrate into the glass structure itself, becoming one with the glass.
In appearance, K-glass has no differences from ordinary glass.
K-glass significantly reduces heat loss. It transmits short-wave solar energy into the room and does not allow long-wave heat radiation from heating devices to pass out. The disadvantages of K-glass include its lower efficiency compared to I-glass and its high price.
K-glass can be tempered and laminated. Glass is tempered by chemical or thermal treatment, which increases the strength of the glass to various types of impacts and temperature changes. Laminated glass is two or more glasses connected to each other by a special film or a special liquid.
2. I-glass is produced using magnetor technology with a soft coating. This technology consists of applying tiny particles of metal oxides to glass by electromagnetic sputtering in a vacuum environment.
The disadvantage of I-glass is its abrasive fragility, which affects transportation and storage. After opening the package, such glass must be installed immediately, so mainly specialized companies work with such glass. But the thermal insulation properties of I-glass are much higher than those of K-glass, and its price is lower.
Main misconceptions about heat-saving glass:
1. Heat-saving glasses have a short service life.
Not true. The heat-saving coating cannot be damaged during operation of the window, since it is located inside a sealed glass unit. Its service life is equal to the service life of the window.
2. Heat-saving glass does not transmit ultraviolet light.
Not true. PVB film, which is glued to windows, does not transmit ultraviolet radiation.
3. Heat-saving glass has a bad effect on indoor plants.
Not true. Plants need visible light, and heat-saving glass allows sunlight to pass through perfectly and, in addition, creates a microclimate that is so necessary for indoor plants.
4. Heat-saving glass will make it hotter in summer.
Not true. Through heat-saving glass, the room heats up 12% less in summer than through conventional glass.
Heat-saving double-glazed windows are double-glazed windows using heat-saving glass: K-glass and i-glass(sputtered glass)
K-glass (hard coated glass)
A pyrolytic float glass manufacturing process in which metal oxides are deposited during the glass manufacturing process (i.e., onto the hot glass). The coating of this glass is hard, durable, neutral in color, and has low-emission properties.
Advantages:
- good thermal insulation properties (Ro = 0.58 m2K/W)
- reduction of heat loss in winter
- high light transmission
- neutral color in transmitted and reflected light
- hard and durable pyrolytic coating
- can be subjected to the following processing: bending, lamination and hardening
i-glass (soft coated glass)
High-quality glass with a low-emissivity coating applied to one surface of the glass using vacuum magnetron sputtering. The coating, which has the properties of a light filter, is transparent to the human eye, transmits sunlight well and reflects thermal radiation back into the room. It consists of several thin layers containing silver, the choice of which depends on the required characteristics of the glazing: emissivity, light transmission, as well as optical properties - removing unwanted reflections.
Advantages:
- maximum energy saving characteristics
- has high light transmittance
- has low reflectivity
- reduction of internal condensation
Heat-saving glass
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Hard surface |
Soft cover |
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Emissivity (emissivity - the ability to reflect heat back into the room) |
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Solar transmittance (maximum=1) |
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Shelf life |
Unlimited |
9 months after production |
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Coating strength |
Like regular glass |
Requires careful handling - easily damaged |
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Processing-hardening |
Easily tempered (not a little longer than regular glass) |
Only when using special equipment and procedures |
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Glass processing |
Like regular glass |
Edge removal required |
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Transportation |
Like regular glass |
High risk of surface scratches |
The low-emissivity coating has a very high electron density of atoms. Long-wave radiation (heat emitted indoors by heating devices, central heating, light bulbs and even human body temperature) cannot fully pass through the coating, mostly being reflected back into the room. Short-wave energy (solar energy) effectively passes through low-e glass, accumulates and turns into long-wave energy, thereby providing an additional source of heat and effective insulation.
The use of heat-saving glass can reduce energy losses by approximately 70%.
Due to the growing consumption of double-glazed windows with heat- and energy-saving glass, since January 2009, the STiS Group of Companies introduced additional marking of double-glazed windows containing “warm” low-emissivity glass with a “soft” coating with a holographic sticker of the following type:
The holographic sticker is applied to glass with a low-emissivity coating on the outside of the glass.
No matter how excellent the thermal insulation properties of the profile may be, the main heat loss occurs through the double-glazed window, so special attention should be paid to its selection.
Energy-saving windows, what is it?
A feature of windows with an energy-saving function is the ability to reflect heat waves emanating from heated objects back into the room, significantly reducing the percentage of heat loss. This effect is achieved due to the presence of glass with a low-emissivity coating in the glass unit. Today there are two types of such coating - hard (k-glass) and soft (i-glass). The latter is more popular due to its higher energy-saving characteristics. In the production of k-glass, tin oxides are used, and i-glass is made by depositing silver oxides. Since i-glass can quickly collapse from mechanical or atmospheric influences, it is placed directly into a double-glazed window.
The effectiveness of energy-saving windows is evidenced by the fact that a double-glazed window with i-glass, even with one chamber, has a higher coefficient of heat transfer resistance than a conventional double-glazed window, and the cost of such a window will be lower.
The main advantages of energy-saving windows are:
- high thermal insulation rate due to the reflection of thermal radiation back into the room;
- significant savings on space heating;
- preventing things from fading;
- lower weight of the sash with a single-chamber energy-saving double-glazed window and, at the same time, better thermal insulation compared to a conventional two-chamber double-glazed window.
What are energy-saving windows made of?
1. Energy-saving double-glazed window
Double-glazed glass is a key part of an energy-efficient window. Heat-saving double-glazed windows contain glass with a low-emission coating (i-glass) which is coated with a layer of silver ions, reflecting heat back into the room. The presence of such double-glazed windows in combination with a good profile and fittings allows you to make the house as warm as possible.
2. Profiles of various types
The profile most often used for the production of heat-saving windows is the profile of the German companies Rehau and KBE, which have gained popularity all over the world. Energy-saving windows Rehau and KBE will have high levels of thermal insulation and reliability. Those who prefer products from domestic manufacturers and seek to find the optimal combination of cost and quality should pay attention to the Novotex profile. For connoisseurs of natural materials, windows made of pine, larch or oak wood, which are highly durable and can last for a long time, are suitable. For the production of large-sized structures, a profile made of warm aluminum with thermal inserts from the manufacturers Alutech and NewTec is used.
3. Accessories
Reliable fittings will help maintain a good seal of the window and will not allow cold air to enter the room, reducing the cost of heating the entire house. Fittings from German manufacturers Roto or Siegenia Aubi have proven themselves to be highly reliable and are designed for more than 40,000 window opening cycles.
Technical characteristics of double-glazed windows with energy-saving i-glass
| Single chamber | Single chamber energy saving | Double chamber | Double chamber energy saving |
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Double-glazed window formula |
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| 4-16-4 | 4-10-4-10-4 | 4-10-4-10-4i | |
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Glazing thickness |
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| 24 | 32 | 32 | |
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Heat transfer resistance, m2°C/W |
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| 0,32 | 0,49 | 0,61 | |
| Sound insulation, dB | |||
| 24 | 24 | 37 | 37 |
| Sash weight, kg/m2 | |||
| 20 | 20 | 30 | 30 |
How to decorate heat-saving windows?
For this purpose, various decorative elements are used, and through lamination, plastic windows can acquire any color required by the customer or be made to look like wood.
| Stained glass | Profile lamination | Double-glazed window tinting | Window layouts |
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The decorative layout or strips can be attached both inside the double-glazed window and on the outside. Shprosses can visually divide a large window into several parts. Tinting not only helps to give the glass unit, and, consequently, the window, an unusual look, but also protects it from both prying eyes and bright sunlight. Double-glazed windows with stained glass windows will be beautiful and unusual. You can order an expensive type of stained glass - classic or Tiffany, or you can order a decorative film with a pattern glued inside the glass unit - it all depends on the financial capabilities and desires of the customer.
4 reasons to buy energy-saving windows from REHAUpartner
The REHAUpartner company offers a wide range of products for glazing any objects at an affordable cost. All products are manufactured in automated production, which ensures high quality products and completely eliminates the “human factor”.