At first glance, choosing the right window glass for your replacement windows can be overwhelming; you might be thinking, “can’t I just get some good ol’ normal glass anymore?” Well, the long and short of it is, if you’re thinking old, single-pane glass, then, you might still be able to get it. However, you ought to know that your old-fashioned single-pane glass is, without a doubt, your worst choice for energy-efficiency.
Multiple glass panes
Today’s energy-efficient windows require at least two panes of glass for any sort of actual energy efficiency; in colder climates, up to three panes can be used in windows. This is because the air between the multiple panes of glass, in conjunction with the glass itself, acts as a buffer that reduces the amount of heat that is transferred from the outside to within your house as sunlight passes through the window glass. The entire thing is sealed against air leakage, which also has the added benefit of reducing outside noise filtering into your home.
Inert gas fills
To further reduce the amount of heat transfer from outside to inside, the space between the window panes can be filled with an inert gas, such as argon or krypton. Argon is the more common of the two, and provides superior insulation when compared with normal air. Krypton, similarly, provides even more insulation than argon when used to fill the spaces between your window panes.
The glass itself that is used in windows can have many different characteristics built into it. Low-emissivity, or low-e, glass, for example, comes with a microscopically-thin coating of a metal oxide that further increases the insulating properties of the glass, reducing heat transfer between your home and the outside environment. Other options include heat-absorbing tinting, which is designed to reduce both heat transfer and glare, and reflective coatings, which are geared more towards reducing the penetration of radiant light than blocking heat transfer.
How, exactly, does this work out in actual numbers? SmartSun glass, the newest offering from Renewal By Andersen, for instance, is 45% more efficient in the winter and 70% more during the summer, when compared to regular dual-pane glass. This means that, by choosing SmartSun glass, you can reduce your heating bills by 45% more than the current industry standard in the winter, and 70% more than the same industry standard during the summer.
Your window’s frame and glass, no matter how advanced, won’t count for much if they’re not part of a properly-installed window. More in Part III.