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
LoE-270 All Climate Glass
LoE-366 Low Solar Gain Glass
LoE-340 Solar Control Glass
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