The combination of glass panes, Low-E coatings, gas ﬁlls and spacers are considered an “Insulated Glass Unit” (IG unit). Collectively, they enhance the energy performance of your windows. The Seal Smart™ system packages use the following IG units of performance to create a customized, energy-efﬁcient window.
Panes of Glass
Single pane windows provide, at best, modest insulation for your home. The use of double and triple panes of glass provide the structure for various options of higher levels of energy efﬁciency and home comfort.
Insulated Glass Units secure two or three panes of glass together into an airtight unit, utilizing spacers to hold the panes apart and seal them together at the same time. Choosing the right spacer option can equally impact the energy efﬁciency of your windows. The performance of the spacer in the IG unit is critical because it helps determine the energy efﬁciency of your window as well as its longevity.
Low-E coating on the surfaces of the glass block certain IR and UV rays. It is a microscopically thin, virtually invisible, metallic layer deposited on the glass surface primarily to reduce the U-factor (lower U-factor means better insulation) by suppressing radiant heat ﬂow. Low-E coating is virtually transparent to the solar spectrum and reﬂective of long-wave infrared radiation.
When you order Vista windows with Low-E you get a double coating of Low-E as a Vista standard. Other companies charge you more money for this option. Low-E3 coating is available for extreme performance.
Various inert gases, which are better insulators than air, are used to ﬁll the inside of the glass unit. The space between the glass is often the most important aspect of window performance.
Argon and Krypton are odorless, colorless, non-toxic inert gases that can be used instead of air between panes of glass to increase insulation and energy efﬁciency. Argon is an excellent insulator; a good value and more readily available. Krypton is a more dense gas and therefore a better insulator in triple pane glass units.