When it comes to energy-efficient windows, Low-E glass is a marvel of modern materials science. “Low-E” stands for low emissivity, referring to the glass’s capacity to lower the quantity of infrared and ultraviolet light that goes through while maintaining visible light transmission.

How Low-E Glass Stabilizes Indoor Temperatures

Low-E glass technology is based on a microscopically thin, transparent coating—often made of metal oxides—applied to the glass surface. This coating acts like a selective filter. It reflects heat-carrying infrared radiation while allowing most of the visible light through. In the winter, it helps to retain warmth by reflecting indoor heat back into the space. In the summer, it reflects heat from the outside, decreasing the need for air conditioning.

Types of Low-E Glass

There are two major types: hard-coat Low-E and soft-coat Low-E. Hard-coat Low-E is sprayed during the glass manufacturing process and fuses directly to the surface, making it long-lasting and suitable for single-pane storm windows or climates where passive solar heat is helpful. Soft-coat Low-E, applied in a vacuum chamber after the glass is created, provides higher thermal performance but requires sealing between panes to prevent oxidation, which is a typical feature of double glazing.

Low-E Glass and Emissivity

Scientifically, the crucial parameter is the emissivity rating: the lower it is, the better the glass resists radiative heat transmission. For instance, normal transparent glass may have an emissivity of around 0.84, while Low-E glass can be as low as 0.04, significantly enhancing insulation.

Put simply, low-E glass lowers energy bills, stabilizes indoor temperatures, helps prevent furnishings from fading due to UV exposure, and reduces environmental impact.