Application Environment

Low -e Windows

Switchable Glazing

Typical Uses and Projects

Commonly used to create a more comfortable environment with the ability to use less energy by reducing the UV factor and thus heat flow¹.

When certain types are induced with an electrical current, they are used to provide privacy screens. They can be tinted, opaque, or colored.  One unique use is windows on Boeing 787 which replace window shades.  Other uses include saving energy and controlling the amount of light and heat admitted into spaces⁶. Also, they're found in rear view mirrors, sunroofs¹¹, ambulances, and boats¹².

Building Types

Low-e windows have the ability to be used on any type of window glazing where a metal or gas can be used in between two pieces of glazing⁷.  Therefore it can be used in residential and commercial applications, but it is more common in residential buildings⁸.

This can be used for high-rise and low-rise offices, retail, food service, institutions, arenas, and residential buildings⁵.

Affordability

Can be 10-15% more than a regular-comparable window¹⁶.  Based on an average home of 10-18 windows, the use of low-e windows can provide enough electrical savings to cover the cost of the windows in 9-18 months.  Over the span of 8-10 years, the savings from the low-e windows will provide enough money to replace the windows⁴.

Can be two to three times the cost of regular window, but the long term benefits out weigh the short².  Additionally, the electricity required to turn on/off the transparency is only .32W/per sq.ft³.

Regional Use

First used in cold climates, then designed for warm climates that emit up to 40% less solar heat.  Regions can have different recommended levels or types: high, moderate, and low solar gain.  For example, the North/Central region of the U.S. is specified as "Moderate Solar Gain Low E Windows¹."

It is versatile and can be used in both cold and warm climates⁵.

Unfavorable Conditions

In techniques of applying low-e films, the seams between applied pieces can spread open if not installed properly¹⁴.  Also, it can be difficult to quickly test and verify different types of low-e films¹⁵.

 Unattractive issues include shorter warranties of 5 years on switching functions, where levels of light change rapidly it can take too long to switch from colored to bleached tints.  In addition, there are some problems with adaptability¹³.