Double glass gas – Under construction

What is between the moons of Glazing of a PVC windows? Is it air, a special gas or a vacuum? Does the efficiency of the leaves vary somewhat when the gaseous substance that fills them is changed? Knowing the answers is important. This will help you choose the windows for your home.

What is the difference between a drink and several glasses?

One of the main functions of glazing is thermal insulation of the interior of our house. In technical jargon we talk about the coefficient of Thermal transmittance (U symbol, but in the case of glass add the letter « g » from English glass), ie the amount of heat given off by the moon. If we compare Ug on a single (monolithic) glass with the thermal transmittance of a double glass, we will see that the difference is significant. Ug of monolithic glass gives an average of 5.7 to 5.8 W / m2K. Ug per double glazing can be around 2.7 W / m2K (almost half), but there are also manufacturers such as Drutex whose double glazing can reach Ug of 0.8 W / m2K. As we can see, it is convenient to install PVC windows at least two windows (if the glasses are three or four, the benefits will be even better).

What gases is the double glazing chamber filled with?

Between 30 and 50% of the heat transfer achieved through double glazing is achieved through thermal conductivity or convective movements of the gases that fill the glass chamber. Although the insulating glass inner tube can be filled with this air, the best manufacturers use heavy or rare gases, mainly argon, krypton, and xenon, for this purpose. Since gases are denser than the atmosphere, they offer more thermal efficiency Air, which reduces the U-value of the glazing. It is the use of argon gas that allows IGLO 5 CLASSIC windows to achieve Ug of 1.00 W / m2K, about 10% less than double glazing with air between the panes. In addition, noble gases increase the sound insulation (approx. 3 dB).

Argon – price / performance ratio

The denser the gas in the glazing chamber, the better the thermal and acoustic density. Of the three gases mentioned above, xenon is the heaviest and therefore the one that insulates the best. However, it is also the most expensive. If we look at the value for money, it turns out that filling the cameras is the most useful Argon gas.

Argon is a colorless, odorless and inert gas (it does not cause chemical reactions). It occurs naturally in the earth’s atmosphere. It is therefore a safe gaseous substance.

Because it is denser than air, it insulates better against temperature changes and noise. To improve the second factor, it is sometimes mixed with sulfur hexafluoride (SF6), a better bran remover. The usual ratio is 75% SF6 and 25% argon. The heat permeability is slightly higher, but the decibels that reach the interior of the house are reduced.

Argon – conditions that guarantee high thermal efficiency

However, the main property of argon gas is its high thermal efficiency. Compared to Ug of ordinary double glazing with a heat transfer coefficient of PVC windows with argon, 0.1-0.3 W / m2K is better. Thanks to this, we not only reduce the size of heating bills. We also reduce the thermal bridges in the inner glass and prevent condensation. In short, being at home is healthier, more comfortable and cheaper.

However, there are two details that we need to consider. First of all, so that the Ug value corresponds to the value specified by the manufacturer, your hose PVC windows must be filled with at least 85% argon. For example, the window glazing that Veneo distributes contains 90% argon and 10% air.

On the other hand, the sheet metal should not lose more than 1% of the noble gas volume per year to ensure that its insulating properties are effective for at least 10 years.

If you are planning on buying new windows for your home, pay special attention to the gasoline filling your cameras. Also request tests that confirm the inert gas content and leak rate. You can also check for condensation « with the naked eye ». But it’s best to prevent it from happening that way.