Modern technologies can greatly improve the properties of the glass by covering the surface with a metallic oxide layer that is invisible to the naked eye, thus significantly improving the thermal properties (heat reflection) of the glass. This type of glass is called low-emissive glass (Low-E), and it reflects 40%-70% more heat compared to regular glass. Since thermal insulation is one of the key requirements for today’s windows, the use of Low-E glass in manufacturing IGU has become the norm. Standard insulated glass units (IGU) are produced by using two glass panes, one of which is made of Low-E glass.

A higher level of thermal insulation can be achieved by using a triple-insulated glass unit where two of the glass panes are Low-E. The use of triple IGU increases heat permeability, which can be up to twice that of double-glass windows. However, one disadvantage is the increase of the IGU weight and thickness, and a decrease in light conductivity.