Low-E Vs. Double-Pane Windows

Low-E

• Low-E glass reflects heat away to reduce its capacity to pass through windows. "Low-emittance," or "low-E," windows have a microscopically thin and virtually invisible glazing coat made of metal or metallic oxide materials. Low-E glass reduces the ultraviolet, or U-factor, of glass and thereby suppresses the radiative flow of heat through glass.

Double-Pane

• Double-pane glass windows have two thicknesses of glass, stuck together with a variable amount of air space in between the two pieces of glass. The resulting benefit is glass that improves insulation from heat and/or sound. The pocket of air between the two sheets of glass is dried so that the space is airtight to eliminate the possibility of condensation and to maximize the insulation properties of double-pane glass.

Similarities

• Low-E glass and double pane glass are used for various residential, commercial, industrial and institutional applications. Windows are the most common application, followed by use for full-glass doors or inserts within doors that contain other materials such as wood. In residential applications, both types are most commonly used for windows and doors that face the outdoors. In commercial and institutional applications, they are used for windows as well as for interior purposes. For example, low-E and double-pane glasses are used in office buildings to define personal office spaces for employees. Each type provides desirable soundproofing benefits, and as a result, provides an option to segmenting spaces for individual offices or room settings instead of installing a wall.

Differences

• Low-E glass is a single pane of glass with coatings to reduce UV penetration from outdoors to indoors. Double-pane glass has two sheets of glass, separated by a spacer. The coating used for low-E glass is invisible, while the space between double-pane glass is detectable by the naked eye. Double-pane glass may display visible signs of condensation build-up in between the two sheets of glass over time. However, this will not happen with low-E glass.