Double-Paned Glass Windows
It's difficult to over-stress the importance of using energy efficient double-pane windows in your home. According to the United States Department of Energy, up to 25 per cent of heat loss in homes is due to thermal exchange through windows. In these cases, windows are often comprised of thin glass panes that are easy to break. These panes also allow for a significant amount of thermal exchange from the interior of a home to the exterior.
This is true with both heating and air conditioning. You can stand near one of these older windows and feel the draft coming off of it. However, the draft you feel is not necessarily wind from the outside. It's simply a thermal current that is nothing more than the result of a pressure gradient between warm and cold air. This is perhaps one of the most dramatic displays of how poorly-designed windows can significantly contribute to energy inefficiency.
If you want to start saving money through energy efficiency, you should really focus on your windows. Without energy efficient windows, almost all of your other energy efficient changes could be rendered useless. After all, there's no point to getting a more efficient furnace if you'll just end up losing all the heat through your windows.
Why are Double-Pane Windows More Efficient?
There are a couple of answers for this question. Most people simply assume that two panes are better than one. The reality of why these windows are more efficient is quite complex. In truth, the two major features that make these windows efficient are a gas barrier and the material of the window.
Gas Between the Window Panes
Double-pane windows actually have 5 total barriers that help mitigate potential thermal exchange. These 5 barriers are the two panes, an insulating interior/exterior finish, and a gas barrier between the panes. This gas barrier is actually one of the most important features of double-pane glass windows.
Krypton or argon gas is injected into the space between the window panes during fabrication. Both krypton and argon are much denser than the Earth's atmosphere. This means that heat and cold have a significantly more difficult time getting through. Both krypton and argon are inert gasses that pose no threat to the health of humans and pets. In fact, trace amounts of these gasses are in the air you breathe every day. By placing these gasses between the window panes, the thermal resistance of the window is greatly increased.
Glass Material Used
The glass used in double-pane windows is different to regular glass panes. The glass used in these windows is specially tempered to be thicker and more resistant to thermal exchange than traditional windows. The glass is also coated with a high R-value microfilm that further enhances the resistance of the glass. When all of this is put together, you have a much more efficient glass material that is better at keeping interior temperatures stable.
Double-Pane Glass Window Considerations
First and foremost, it is important to recognize how much money the average person can save on their home heating and cooling bill when efficient windows are used. In a best-case scenario, the average homeowner can save up to 25 per cent of their yearly heating and cooling costs by upgrading their windows. This is a very real, very noticeable, and very immediate benefit of upgrading to double-pane windows. The average person will see new windows pay for themselves after only a couple of years.
People interested in upgrading their windows should consider the importance of replacing all windows at once. If you only upgrade one window at a time, then you will not see the energy saving benefits. Piecemeal upgrades like this still leave parts of your home susceptible to energy loss. The only way to reap the benefits of these windows is to replace all of your windows at the same time. This can be very expensive, so many contractors are willing to work with their clients on payment plans.
Finding a Certified Window Contractor
Installing double-pane windows to replace old single-pane windows will require you to hire a contractor. Industry standards on window sizes and mounting hardware have changed since single-pane windows were common. This means that you will likely have to cut into your inner and outer walls to install the windows. This is best done by a certified window installation contractor. These contractors are trained in the safest, most efficient installation techniques. Hiring a contractor to install your windows will help you save a significant amount of time and money. This is especially true if you don't have much home improvement experience.