The finer points of windows

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Q. I had replacement windows installed because the old ones were 60 years old and falling apart. Afterward I stood at the street to admire them. and noticed the color of some windows was different. Some were purplish, while all the others had a green tint. My question is, Why could I not get clear glass, and why were some of the windows greenish and some purplish? Why weren’t they at least all the same?

A. Great question! Depending on the choice, the glass for those frames came from a different manufacturer than the window unit frame maker. Windows are fabricated using parts made by specialty companies, in most cases. Further, there are vinyl window frame companies that just make vinyl frames, without inserting separating materials made of foams, metals, polyamide plastics or neoprene (like the rubber material that lines the window edges on LIRR cars).

The purpose of the added materials is to stabilize the inserted glass panes and create what is known as a thermal break, which is just what it sounds like: a barrier to allowing cold or heat to conduct right through the frame from outdoors to indoors. Having no break in many windows makes them a poor choice in the long run, since you lose more costly energy after saving money on the original installation.

The glass is made of sheets that are turned back on themselves or are separate sheets, often coated with a fine silver misting that is 175,000 times thinner than a dollar bill. The edges of the glass are then sealed, and in many cases a gas, usually argon, is pumped in between the two panes of glass. This slows the conductivity of the glass and the change in temperature through the window pane.

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