Insulating glass units (IGU) - a transparent construction, which consists of two or three glass sheets, which are hermetically conjoined to each other along contour through distantial frame and forms one or two separate chambers, which are filled with dried air or inert gas.

Insulating Glass components

Glass

Glass is used to provide light and allow vision through otherwise opaque surfaces. IGU's most important feature is it's dimensional stability over a wide temperature range.

Tinted Glass

While clear glass is the most common glass component of IGUs, tinted glass may be used to reduce solar heat gain or as an architectural feature. The principle colors available include bronze, gray and green. The degree of tint depends on both the composition of the glass and the thickness of the lite. Tinted glass is usually placed on the exterior of the IGU.

Low-Emissivity Glass

Low-emissivity (Low-E) glass has a thin coating, often of metal, on the glass within its airspace that reflects thermal radiation or inhibits its emission reducing heat transfer through the glass. A basic low-e coating allows solar radiation to pass through into a room. Thus, the coating helps to reduce heat loss but allows the room to be warmed by direct sunshine. The low-e coating is usually on surface #3; if solar control is required then the coated surface is moved to surface #2 to reflect or absorb solar radiation. The change in location of the coating does not affect the insulating properties of the IGU, only the percentage of solar heat gain. Further solar radiation control can be added through the use of tinted glass and/or metallic coatings. Low-e glass reflects the radiation rather than absorbing it improving performance compared to the glass in a simple greenhouse. Its effect can be noticed by an increase in temperature of the inside glass surface and the reduction of condensation that would normally form on the unit because of a change in the dew point.

Spacer

The glass panes are separated by a "spacer". Most spacers are constructed of either thin gauge steel or aluminium for thermal expansion stability or cost reasons. In cold climates, this may result in water or ice forming at the bottom of the sealed unit because of the heat loss in those areas. To reduce heat transfer through the spacer and increase overall thermal performance, the spacer may be constructed of fiberglass or use a hybrid design of metal and plastic (»warm edge» type). Typically, the spacer is filled with desiccant to remove moisture trapped in the air space during manufacturing, preventing condensation from forming on surface #2 when the temperature falls below the dew point.

Hermetic

Hermetic inside of glass packet is necessary in order to create a hermetic chamber between glasses to form a proof barrier to prevent  water steam molecules from getting into the chamber, as well as gas escape from the chamber. It is achieved during two hermetization phases. The first hermetization- it is a polyisobutylene, also called butylene, which is applied in a regular layer with a special automat butylextruder on already mounted outer angle of the distantial frame prior to adjustment of the glass packet. Its main function- protection against water steam admission into inside of the glass packet and gas escape from it. Repeated hermetization is performed using binary polysulphate, main function of which is a development of a resistant, elastic connection between glasses and frame at a molecular level. It also serves as extra protection against water steam admission and prevents gas escape.