The installation of energy-saving glass helps to enhance thermal protection and save energy resources through glazing. There are several ways to determine which glass is in a double-glazed unit. In the European Union, such filling for windows is installed by default - in accordance with building codes. In Russia, the trend is only gaining momentum. Not everyone takes the stories of experts about its effectiveness, but more and more homeowners are convinced that the thermally efficient coating performs its stated functions. Find out how to check an energy-saving double-glazed window for the presence of coating with special properties.
Energy-saving windows: myths and reality
Despite the popularity of energy-saving windows, there is also skepticism towards them. However, in practice it has already been confirmed that they very effectively maintain normal temperature in the house. The high cost is offset by savings on heating. According to numerous customer reviews, it is known that in addition to saving energy resources, “warm” windows also eliminate other problems.
Advantages of energy-saving double-glazed windows:
- maintaining heat in the room during the heating season;
- ensuring coolness in the room during the summer heat;
- protection against condensation formation;
- UV protection;
- You can install lighter single-chamber double-glazed windows, which are not inferior to conventional double-chamber products in their heat retention properties.
Energy-saving windows have plastic double-glazed windows with a special modification that prevent heat exchange between the street and the room. This helps you spend less money on heating during the cold season. This is especially important for owners of private houses. In multi-apartment buildings where the heat supply is not regulated, the benefits include maintaining heat in winter, as well as coolness in the summer heat. After all, such windows do not allow the air in the room to heat up, even when the temperature outside is very high.
Another big advantage of such windows is the reduction in the likelihood of condensation. After all, two factors contribute to the formation of droplets on glass - high air humidity and a cold surface. Energy-saving double-glazed windows allow you to maintain a higher glass temperature on the room side. Therefore, condensation can very rarely appear on it.
These windows also protect indoor surfaces from fading due to exposure to sunlight. Furniture, textiles, paintings and other interior items retain their original color for a long time, even if the room is located on the sunny side.
The protective barrier limits the penetration of ultraviolet rays from outside into the house. But this does not in any way affect the growth and development of indoor plants, because the flowers receive a sufficient level of 35% UV radiation.
Single-chamber energy-saving double-glazed windows can be 20% more efficient than conventional double-chamber ones. Two-chamber and three-chamber ones, manufactured using new and improved technology, have even greater thermal insulation properties.
But the advantages and use of such single-chamber windows are irreplaceable where the design of the house does not allow significantly heavier weight loads. Lightweight single-chamber products in such cases fully replace conventional PVC windows with multi-chamber double-glazed windows.
The most common myths about energy-saving windows and their refutations:
- The inert gas argon, which fills the sealed spaces inside double-glazed windows, quickly evaporates. This myth is spread by competitors. This is done to promote their products on the market.
- There is no argon inside the double-glazed windows - this is an advertising gimmick. The presence of this gas cannot be visually determined because it is invisible and odorless. But testing methods are used to check for the presence of argon. For example, if you bring a lit match close to glass, then if there is argon inside, the color of the match flame and its reflection will be different.
- Plants die in a room with such windows. In practice, it has already been verified that plants grow well in such rooms. They receive a sufficient dose of ultraviolet radiation necessary for growth and development. And also, reliably protected from the cold in winter. When simple PVC windows are installed, the flowers on the windowsills freeze.
- There are no energy-saving double-glazed windows. But these products are being produced. Their thermal insulation properties have been tested during operation.
Marking
Basic information about the technical parameters is indicated in the documentation and sometimes on the spacer frame in the form of a marking (formula), which contains information about the number of glasses, their thickness, the distance between the glasses, the type of gas filling and the presence of additional coatings. The marking of a single-chamber energy-saving double-glazed window according to GOST 24866-2014 may look like this: 4M1-Ar10-I4. Where:
- 4M1 - thickness 4 mm, glass grade - M1;
- Ar10 - argon gas filling, distance between glasses 10 mm;
- I4 - low-emissivity glass with a “soft” coating 4 mm thick.
“Hard” coating is designated by the letter “K”. When using dried air, the type of gas filling is not specified.
Energy-saving glass in a double-glazed window
In appearance they do not differ from ordinary PVC windows. They are single-chamber or multi-chamber packages with several glass surfaces and connecting partitions with seals. Inside the chambers, the space is filled with an inert gas, often argon. This improves thermal insulation properties and additionally sound insulation.
Even before assembly into bags, the surfaces of the glass inside the chambers are coated with a special coating of a layer with silver ions or indium and tin oxides. The technology of two-layer coating of silver and titanium is also used. Depending on the type of spraying on windows, the technical characteristics of the surface’s resistance to chemical and physical influences differ.
Sprayed coatings are applied in a thin layer (0.08-0.12 microns thick), which is invisible to the human eye. If the manufacturer has not done such a coating, then purchase a special protective film and apply it on both outer sides of the glass. Clear and tinted protective films are available for sale.
This technology made it possible to embody the following properties in one material:
- energy saving;
- heat-saving;
- shockproof;
- protective against ultraviolet radiation from outside and infrared rays from inside the room;
- self-cleaning surfaces.
The technology for their manufacture is complex. It requires the use of expensive modern equipment. Such acquisitions are available only to large manufacturing companies. Strict adherence to all stages of the technological process is necessary. It is impossible to make these products in artisanal conditions.
It is difficult for an untrained person to visually distinguish a double-glazed window with energy-saving properties from a regular one. It is better to choose products from well-known large companies.
Be sure to check the appropriate labeling. This will allow you to purchase a quality product with a guarantee.
Testing devices
Imported.
The market offers devices from foreign manufacturers, mainly from the USA and Germany, which have proven themselves well in practice. Depending on the functionality and the availability of additional measuring functions, they cost from 100 to 800 euros. Their use in serious production can be economically feasible. But why do they need a person who is not going to check double-glazed windows every day? Because of their price, imported devices are not widely used in our country.
Device ODA-1000
The NPO DiOD company offers a device of its own design. It has undergone a full cycle of testing, as well as certification by the Glass Institute, which confirmed its reliable operation on all types of low-e and multifunctional coatings.
The operating principle of the device is based on determining the electrical characteristics of the surface. The thickness of the glass being tested can range from 4 to 12 mm, and the presence of coating on both the front and back sides of the glass is guaranteed. The influence of the human factor is completely eliminated - the results are indicated by one of three LEDs and duplicated by an audio signal. The verification time does not exceed a few seconds. The kit includes a fabric protective case and a power supply.
Disadvantages of energy saving packages
There are pros and cons to these products. The biggest disadvantages include the high cost. Because the manufacturing process is complex. But as a result, over time of operation, such costs are justified by saving energy resources and creating more comfortable conditions in the room.
In some cases, when the protective layer was poorly sprayed during the production process or the seal of the glass unit was broken, its energy-saving properties are lost. When purchasing, it is difficult to immediately determine their quality. But well-known manufacturing companies value their reputation. They test their products for defects. Therefore, their products can be purchased without fear and with a guarantee.
If heat-protective windows are installed on the sunny side, this significantly reduces their service life with high-quality protective properties. The PVC windows themselves will last a long time, but their thermal insulation properties will be much reduced. The lowest service life when using a protective film is that after 10 years it will lose its useful functions.
Advantages of technology
Heat-saving double-glazed windows have a number of obvious advantages:
- High-quality heat insulation, due to which you can significantly save on heating or air conditioning.
- The design has less weight compared to conventional windows.
- Condensation does not form on the surface of the windows.
- Metal spraying protects the structure from burning out in a fire, making it safer.
- Glass allows you to control the heat balance in the room at any time of the year.
- Due to the small size of the glass unit, the service life of the fittings increases by an average of 30%.
- Thanks to the special coating, infrared and ultraviolet radiation is delayed and enters the room in significantly smaller quantities, which has a positive effect on people’s health. The same property helps protect wallpaper, paintings, and furniture from premature fading.
- Energy-saving glass in plastic windows allows you to retain 25% more heat than conventional windows with double-glazed windows can do.
If your windows face a noisy avenue, it is recommended to choose a design equipped with three glasses. In this way, it will be possible to achieve high-quality sound isolation.
How to distinguish an energy-saving package from a regular one
It is visually difficult to distinguish between regular and energy-saving double-glazed windows. Therefore, when choosing, you need to check the product labeling. For example, for a regular similar product it will be 4-16-3, and for the same heat-protective product with argon in the chambers it will be 4-16-Ar-4I.
Decoding the labeling of an energy-saving package in this example means that it is two-chamber with a sheet thickness of 4 mm, argon gas is inside the chambers, and an energy-saving I-coating is applied to one of the glasses.
Special devices can accurately determine the properties of energy-saving double-glazed windows - the thickness of the glass, the type of protective coating, and can even derive the formula of the product. But few people have access to such devices. They are usually used in large construction companies to monitor the quality of materials and work performed on glazing objects.
Available verification methods:
- When going to the store, you need to take a lighter or matches with you. If you bring a flame close to the glass, its reflection in a regular double-glazed window will not change, but if there is argon gas inside, then the reflection of the flame will be more reddish.
- Another way to check energy-saving glass of double-glazed windows is the “flare method”. If you look at the glass at an angle, then on its surface, if it is an energy-saving product, you can see a bluish-violet tint.
Control methods
How can you make sure that the glass unit delivered to you matches what you ordered? There are several simple ways.
Label on the glass unit
You can start by examining the tag on the glass unit. It should indicate the main characteristics: what kind of double-glazed window it is - single-chamber or double-chamber, the size of the double-glazed window, the thickness of the glass and the width of the spacer frames, whether there is spraying on the glass or not, whether there is multifunctionality and an inert gas (argon). For example, 6Selekt-10Ar-4F-6Ar-4i.
From this designation it is clear that there are three glasses, the first of which is 6 mm thick and multifunctional (besides the letter S, there may be others). Next comes a 10 mm wide spacer frame separating the glass, and this space is filled with argon.
In the middle of the two-chamber package there is ordinary float glass 4 mm thick. Then there is a 6 mm wide chamber with argon. And the third 4 mm glass has i-spraying. Unfortunately, the tag is not a 100% guarantee. Therefore, let's consider other control methods.
Open fire test
You can use a lit candle or lighter as an indicator. If we bring it to a regular double-glazed window, we will see three absolutely identical (in terms of the number of glasses in the package) reflections.
But, if the double-glazed window is energy-saving, these reflections will differ in color shades. For example, for the first i-glass the reflection tint can be pink, for the last multifunctional one it can be purple, and the average reflection on ordinary glass can have a natural appearance.
Checking with a thermal imager
This verification method is the most informative. If you point the device at a regular window, you can see that the warm air in the double-glazed window, according to the laws of physics, has risen upward, forming a heat zone. Cold air, on the contrary, created a cold area below near the windowsill.
If a regular aluminum spacer is installed in the window, this will also be clearly visible, since it will be one of the coldest elements.
When examining an energy-saving package with a thermal imager, a completely different picture will be observed. You won't see any warm or cold areas. The surface of the glass will be heated evenly over all surfaces, and will have a temperature 5-8 degrees higher than a conventional double-glazed window.
Which side to install energy-saving double-glazed windows
For the correct functioning of the double-glazed window, you must follow the installation rules. Then the protective films will fulfill their purpose. Most are applied inside the chambers to protect these coatings from oxidation and damage.
Surfaces with a self-cleaning effect, hard glass, multifunctional and designed to reflect sunlight from the surface are always placed on the street side.
Low-emission coatings should be located either inside the chambers or on the side of the room. Because their main function is to preserve long-wave infrared radiation and prevent heat loss from the room.
Thermophysical explanation
Someone will rightly note that not even three years have passed since I changed the windows, but they are no longer relevant, they are not the best. What now, as soon as a new product has appeared, should you immediately spend money on it? I’ll buy a film to save heat and that’s it. Although not an ideal option, it has the right to life.
Let's take a look at how thermal physics is integrated into the design of the new product. Maybe this will convince, the person will decide for himself whether it is necessary to change or not, whether the new product is worth the money or not. Moreover, let us remind you that classical wall insulation technologies are not applicable for window openings. But the advantage of new window systems is that by reducing heat leakage, the manufacturer increases the access to light.
Let's return to the physical explanation. Thermal energy travels either in the form of radiation or convection.
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Radiation - infrared spectrum, is determined by the level of surface heating. Convection is the exchange of heat between hot and cold.
Simple glass does not interfere with the infrared ray, that is, you can stick a film on it, it will reduce the release of hot heat to the street. When making energy-saving bags, at the production stage the glass is coated with non-ferrous metal sulfide and silver plating is done. They can apply a film.
The treated surface increases the level of reflection of infrared radiation by 80%. The treated glass surface transmits 72% of light, the remaining 28% does not affect perception. In summer, the surface will reflect up to 45% of solar radiation.
Window energy efficiency class
Everyone is accustomed to seeing stickers on household appliances with a scale of their energy efficiency indicators. The same information also applies to double-glazed windows. They mean how much products of this marking allow you to save on heating and cooling (air conditioning) of the room.
Many countries have adopted standards that summarize two types of energy savings. Requirement indicators in regions with cold climates and in hot countries are different. An energy efficiency class scale has been created.
In Russia the following classification is used:
- E - low class;
- D - reduced;
- C - normal;
- B - high;
- A is the highest.
There are many different climatic regions in Russia and in each of them the requirements for double-glazed windows differ. For example, from the Moscow region, where heat and cold are average, they include the highest energy efficiency class for both the hot season and the winter.
Price
Within Russia, the same product costs differently.
Not only the manufacturer, prices of materials, but also the region play a role here. It all depends on how far it is from the manufacturer or company. What does it depend on:
- Type of room.
- Block size.
- Product quality.
- Components of the block.
- Window configurations.
- Number of components.
If we consider prices in the capital, then the price of the simplest single-chamber double-glazed window, with a glass thickness of 4 mm, varies from 1,300 rubles. for one sq. m. Thicker glass in a bag (5 mm) – 1450 rubles, 6 – 1600 rubles. Glass coated with an impact-resistant base will add another 600 rubles to the total price. per sq. m. Tempered triplex glass will cost the buyer 3,500 rubles.
About the relevance of this issue
It would be superfluous to say that the specifics of the domestic market (and the building materials market in particular) are characterized by the fact that the client is constantly waiting for some kind of “trick” from sellers and, of course, from manufacturers of plastic windows. Most of us even question the presence of an inner layer of glass in double-glazed windows, let alone energy saving and emissive coating!
Important information! Such emissive glass is usually located on the part of the glass unit that “looks” into the room, and the spraying itself in this case is directed inside the structure.
That is why a double-glazed window will make the house cozier and warmer only if the arrangement of the glass in it meets the requirements. Otherwise, the profitability of an energy-saving window will be clearly in doubt. For more details, see https://liniavikon.com.ua/193-energosberegayuschie-okna.html.
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.
Adviсe
Energy-saving glass is visually difficult to distinguish from ordinary glass. Before purchasing, it is important to make sure that the double-glazed window offered by the supplier is truly energy-saving.
You can distinguish the latter from the usual one using the flame of a candle, lighter, or match. Of course, the easiest way to check in a store or warehouse is with a lighter. To do this, just strike a flame and bring it to the glass unit. If one of the reflected flames (and there will be several of them, since the product consists of several layers) has a different shade (pronounced red), this indicates the presence of a reflective layer. So the test shows that the double-glazed window is energy-saving.
The presence on the glass unit of a special valve for releasing and pumping in argon is also indirect evidence that the buyer is offered an energy-saving product.
You can accurately determine the type of glass unit if you check it with a special device. It is applied from the inside (where there is no button or indicator) to the product. Then just press the button on the device. If the glass unit is energy-saving, the unit will make a characteristic sound and the indicator will light green.
Energy-saving double-glazed windows have their own markings. First of all, such glass is indicated by the letters “K” or “I”. Additionally, the design can be equipped with a heat-saving film, in which case it is marked with the letter “P”. The designation "Ar" indicates the presence of argon between the glasses.
The standard marking of a heat-saving package may look like this - 4M - 16Ar - 4K. This means that the double-glazed window is single-chamber, has 2 lenses 4 mm thick, the distance between which is 16 mm. The inner glass is energy-saving “hard” (K-glass) 4 mm thick. The space between the glasses is filled with argon.
When installing energy-saving structures, it is important to remember that the risk of heat leakage remains with poor-quality sealing and thermal insulation of the window opening. An applied layer of plaster will not cope with this.
Experts recommend finishing the slopes from the inside with sandwich panels based on plastic and polystyrene insulation. External slopes can be insulated with the same thermal insulation material that was used when finishing the facade (usually mineral wool, polystyrene foam, polyurethane foam).
The dimensions of energy-saving glass should not exceed 3x3.2 m. This is due to the fact that when the dimensions of the glass increase, the narrow distance frames remain narrow. In such a design, there is a high risk of depressurization of the glass unit, which means it will lose its energy-saving functions.
The optimal distance between double-glazed windows is 10-15 mm. As the latter increases, the cost of the product increases, but its thermal efficiency does not change in any way.
For residential premises in central Russia, a single-chamber double-glazed window with energy-saving coating is usually sufficient. It replaces the standard two-chamber design.
You can find even more information about energy-saving double-glazed windows in the video below.
Film coating
Plastic energy-saving windows also often include models whose glass receives a reflective coating by gluing a special reflective film to their surface.
The advantages of such models are:
- low cost,
- quite high efficiency,
- ease of execution (including at home).
However, film-coated glass cannot be objectively classified as energy-saving, despite the visible effect.
- Their heat transfer resistance coefficient is lower than that of sprayed double-glazed windows.
- The film is applied to ordinary windows, which means that one of the advantages - the ability to reduce the weight of the structure - loses its meaning.
In addition, the film on the outer surface of the glass is vulnerable to external influences and even with high quality material and careful handling, it is unlikely to last more than 7-10 years.
You can find out more about energy-saving window film on our website in a separate material.
You may be interested to know what mirror tint film is and its types and benefits.
We also have a separate article about which cucumber varieties are best suited for growing on a windowsill in winter.
Kinds
Energy-saving glass can be produced using one of two methods.
In this regard, the following varieties are distinguished:
- K-glass (“hard”) – production is carried out using pyrolysis technology, that is, metal oxide is applied to a hot glass surface. As it cools, the glass and metal oxide are firmly sintered, resulting in increased glass strength.
- I-glass (“soft”) in this case, a three-layer silver dielectric is applied to the glass surface under vacuum conditions. Another layer of titanium oxide is sprayed on top of it, which performs a protective function. The resulting product is inferior to K-glass in terms of strength and resistance to mechanical stress, but has higher heat-saving characteristics.
There is also a multifunctional double-glazed window with a multi-layer coating. The middle functional layer (silver oxide coating) provides the heat-reflecting function of the structure.
The protective outer layer absorbs and reflects the sun's rays, preventing them from penetrating into the room. This protects the room from overheating in summer and dazzling light. In addition, this layer is characterized by weather resistance and serves to protect the glass unit and other layers from the negative effects of the environment.
Finally, the design contains layers on which the light transmittance of the glass, its shade and appearance depend.
Thanks to its design features, the multifunctional window is characterized by energy saving and the ability to keep the room pleasantly cool in the summer heat. When used as one of the layers of mirror glass, privacy can be ensured - the room is protected from prying eyes from the street.
The use of films of different light transmittance allows you to avoid the appearance of sun “bunnies” in the room and glare on the screen of a working TV. The use of colored film as one of the layers provides the decorative function of the double-glazed window.
