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How Do Energy Efficient Windows Work?

August 10, 2015

As the days seem to get hotter, our energy bills seem to get bigger as if they were being fed Miracle-Gro. The world is more aware of the need to conserve energy at every possible chance. Moreover, for those of us in Texas, we know where a lot of the heat in our houses is coming from: our windows. While it is nice to be able to see the world outside, by letting in so much sunlight, we also have to fight the side effects of heat and UV ray damage.

The inspiration for windows that help correct the effects of the sun was a natural evolution, and like many feats of engineering, has only gotten better with time.

Energy efficient windows are not that different from other types of windows. In fact, they look the same as other windows. However, the biggest advantage of energy efficient windows is simple - they cut our energy bills. There are many types of green windows, so here is a look into some of the many features offered:

Glass Coatings

Low-emissivity coatings (also known as low-E) are popular. These coatings can reflect the rays of the sun away from your house, thereby keeping a fair amount of heat from getting inside your windows. Glass treated with low-E absorbs less than 35% of the sun's heat rays, while regular glass absorbs about 84%. This coating also helps to keep heat inside your house when it is cold and outside when it is hot, thus cutting down your electric bills. All these coatings are see through and do not obstruct your view or alter the natural sunlight that comes through them.

Spacers systems

Spacers are structural foams made from polymer. The primary function of spacers in energy efficient windows is to create a gap between the two glass panes in the unit. Commonly made of metals, they can also be made from other materials such as silicone, vinyl, and fiberglass.The benefit of using these spacers is to provide relief to the glass panes. Stresses due to differences in temperature can cause the glass panes to expand and compress to some level. The compression and expansion of these panes lower the rate of heat loss (usually denoted as U) by 0.1. The higher the value of U, the lower the efficiency of these windows becomes. The smallest value of U is recommended as they have more efficiency, thus getting the most out of your Windows. Warm-edged spacers come with an added plus of creating a larger thermal effect. It can do this by increasing the affected area beyond the windows edge. Spacers also use a seal to protect against moisture while providing insulation.

Gas Fills

Makers of energy efficient windows also use inert gasses, such as argon or krypton, to great advantage. The gasses are carefully injected between two gas panes to act as a barrier between your home and other outside elements. These gasses have the ability to improve the thermal performance of energy efficient windows and are also clear, odorless and non-toxic. Krypton is thought to work better and is more expensive. It is also the only gas that is ideal for thinner areas that are less than a half an inch. Argon, on the other hand, works well in a typical half-inch glazing. These two gasses can also combine, which could be both practical and more affordable.


When deciding on which energy-efficient window to choose, consider the type of frame it has. Frames that are non-metal have a more improved thermal performance compared to metallic models. Thermally improved non-metallic frames can also optimize your investment in energy efficient windows.[/vc_column_text][vc_column_text]So now that you see there are many different ways to increase the energy efficiency of your windows, you can pull open those shades again and see what is happening in the world again! Wait, is that a brand new Starbucks they put up right across the street?Call Green Energy of San Antonio today and we can get some lovely new energy efficient windows installed for you even faster than another Starbucks can be put in right down the block!