Glass Packages


The below table demonstrates EnerLux’s different glass packages and their center-of-glass energy performance. Each glass package is called EL Glass XXX. The model number is derived from the first number of the glass package’s R-Factor, SHGC and VT. For example EL Glass 725 has an R-Factor between 7.0 and 7.9, a SHGC between 0.20 and 0.29 and a VT between 50% and 59%.

7 – R-Factor is 7.2

2 – SHGC is 0.21

5 – VT is 57%

Glass Package U-Factor R-Factor SHGC VT Panes Components
EL Glass 378 0.26 3.8 0.70 80% Double LoE-180 & Clear
EL Glass 437 0.25 4.0 0.37 70% Double LoE-270 & Clear
EL Glass 426 0.24 4.2 0.27 66% Double LoE-366 & Clear
EL Glass 413 0.24 4.2 0.18 39% Double LoE-340 & Clear
EL Glass 757 0.13 7.7 0.56 70% Triple LoE-180, Clear, & LoE-180
EEL Glass 736 0.13 7.7 0.33 62% Triple LoE-270, Clear, & LoE-180
EEL Glass 725 0.13 7.7 0.24 57% Triple LoE-366, Clear, & LoE-180
EL Glass 713 0.13 7.7 0.15 34% Triple LoE-340, Clear, & LoE-180

Performance data calculated with Lawerence Berkley National Laboratory’s Window 5.2 NFRC 100-2001.
The standard EL Glass gas fill is 95% argon.


U-Factor – A measure of the rate of non-solar heat loss or gain through a material or assembly. It is expressed in units of Btu/hr-sq ft-F (W/sq m-C). The lower the U-factor, the greater a window’s resistance to heat flow and the better its insulating value.

R-Factor – A measure of the resistance of a glazing material or fenestration assembly to heat flow. It is the inverse of the U-factor (R=1/U) and is expressed in units of hr-sq ft-F/Btu. A high –R-value window has a grater resistance of heat flow and a higher insulating value than one with a low R-value.

Solar Heat Gain Coefficient (SHGC) – A measure of how well a product blocks heat caused by sunlight. The SHGC is the fraction of incident solar radiation admitted through a window (both directly transmitted and absorbed) and subsequently released inward. SHGC is expressed as a number between 0 and 1. The lower a window’s solar heat gain coefficient, the less solar heat it transmits in the house.

Visual Transmittance (VT) – A measure that shows how much light comes through a product. The visible transmittance is an optical property that indicates the amount of visible light transmitted. VT is expressed as a number between 0 and 1. The higher the VT, the more light is transmitted.

LoE-180 High Solar Gain Glass
Glass Package Options - LoE 180

Cardinal LoE -180 delivers excellent cold weather performance – its insulation value (U-factor) is a low 0.26, and with a high solar heat gain coefficient (SHGC) of 0.69, it lets the winter sun’s heat pass into the home. It also blocks 71 percent of the sun’s harmful UV rays. While blocking out the cold and UV rays, it lets the daylight stream in – more light than ordinary low-e glass.

LoE-270 All Climate Glass
Glass Package Options - LoE 2 270

Cardinal’s LoE-270® glass is the perfect solar tuned glass for all season comfort. It reduces solar heat gain by 50% or more when compared to ordinary glass. Although it is a clear glass, LoE-270 even outperforms ordinary tinted glass typically used in sunny climates. And though it’s coated, LoE-270 lets the light shine in to warm your house during the cooler winter months.

LoE-366 Low Solar Gain Glass
Glass Package Options - LoE 3 366

The full-year benefits of LoE -366 can be clearly seen. When the temperature soars in the summer, ordinary window glass just can’t beat the heat. Tinted glass spoils the view. LoE -366 is formulated to reject solar heat while maintaining attractive visibility. So it keeps the heat out while letting light in. As a matter of fact, LoE -366 glass is our ultimate in performance and clarity among all of Cardinal’s clear coated products. What’s more, LoE -366 provides the ultimate in fading protection. It blocks 95% of the sun’s damaging ultraviolet rays – a leading cause of fading (visible light also contributes to fading) – so your furniture, carpets, curtains and wall coverings stay beautiful for years.

LoE-340 Solar Control Glass
Glass Package Options - LoE 3 340

When it comes to reducing solar heat gain from the blazing western sun, LoE-340 simply has no equal. And because it’s not tinted, you enjoy a number of other advantages as well. First, there’s the cost savings of no tint. Then you avoid the disadvantages of tinting: the potential for thermal stress breakage and the potential need to heat treat the glass. Tinted glass has several other glaring deficiencies. Regular tinted glass works by absorbing sunlight, so the glass becomes hot in the sun. The color of the glass also changes with its thickness. On the other hand, LoE-340’s appearance and performance remain the same regardless of glass thickness. What’s more, LoE-340 has a very high LSG (light to solar gain ratio) of 2.17. So even though solar gain is being controlled, plenty of visible light is still allowed inside.

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