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

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.

Inert Gases

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.