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Energy Efficient Windows

Energy Efficient Windows – What Does it Take to be Called an Energy Efficient Window?

Purchasing energy efficient windows is one of the smartest things you can do for a home. Whether you are building a new home, or replacing your old windows, high performance windows are a must. With energy costs rising, newer, better performing windows will help save on your heating and cooling bills.

A new set of energy efficient windows will also help to make your home more comfortable by keeping out the cold in the winter and the heat in the summer. A more comfortable environment will create an inviting and enjoyable living environment.

Efficient windows also help the environment because they insulate your home better which means it requires less energy to heat and cool your home and therefore less fossil fuels, coal, and natural gas are consumed to produce the energy.

If you are researching to find out about the best windows for your project, it is helpful to know what to look for in a high quality window before purchasing any for your project. The information on these pages will allow you to truly understand what is meant by an energy efficient windows.


Fifty plus years ago most windows were manufactured with single pane glazing (glass) and installed into a wood, steel, or aluminum window frame. Houses that are seventy, eighty, or more years old, most likely, had only single pane wood windows in the home.

Back then energy costs were low and most people did not even have air conditioning so they were able to live with a single pane non-energy efficient window in the house. If it was hot they opened a window, if it was cold they put another log on the fire or turned up the heat. Energy efficiency was not a topic of concern during that time.

However, as energy costs began to rise and building requirements started to become more stringent, a new design became available in the window market, double pane glass. Double pane insulated glass is created by joining two pieces of glass with a spacer and sealing the edges around it to create a vacuum tight airspace in between the glass.

Double paned glass provides a better efficiency rating than the single pane because of its insulated airspace. The dead air space between the two pieces of glass creates an additional “layer” between the outside and inside of the window. Houses twenty to thirty years old are more likely to have double pane windows than single pane, however, single pane windows still existed in the market twenty to thirty years ago.

While the dual pane glass creates better performing windows than its predecessor, the single glazed window, the addition of low-e to the windows has improved overall window energy efficiency substantially. Low-e is a mostly transparent coating that is applied in between the glass on an insulated glass. This coating reduces solar heat gain and prevents heat from transferring across the insulated window. This means the home stays cooler in the summer and warmer in the winter.

The last evolution in energy efficient windows was the introduction of a gas filled air space. This is typically done using argon or krypton. Both are inert gases that are injected into the airspace between the panes of glass in an insulated window. The gas molecules are heavier than oxygen and create a “heavier” airspace in between the glass. This denser air reduces the amount of convection currents in between the glass which in turn reduces the heat gain moving across the air space. The gas filled airspace coupled with a low e coating will create very energy efficient windows.

Most of the history lesson above focused on the glazing portion of windows. While the glass makes up a majority of the window, each element of the window, including the frame plays a part in determining how energy efficient a window is.

Making your home more energy efficient involves much more than just installing better windows in your house. If you are looking for more tips to make your home more energy efficient, you should visit Green Energy Efficient Homes.

With energy costs rising, replacement windows are not the only thing a homeowner should consider when trying to lower their energy costs. To lower your energy costs you should look at every home energy savings option to find other ways to reduce energy costs in every aspect of your home.

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