The heat-insulating and noise-proofing properties of metal-plastic windows directly depend on the quality of the double-glazed window inserted into the frame. Many buyers mistakenly think that the operational data of the PVC window is determined solely by the parameters of the frame profile, so they pay little attention to the double-glazed window. And it occupies more than 80% of the total window area and affects not only the light transmittance of the structure, but also the level of heat conservation and sound insulation in the house.
A variety of glass units are presented on the market, differing in thickness and type of glass, number of glasses, thickness. To choose the right window, you need to know what types of double-glazed windows are for plastic windows, which parameters are mandatory to pay attention to, and which are secondary, which qualities are really useful, and which are nothing more than advertising "tricks".
Content:
Varieties of double-glazed windows by the number of cameras
Structurally, a double-glazed window consists of two or three parallel sheets of glass installed at a certain distance from each other. Sheets are glued to a special design - a spacer made of metal or plastic of a given width.
It performs several functions:
- connects glass in one design;
- determines their parallelism;
- seals the internal cavity (chamber);
- strengthens a double-glazed window;
- allows you to remove excess moisture from the camera.
According to GOST 24866-2014, two types of double-glazed windows are produced in Russia - single-chamber (SPO) and two-chamber (SPD). Single-chamber consist of two sheets of glass and one distance frame, two-chamber - of three sheets of glass and two frames. The same GOST also provides for other structures consisting of four or five sheets of glass. But such double-glazed windows are most often made by special order and make up a small percentage of the total production of windows.
Glass for double-glazed windows is used only by the highest brand M1, the so-called float glass. It is produced using a very interesting technology, invented in the UK in the 50s of the last century. It consists in the fact that molten glass (a mixture of sand, dolomite, soda ash and lime, Tmelting≥ 1000 0C) is poured into a bath of a given shape on a layer of molten tin (Tswimming= 232 0FROM). Tin melt has all the properties of a liquid, the main of which in this case is the formation of a perfectly flat horizontal surface. The high density of the metal eliminates the appearance of waves and mesentery from air movements.
Glass mass is poured onto a metal mirror, which spreads over the surface with a layer of a given thickness and cools down to the temperature of complete crystallization. The sheet of the obtained glass has an exceptional accuracy of parameters, high transparency and the absence of defects that occur, most often, during uneven cooling.
Part of the float glass is used immediately after cooling, part is tempered - reheated to a high temperature, below the melting point and abrupt cooling. As a result, the internal structure of the material changes, it becomes stronger and safer. When destroyed, it does not crumble into fragments, but into rectangular pieces that are unable to cut or injure a person in any other way. Some double-glazed windows are built on the basis of precisely tempered glass.
Single chamber double-glazed windows
The most common of the double-glazed windows.It is used in almost all technical windows for offices, industrial premises, retail outlets, restaurants, cafes, warehouses. A significant part of PVC windows in houses and apartments are also equipped with single-chamber double-glazed windows.
The main advantages:
- light weight;
- sufficient level of thermal insulation;
- high light transmission;
- low price.
The thickness of the glass unit is in the range of 24 - 54 mm with a glass thickness (standard) of 4 mm. Some of the double-glazed windows can be made of glass of greater thickness, but the total width of the packet does not exceed the permissible range.
It is very convenient to use single-chamber double-glazed windows using energy-saving glasses. One of the main advantages is retained - the ease of construction, and the heat-shielding properties increase significantly.
Double-glazed windows
This design is also included in the main types of double-glazed windows for plastic windows. Recently, the vast majority of windows for the residential sector is made with this type of glazing. The total width of the package does not exceed the dimensions of a single chamber - 18 - 54 mm. Three sheets of glass with a thickness of 4 mm occupy 12 mm of the width of the glass packet, the rest falls on the air chambers. Naturally, the widest double-glazed windows have the highest level of thermal insulation.
The sound insulation level of two-chamber double-glazed windows is much higher than that of single-chamber windows, but it can be further increased using distance frames of various widths - sound waves in this case are actively attenuated as a result of asynchronous vibration of the glasses.
Three-chamber double-glazed windows
They are used slightly less than two-chamber and much less often than single-chamber.
There are several reasons for this:
- a large mass of wings, which requires the use of more durable, and, therefore, expensive fittings;
- slight increase in soundproofing properties;
- reduction in light transmission;
- reducing the thickness of the air chambers;
- increase in value.
Three-chamber windows (4 sheets of glass, 3 distance frames) are justified only when using windows in very cold climates with an increased frame width. In ordinary windows, in addition to accelerated wear of the hinges and a decrease in the intensity of natural light, no more effect is observed. The same restrictions apply to four-chamber windows, which can only be considered as special structures for special operating conditions.
The difference between double-glazed windows depending on the gas used to fill the chamber
The main properties of a double-glazed window - heat permeability and sound insulation, largely depend on the gas that is pumped into the chambers. Light transmission practically does not depend on this - here the main role is played by the characteristic of the glass itself.
Dry air is pumped into ordinary double-glazed windows of a budget level, it has a sufficiently low thermal conductivity, high transparency and does not differ in chemical composition from atmospheric one. More expensive glass units use argon, krypton or xenon - inert gases that are completely harmless to humans. Do not be afraid that in case of damage to the sealing layer, these gases will penetrate into the room. Even if this happens, they do not pose any danger.
The price of such double-glazed windows is somewhat different, it depends not so much on consumer properties as on the cost of gas. Argon is the cheapest, the most expensive is xenon. Inert gases exhibit their main qualities when used in double-glazed windows equipped with energy-saving glasses (i or K). But even with ordinary glasses, some indicators improve, although the changes are not so pronounced.
Useful qualities of inert gases:
- reduction in thermal conductivity;
- reduced risk of condensation;
- protection of internal i-spraying from oxidation.
But with obvious advantages, double-glazed windows filled with inert gases are not without drawbacks.The main one is that the gas must be pumped at a pressure above atmospheric. This requires increased strength of the sealing layer at the end of the glass. The high penetration of an inert gas determines its leakage through the smallest seal defects. Even in the best double-glazed windows, up to 3% of gas disappears in a year.
The average effective life of an energy-saving window filled with an inert gas is 10 years; after this period, the glass packet must be filled with gas again. This is due to some inconvenience and extra costs.
In addition, there is another risk factor - inert gases are odorless and colorless; it is extremely difficult to determine what is pumped into your window. If you buy an expensive window from a trusted manufacturer, you can be sure that it is inert gas in the chamber. But in other cases, such confidence is not 100%.
| Filling | Density, kg / m³ | Thermal conductivity, W / (m * k) | Dynamic viscosity, kg / (m * s) | Heat capacity, J / (kg * k) |
|---|---|---|---|---|
| Air, at a temperature of +100C | 1,232 | 2,496 | 1,761 | 1,008 |
| Argon (Ar), at a temperature of +100C | 1,699 | 1,684 | 2,164 | 0,519 |
| Krypton (Kr), at a temperature of +100C | 6,360 | 1,275 | 1,459 | 0,614 |
What are the double-glazed windows for functional purpose
The main types of double-glazed windows for plastic windows are standard float glass and air as a filler. The practice of using double-glazed windows shows that it is such an option that is the most practical both in terms of operational properties and price. A well-made one or two-chamber double-glazed window fully satisfies all the requests put forward to plastic windows and in a temperate climate of mid-latitudes, nothing better can be desired.
But progress is relentless - PVC window manufacturers are constantly working to improve designs. Sometimes the differences between a conventional double-glazed window and an advanced one are understood only by specialists. Some innovations seem, at first glance, completely redundant, but upon closer examination, the advantages are quite real and significantly improve the functionality of metal-plastic structures (both windows and doors).
Multifunctional double-glazed windows
The first, and one of the most common improvements, concerns glasses, as the main element of a double-glazed window. In multifunctional double-glazed windows, silver or chromium molecules are sprayed onto ordinary glass. Almost invisible under normal lighting, it does not transmit long-wave radiation (infrared spectrum), which avoids overheating of the room in the heat with direct sunlight. In addition, in cold weather, such double-glazed windows contribute to the preservation of heat, since the applied coating reflects the heat coming from heating devices inside the room.
At the same time, the entire visible spectrum passes through the glass without delays or restrictions - the light transmittance of the glass unit does not differ from ordinary glass. Spraying is carried out only on glass that is inside, in the case of a single-chamber package, on the inner plane. It is very stable and designed for many years of use, in practice its durability does not differ from the life of the entire window structure.
This design of a double-glazed window allows you to save up to 30% more heat in a house than a regular double-glazed window, which affects the reduction of coolant consumption. Such double-glazed windows in houses with an autonomous heating system are especially beneficial. Also, a multifunctional double-glazed window has enhanced sound insulation. A light mirror effect reduces the ability to view the premises from the street, and the retention of a significant part of the ultraviolet light protects indoor plants from overheating.
Self-cleaning double-glazed windows
A very practical and convenient invention. The glass on the outside is coated with a special transparent substance that has the lowest possible adhesion to most household and industrial contaminants.Also, the coating has the ability under the action of ultraviolet to decompose any substances adhering to the glass. The resulting products are easily washed off by rain or showered under the influence of wind. Dirty water on such glasses does not leave streaks or stains.
If there is no rain for a long time, the glass can simply be poured with water from a hose from a garden pump or water main. Such glasses are very convenient in the windows of high-rise buildings, glass facades, shop windows, it is practical to install them in the cottage or house in the fixed wings of wide windows. The self-cleaning double-glazed window has the same transparency as a regular one. In one set, you can combine self-cleaning glass with energy-saving or tempered, increasing the versatility of the glass.
Noise-insulating double-glazed windows
Comfort in the house depends on several parameters, among which one of the main ones is silence. For cottages or country houses, this may not be so relevant, but for apartments (shops, restaurants, offices) overlooking busy streets or highways, noise insulation is indispensable.
The design of soundproof double-glazed windows is somewhat different from ordinary ones. Thicker glasses up to 6 mm are used here. The outer glass is usually triplex glass. As a rule, for soundproof windows, three-chamber double-glazed windows filled with argon or krypton are used. These gases have a lower sound conductivity than air due to the higher density, which determines a more tangible resistance to the propagation of sound waves.
Often soundproofed double-glazed windows are made with cameras of various widths - this reduces the risk of resonant vibrations and the amplification of certain sound frequencies, instead of attenuating them. Even a difference of a few millimeters can significantly increase the level of sound insulation.
The quality of installation of components is very important:
- glasses;
- distance frames;
- fittings;
- sealants.
The overall level of reduction of external noise, in such double-glazed windows, is quite realistic to reduce by 25 - 30 dB. Even in the neighborhood of a six-lane freeway, the noise level in the room will not be higher than 55 dB, which corresponds to the level of a quiet conversation or the working noise of the office. The same windows facing the ordinary city street will reduce the noise level to barely audible 30 dB.
Soundproof double-glazed windows cost a little more than usual, but an increase in costs of 25-30% is justified - comfort in the house is more important than money. Moreover, there will be little need for soundproof packages - one or two windows go out onto the busy and noisy streets.
Mirror double-glazed windows
Double-glazed windows with a mirror coating are appropriate not only on the ground floor - often mirrored glasses completely change the exterior of the house and turn a completely ordinary plain building into a masterpiece of architecture.
In addition to high protective properties (from ultraviolet radiation and immodest looks), they also have an increased level of strength. The thinnest metal film has a high resistance to random mechanical influences and is absolutely not afraid of abrasives - silver or golden metal is sprayed onto the internal surfaces and does not interact with the external environment.
But when installing a mirrored double-glazed window, several factors should be considered:
- relevance in building design;
- maintaining relative "opacity" only in the daytime;
- higher cost.
When you turn on the internal lighting in the house, everything that happens in the room becomes clearly visible on the street, as when using ordinary glasses. Save on curtains and blinds will only work in offices or stores.
Colored double-glazed windows
Double-glazed windows with colored glasses are usually used as part of the decoration of the facade. But having indisputable design capabilities, they do not lose and are purely applied.Stained-glass windows perfectly protect the house from excess ultraviolet, do not allow viewing the room from the street, while at the same time letting in enough daylight. Also, using colored glasses, you can create original interior lighting, giving a certain color.
In most cases, color is given to the window by special films glued to the glass by lamination. But one can also find glass tinted throughout the volume, into the composition of which various compounds are introduced during manufacture that change color without losing the basic qualities - strength, heat resistance, chemical inertness.
The first version of double-glazed windows is more common - a relatively low cost allows the manufacture of painted windows in an industrial way in any size. Colored glass, painted in the array is quite rare, such double-glazed windows can be ordered individually from only a few manufacturers.
In addition to an attractive appearance, colored glasses have increased strength. Lamination film prevents glass from cracking during accidental impacts and is not inferior in strength to triplex or tempered. But when ordering color double-glazed windows, you should not get carried away with color saturation - a light shade is quite enough, not reducing transparency too much.
A special case of colored double-glazed windows is tinted (darkened) by gluing special films. Such windows are very appropriate in modern interiors, but, in addition to decorativeness, they also have excellent operational properties. Especially on the south, southeast side of the building or in the hot climate zone. In the latter case, it is not thermal insulation properties that come to the fore, but the window's ability to protect the room from direct sunlight and the high temperature of the outside air.
Double-glazed windows with smart glass
Fashionable in the modern world, the word SMART is applied to self-regulating systems that react in a certain way to changes in external conditions. In relation to windows, these are complex double-glazed windows that change the level of transparency and thermal conductivity depending on external conditions. A complex interlayer is installed between the glasses, powered by an external current source, which responds to changes in lighting intensity and temperature.
The complexity of the system determines the relatively high cost of such windows. Most often they are used in “smart home” systems, which are distinguished by the complexity and high price of the main components and components. If in such a house the cost of a “smart” window is 2–3% of the total cost of equipment, then in an ordinary apartment or cottage they will exceed 20, or even 30 percent, of the construction costs.
Example of changing the transparency of smart glass:
Energy-saving double-glazed windows with k-glass
The essence of these double-glazed windows is that a thin layer of metal oxides, mainly silver, is sprayed onto ordinary float glass. Waves of electromagnetic radiation are reflected from it.
In practice, this is reflected in an increase in the heat-reflecting ability directed to the side with a higher temperature. This contributes to the absence of heat in summer, in a room protected by such windows, and to minimize heat loss in winter. The spraying thickness of 0.4-0.6 microns does not reduce the transparency of the window, but significantly enhances it mechanically. K-glasses are distinguished by the comparative simplicity of the technology and do not add too much to the cost of the entire structure. If there is a choice between k and i-glass, then we definitely need to dwell on the K-version. In addition to lower cost, throughout the entire period of operation, such double-glazed windows will not bring any surprises.
Double-glazed windows with i-glass
The glass manufacturing technology for such bags is much more complicated than the “K”. Spraying is carried out in a vacuum and provides a kind of “sandwich” spraying, alternating oxide and metal layers (oxide-metal-oxide). Moreover, the thickness of the metal layer (most often silver) is not more than 10-15 nm (10-9m).
Even such a thinnest layer of metal reduces the thermal conductivity of the package by 90%, without changing the light transmission. But the spraying is quite vulnerable to external influences, therefore it is made exclusively on the inner surfaces of the glasses. At a comparative cost with K-packages, i-options can save 20% more energy spent on heating. In addition, they are also 20 - 40% lighter, which makes it possible to install single-chamber, i-packages of any size in walls with not very high load-bearing capacity and in large-area structures - showcases, facades, panoramas.
Double-glazed windows of increased strength
The main requirement for double-glazed windows, which are installed in windows on lower floors or in industrial premises, is strength. Of course, it is practically impossible to protect the glass from breaking, but it is not difficult to protect the window from accidental impacts and wind loads. For these purposes in double-glazed windows use: triplex, tempered or reinforced glass. They have a fairly high strength, transparency and reasonable price.
1. Triplex is a multilayer construction of float glass and a polymer film glued with transparent glue. When damaged, the sheet does not crumble into fragments, pieces of glass remain glued to the film and do not pose a danger to others.
2. Tempered glass is heated to a certain temperature (above T melting point) and abruptly cooled in air or industrial oils. As a result, its strength increases significantly and physical properties change - the strength increases by 3-5 times, and the bending resistance is not less than 2 times. Upon destruction, small pieces of a parallelepipedal shape are formed, unable to injure a person.
3. Reinforcement is carried out by gluing a glass mesh onto a glass or mounting it inside the glass during production. Sometimes it is not polymer that is used, but a steel mesh structure. Such glass has a rather original appearance and a slightly reduced transparency, but its strength is not inferior to metal.
Variety of double-glazed window decor
Most double-glazed windows are an ordinary plane without excessive decor. But other options can be used, for example, glass with spros - decorative metal profiles installed inside the glass packet. Profile width is between 8 - 26 mm. The color of the spros is silver, gold, bronze. They have a fairly decorative look, but have recently been practically not used.
In addition to spros, false overlays are used - decorative elements of various configurations that are attached to the glass. They have no effect on the strength and tightness of the double-glazed window, but they allow you to adapt any window to the features of the exterior of the building.
There can be many options for manufacturing double-glazed windows. If there is a choice, then professional builders should be involved - windows are not bought every year, and they cost a lot. The comfort of the home and the healthy atmosphere in the house depend on their quality.
