Energy efficient windows are not a recent technological breakthrough. These windows have a history that stretches back several decades. It has taken less than a century to jump from uber-thin window panes that let in heavy drafts to glazed and coated windows that are nearly impenetrable. Let’s take a look at the evolution of energy efficient windows.
How It all Began
The origins of energy efficient windows stem back to the 1920s when architects launched efforts to improve the comfort of those who lived/worked in buildings. This push led to the creation of insulated glass units (IGUs) and windows with double-glazing. Iron-rich glass with green tint was also implemented to minimize the level of heat transferred from the sun to building interiors.
Uncle Sam Steps In
The federal government soon became heavily involved in the push to decrease energy use. After conducting extensive research, it was clear that windows were one of the primary sources of heat loss. Studies showed that about one-quarter of home heating costs were attributable to heat loss through windows. Research and investments made by the federal government are partially responsible for the breakthroughs outlined below.
Before the 1970s the majority of windows were single pane with a wooden frame perimeter. Those who lived in cold parts of the nation attempted to minimize heat loss with the use of storm windows. Multi-pane windows were implemented toward the latter portion of the 70s in an attempt to boost energy efficiency. Similar to storm windows, multi-pane windows created an insulating layer with additional glass. This style of window evolved to the point that this space was filled with inert gasses like argon to boost insulation.
The Move Away From Aluminum
As the 80s rolled around, window manufacturers began to learn that aluminum frames were insufficient for insulation purposes. Manufacturers transitioned to wood-vinyl and vinyl composite frames to boost efficiency and lower heat transfer. Manufacturers also switched out metal spacers that kept multi-pane windows separate with new plastic/foam spacers. Such non-metallic spacers served as superior insulators.
The Low-E Era
By the late 80s, window manufacturers began to use low-emissivity (low-e) glass containing a metal oxide layer that permitted visible light to pass through and also prevent heat from seeping outward. This glass was actually made with several thin layers of gold that created a green tinge. By 1981, low-e glass coatings were completely colorless thanks to the use of silver in place of gold. Low-e glass did more than merely keep the warm indoor air inside the home/office. It also functioned as an excellent means of preventing heat from entering the home during hot summer days.
Energy Efficient Windows of Today and Tomorrow
Modern day efficiency windows are absolutely spectacular in every regard. They are visually attractive, easy to use, offer an excellent return on investment and most importantly, they keep warm/cool air inside the home. As time progresses, we are figuring out more ways to reduce home utility bills and keep homeowners as comfortable as possible.
Researchers are currently working on special window coatings that use electric current that is sensitive to outdoor conditions. Absorbing Electrochromic (AE) windows utilize a thin material to alter shade levels with electric currents. This style of window is built with a light sensor that automatically alters the level of electrical current. These futuristic windows turn darker when subjected to sunlight and transition to a translucent state when there is minimal outdoor light. Contact us for more information.