Windows in general are one of the largest sources of thermal transference in a home or office building. As advanced as the technologies we have are, the best R-values for windows have come from triple pane krypton gas filled windows around R-9.8. This is much better that double pane windows which have a maximum R-value of R-5. All of this has changed now that the GlassX quadruple paned windows have become available.
Temperatures are transferred very simply. Cold is attracted to heat and heat is attracted to cold. During the winter, the hot air from your house will drop towards the floor as it cools. This is why return vents are located on the bottom of the wall in cold weather climate homes. In warm weather climate homes, the return is on top of the walls so the cool air that comes out the registers can be returned to the air handler as it get warmer and rises.
Window energy transference happens when the glass surface gets warm or cold. The more panes of glass that a window has that are separated by spacer, the less transference occurs. This is the concept behind insulated windows; Making multiple panes of glass create insulated spaces and increasing energy efficiency.
Quadruple Pane Windows
Quadruple pane windows have four panes of glass, creating three cavities, each with it’s own job in creating the ultimate in energy efficiency.
The first cavity (starting from the exterior) in filled with argon or krypton gas for insulation, and has a prismatic filter that is suspended in the center of the cavity. This filter reflects high angle sunlight and allows low angle sunlight to transmit through the prisms. This is effective in keeping the house cool in the summer and warmer in the winter.
The middle cavity is also filled with argon or krypton gas, but also has a low-e coating for further filtering of the sun’s rays. Low-e coatings perform a similar operation as the prismatic filter.
The last cavity contains polycarbonate channels encapsulating a salt hydrate phase-change material (PCM) that stores heat and releases it slowly back into the room. This technology can add a significant savings to heating costs in the winter time, but is mostly for comfort purposes, all but eliminating convective loops.
The U-value is the measure of how well a material allows heat to pass through it. Energy Star standards require that energy efficient windows need to have a U-Value of .35. Quadruple pane windows have a U-value of .008, allowing an extremely small amount of energy to transfer through it.
These windows are very expensive, around $60-$90 per square foot. The anticipated payback on these windows is between 5 and 10 years depending on the style, equipment, and overall efficiency of the home.
New technologies and building materials are being developed every day. If you have a lot of windows in your home, this could be a great solution to maximize your home’s efficiency.