Window Glass, Part One: Look Into Your Windows
Seaway Manufacturing of Erie, PA,
In the earliest homes, windows were very small – or nonexistent. Glass was extremely expensive, and a home with windows almost certainly meant that the occupants were wealthy. Over the course of a few centuries, manufacturing processes improved and costs came down dramatically, so now it’s hard to imagine a home without large vistas in nearly every direction.
But today’s larger window openings bring their own set of problems. By itself, the glass that makes up most of a window’s area is not much of an insulator; that is, the single pane of glass found in most older windows is not very good at keeping outside temperatures outside and your expensive heating and cooling inside.
Modern replacement windows answer this need by using an insulated glass package, two or more panes of glass with a sealed airspace in between. This design provides energy efficiency that’s far superior to single-pane windows, but can also bring confusion with a dizzying array of options: clear or low-E glass, double- or triple-glazing, Argon or Krypton gas, spacers, U-values … what are the best choices?
We’ll address each of those items in this series, but the answer depends on your individual situation, starting with which region of the country you live in. Recognizing that a home in Arizona is likely to have very different insulating needs than, say, a home in Vermont, the EPA has divided the United States into several Energy Star Climate Zones. These can be a good first point of reference in determining what to look for in a window.
Next, consider your home specifically. Does one side receive much more sunlight than the others? If so, you may want to consider a higher-efficiency glass package for the windows on that side of the house. Similarly, certain combinations are better at reducing outside noise, so if your home faces a busy street you might want an upgraded glass package in the front windows only.
With those general considerations as a starting point, we’ll move through the elements of a window glass package one by one beginning in the next post.