In the vernacular, we often talk about double glazing. However, there are quite a few types of "double" glass. A better term is actually "insulating glass. By insulation glass we mean all types of insulating glass that insulate better than single or standard (non-HR) double glazing.
Double glazing is also called thermopane, as the brand name of a German manufacturer that introduced it to the Dutch market in 1948. It is the first double glazing. Double glazing consists of two sheets of glass held apart by a so-called spacer at the edge of the glass. The space between the sheets of glass is called the "cavity. The edges of the glass are sealed with a special sealant to create a closed unit. In standard double glazing, the space between the glass is filled with air. It is hardly used in facades these days. In a few cases it is still used indoors for sound insulation.
With HR glass, the glass is coated on one inner side (i.e., in the cavity), making it more insulating. The metal layer allows solar radiation to pass through and reflects long-wave radiation. The more effective the metal layer, the better the insulation. Therefore, less energy is then needed to heat the room inside. HR Glass has improved considerably over the years. The following HR generations can be distinguished:
The more "pluses" behind HR, the better the glass insulates. The article The difference between HR, HR+, HR++ and HR+++ glass explains exactly what the difference between the different types of HR glass is.
Triple glass consists of 3 panes of glass coated with insulating gas, making it super insulating. It is also known by the terms HR+++ glass, triple glass or triple glazing.
