When choosing double-glazed windows, it’s not just the price (although it’s an important parameter) that you should pay attention to, but also other characteristics. These may be the size, shape, type of profile, and brand. The number of layers also affects your choice. Among the most commonly used windows are double-layered and triple-layered structures, which are also called single- and double-chambered windows, respectively. Let’s analyze their composition, differences, advantages, and area of application.

The composition of two- and three-layer insulated glazing units

All windows consist of two main components – profile and glass. The first takes about 30% of the glass unit, while the second – up to 70%. Of the additional components, we should highlight the fittings. Both the profile and the glass can be different, and their construction and composition primarily depend on energy-saving characteristics. It is the number of chambers in the profile, which varies from 3 to 6, and the number of chambers between the panes (the most popular are 1 or 2 chambers, rarely 3-chambered structures) that influence the ability to retain heat in the house.

A single-chamber glazing window consists of two glass panes that have a space between them, called a chamber. A two-chamber construction consists of three glass panes – two external and one internal. The number of chambers affects the insulation characteristics first: the more of them, the better the window retains heat in the house. They often inject inert gas, which conducts almost no heat, into the chambers. The gas used is almost always argon as it is safe for people and plants and does not evaporate, due to which the glass can be used without a “refill” for up to 10 years and more.

Another characteristic of modern windows is that they use coated glass containing tin and silver ions, which work like a mirror and reflect more than 60% of the escaping heat back into the room.

It’s obvious that the energy efficiency of 3-layer structures is higher than that of 2-layer ones, yet the latter have their own advantages, described below.

The thickness of two- and three-layered double-glazed units

A single-chamber construction usually consists of two glass panes 4 mm thick and a distance between them (the chamber itself) of 16 mm. Thus, the total thickness of double-glazed units is 2.4 cm. Thus, the total thickness of double-glazed units is 2.4 cm (0,9 in).

Obviously, the three-layer glazing unit is thicker. Dimensions of each layer:

  •   Three glass panes of 4 mm.
  •   The first chamber – 16 mm.
  •   The second chamber – 14 mm.

So it appears that the standard thickness of a three-layer double-glazed window is 4.2 cm (1.6 in), although there are other sizes.  As we mentioned earlier, they also produce 4-layer windows with a thickness of up to 6 cm (2.4 in). Yet their use is justified only in conditions of severe cold, where winter temperatures fall below -40⁰C (-40⁰F); in warmer regions, though, a 3-layer structure will suffice for effective energy conservation.

The weight of the insulated window depends on the number of chambers, so it is clear that single-chamber structures weigh less than double-chamber ones, and noticeably so.

Advantages and disadvantages of 2-layer and 3-layer insulated glazing units

The basic advantage of double-glazed windows is in weight and price, which are both significantly lower if compared with 3-layered structures.

A single-chamber window weighs about 20 kg per 1 sq. m., while a two-chamber product will weigh 30 kg/m2. The difference is considerable. Less weight simplifies the transportation and installation process. Such a window reduces the load on the walls and will be more securely fixed in the opening. One more advantage is that more light enters the room through a single-chamber glazing unit. If you compare prices, you will find that they are lower for two-layer windows; however, the difference is not so critical – about 25-30%.

Yet, all the benefits of single-chamber structures pale into insignificance if you want to save money on heat. Two-chamber windows are far ahead here. When analyzing the energy efficiency of the entire system, you should also consider the number of chambers in the profile, the number of coated glass panes in the overall system, and their thickness. Either way, if you install three-layer structures, you will have to spend much less money on the heat in the winter.

The glass coating also plays a major role. For instance, the energy savings of a single-chamber glazing unit with a coating will be higher than that of a two-chamber glazing unit with normal panes. When it comes to soundproofing, the latter wins.

Field of application of 2-layer and 3-layer insulating glass units

One-chamber double-glazed windows with ordinary glass panes (rather than energy-saving) may be quite suitable for installation in regions with mild winters, where temperatures rarely fall below -10⁰C (14°F).

They are commonly used when glazing balconies, except when these areas are set up as an additional room with heating. With the installation of a one-chamber insulated glass unit, the loggia or balcony will serve as an additional chamber between the street and the main room.

Choosing a one-chamber design is a perfect solution when glazing summer cottages and summer kitchens, especially if you don’t spend much time out of town in the winter. Such double-glazed units are placed on patios that are used more often in the warmer seasons.

Two-chamber or 3-layer windows are mounted in the main rooms in regions where winter temperatures fall below -10⁰C (14°F). Installing them is worthwhile if your house is close to traffic interchanges or other noisemakers. Having paid extra money once, you will later feel more comfortable, save money on heating and keep the precious heat away from the street.

Therefore, the difference between the two-layer and three-layer structures in terms of heat and sound insulation is very substantial. But if you don’t want to overpay, carefully weigh all factors and only then order installation.