Glazing with reinforced thermal insulation

In homes and commercial buildings, glazed walls are no longer simply designed to let in natural light; in addition to their transparency, they offer a number of other properties such as thermal or acoustic insulation, solar control, anti-reflective properties...

There is a growing desire to limit energy consumption, on the one hand for reasons of economy, and on the other to reduce atmospheric emissions (carbon dioxide CO ₂ , nitrogen oxides NO _x , sulfur dioxide SO ₂ ...), with the motivations of reducing the greenhouse effect and protecting the ozone layer. In this context, the German government, which wanted to reduce CO ₂ emissions by 25% between 1987 and 2005, enacted an ordinance aimed at limiting the energy needed to heat buildings. These provisions have amplified the development of insulating glass units that are more efficient than conventional double glazing: reinforced thermal insulation double glazing featuring, on one side, a thin layer that is transparent in the visible range but highly reflective in the thermal infrared range, i.e. low emissivity.

The use of these low-emissivity thin films is explained by the physical – electrical – properties of the materials deposited in this form. The glassmakers opted for materials with metallic properties that reflect thermal radiation. Two ranges of materials were chosen: silver-based metallic thin films deposited in very fine thicknesses, of the order of ten nanometers, and thicker transparent oxide-based conductive thin films, of the order of a few hundred nanometers. In both cases, deposition methods and layer characteristics are described.

Finally, we'll look at other examples of applications for glass substrates coated with conductive thin films, in addition to enhanced thermal insulation glazing.