A Window Into Efficiency

Every year, I spend countless hours putting those plastic sheets over my windows for insulation. The bigger the window, the bigger the pane in the glass, the more time I spend and the more energy I lose to the winter. We often neglect insulation when it comes to energy expenditures because it only lowers heating bills. Conventional wisdom says one sheet of glass per window, but conventional wisdom is being overturned in favor of energy efficiency.

Putting in energy saving windows has limits. Sure, a three foot thick pane of glass would increase a window's efficiency and keep heat in really well, but isn’t that too heavy?  You could probably combine materials and make something lighter and more efficient, but what would that new-fangled material cost?  What we need is to strike a balance between aesthetics, practicality and efficiency?  Well, that's exactly what Team Tennessee's Living Light solar house does.

Living Light - Engineering from Living Light on Vimeo.

Living Light efficiently increases the insulation of the house without increasing thickness of the glass. By adding another piece of glass and filling the space between the glass with strips of mylar film—a common polymer used to insulate spacesuits—the “R-value” of the glass increases with little change in size and no change in visibility. What’s the R-value? It’s a constant that correlates to a material's resistance (the R) to temperature change. Thicker materials have a higher R-value, but some materials—mylar as compared to glass—resist changing temperature more effectively and allow for thinner, lighter windows. Living Light's windows reduce drafts and overall heat movement, as well as deaden sounds from outside the home. 

Certainly, other homes tackle efficiency differently. Team California spent more time and effort on insulating the entire house. Notice how few windows they have, the front door being the only real window. The design gives the house a distinctly futuristic look, and definitely stands out. The University of Maryland's team didn't use the ranch-style blueprint of other solar decathletes, strategically placing many of the windows to avoid drafts and cooler parts of the home. Team New Jersey spaced out lots of small windows, distributing light and insulation throughout.

But what's clear is a truly solar home cannot rely solely on the power of the sun. Little things like mylar in between windows account for big-time energy savings, helping our homes attain net zero energy use. And really, anything to keep me from putting up those plastic sheets on my windows.


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