glass types
Loē-i81

Weve got your number

Introducing Loē-i81?, the new Cardinal glass that takes center of glass U-factors to a remarkable 0.20 when coupled with Loē2? or Loē3? glass and argon fill in a double-pane unit. Without argon and with or without capillary tubes, the unit still delivers a U-factor of just 0.23 – perfect for high altitudes. You get triple pane performance in a double-pane window. So take your window U-factors to a new low… with Loē-i81.
There’s no need to go to triple-pane windows to meet the various energy-saving guidelines. No need to invest in redesigning your windows and altering your manufacturing processes either. A double-pane IG unit with Loē-i81 can meet the guidelines.

Turn your double-pane windows into triple-pane performers

Loē-i81 is sputtered onto the indoor lite, the #4 surface, thus reflecting escaping heat back into the room and lowering U-factors. Coupled with our Loē2 or Loē3 glass and argon fill, this double-pane unit delivers performance much better than clear triple-pane – a center of glass U-factor of just 0.20 compared to 0.35 with clear triple-pane.
To surpass the U-factor performance of Loē-i81 IG double-pane unit, you would need to go to a triple-pane unit with a low-E coating in each gap.

IG unit (U-factor)
Double-Pane, Clear, Air (0.48)
Double-Pane w/Loē3-366, Argon (0.24)
Double-Pane w/Loē3-366 and Loē-i81, Air (0.23)
Double-Pane w/Loē3-366 and Loē-i81, Argon (0.20)


1″unit (U-factor)
Triple-Pane, Clear (0.35)
Triple-Pane w/Loē3-366, Loē-180, Argon (0.17)
Triple-Pane w/Loē3-366, Loē-180, Loē-i81, Argon (0.15)

Meet today strictly energy efficiency guildlines

With a center of glass U-factor of only 0.20 (0.23 without argon) and SHGC of just 0.25, an insulating glass unit with Loē3-366 and Loē-i81 meets the most stringent energy standards – without going to a triple-pane unit.
This allows us to offer more double-pane window options that can meet current ENERGY STAR guidelines everywhere in the country, including high altitudes, regardless of window size.

More double-pane windows meet advanced requirements

Loē-i81 helps more configurations meet stringent U-factor requirements in the Northern zone without triple pane glazing. Use the interactive chart below to see how including Loē-i81 in your window designs makes the difference.

The advantages are more than clear

In addition to providing maximum energy efficiency in a double-pane unit, Loē-i81 offers several other customer-pleasing benefits.
Cardinal IG units with Loē-i81 also incorporate their XL Edge? spacer, one of the reasons we have the industry’s lowest failure rate – only 0.20% over 20 years.

Glass Performance