What are Energy Efficient Windows?

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Windows perform a variety of functions, they provide natural lighting, ventilation and a clear views among other things. Today, window manufacturers are not only looking at these traits, but they are also greatly considering energy efficiency. With energy efficient windows you will significantly reduce your cooling and heating costs, which will translate to lower energy bills, and there are even measures that you can take to improve energy efficiency of your already installed windows.

How to select energy efficient windows?
The energy performance rating that you should consider for your windows will greatly depend on the climate around the area where you have built your home. One thing that you should be concerned with is the U-factor; this is a measure of heat flow through a window. An energy efficient window should have a low U-factor, “low” being specified as below 0.22. The U-factor of a given window will depend on a number of things including:

  • Number of glass panes
  • Thermal break
  • The gas in between the various layers of glass

Another factor that you should consider when shopping for energy efficient windows is visible transmittance, where this is a measure of the amount of light passing through a given window. Having a window with a higher value of visible transmittance will, obviously, result in more natural lighting entering your rooms. On the other hand, the Solar Heat Gain Coefficient (SHGC) will help you understand the amount of solar energy that you will be getting through the windows.

What are low-e coatings?
These are thin coatings that are virtually invisible and are usually made from metal or their oxides. By having layers of low-e coatings put on glass, the windows will have better control over heat transfer. Unlike tainted glass, these layers will minimize the rate at which solar radiation will be transmitted while still allowing efficient passage of natural light. This will result to lower heating, cooling and even lighting costs.

Considering orientation of your home
This is where the design of your home comes in when selecting energy efficient windows. It is wise to choose low visible-transmittance for windows facing west to block the strong sun rays that are common in the afternoon. By doing so you will greatly enhance comfort in the affected rooms. The opposite should be done for windows facing north to allow more natural lighting.

A higher SHGC is advisable for south facing windows for maximum heat gain in the winter season. A lower value will suit windows facing east and west. You can also control heat gain or loss for windows facing north by opting for those with low-e coatings.

In short, there is much to gain by going with energy efficient windows including: saving on your energy costs, improving comfort, maintaining a quiet environment, reducing condensation and even protecting your furnishing as well as window treatments. You can also improve on your existing windows through caulking, weather-stripping and installing storm windows.

Article provided by Meridian Windows and Doors mfg.