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Window Tech Specs

The most efficient glass in the world comes standard.

The best windows in the world come with glass made by Cardinal®, including all windows produced by household names like Pella® and Andersen®. It’s the best insulated, longest lasting glass pack available, and we’re among the only Michigan window manufacturers who can offer it.

Triple insulation
Figure 1 Together, the three insulating elements—the low-emissivity layer(s), the insulating spacer, and the argon gas fill combine to create an exceptionally efficient glass unit.

Low-emissivity (low-E) coatings prevent heat from passing through glass, and can reduce energy loss by up to 85% (Kennan & Rissman 2014). Our standard low-E glass easily exceeds the latest Energy Star 6.0 requirements, but that’s only half the story, since the Northern climate standards don’t make sense for Michigan. They reward windows that let in heat from the sun, to warm the home during winter. But we get almost no sun during winter—and we get lots in July.

We’ve designed our glass offerings to suit Michigan homeowners. We didn’t go with glass that sounds great just because it’s Energy Star certified. We’ve gone a step further to make sure that our windows don’t create hotspots during summer, and drive up A/C costs.


Every window comes with a premium-quality LoE2-270 coating, applied to the exterior pane. This makes the window highly efficient and comfortable in Michigan by itself, and we offer an interior LoE-i89 coating option as well, to deliver performance normally achieved only by boutique products.

Transmittance SHGC1 U-factor R-value Fade UV Fade ISO
69% 0.36 0.20 5 0.14 0.51
Table A The LoE2-270 glass pack exceeds Energy Star 6.0 requirements for Michigan’s climate, and more importantly, makes your home comfortable during hot Michigan summers, with low solar heat gain.

LoE3-366 plus LoE-i89 is the gold standard.

Cardinal® IG Low-E options

For truly cutting edge performance, we offer Cardinal’s best insulated glass. Picture this: in January, when it’s a frigid 20°F outside, a LoE3-366 glass surface will remain at 60°F inside. And LoE3-366 will also protect your flooring and furniture against color fade.

Transmittance SHGC U-factor R-value Fade UV Fade ISO
63% 0.27 0.20 5 0.05 0.41
Table B The LoE3-366 plus LoE-i89 glass pack exceeds Energy Star 6.0 requirements for Michigan’s climate, makes your home comfortable during hot Michigan summers, and provides exceptional performance in the winter.

Glass units are filled with insulating argon.

Instead of filling the sealed space between the panes of glass with air, we use moisture-free argon40, which is substantially more resistant to thermal transfer than air (Sabatiuk 1983). Argon boosts energy efficiency and is also completely safe—it’s an inert, non-flammable, and non-toxic gas.

[1] “SHGC” stands for solar heat gain coefficient; you can learn more about what this measurement means from Understanding the NFRC Label.

Kennan, Hallie & Jeffrey Rissman. (2014). "Low-Emissivity Windows". Case Studies on the Government’s Role in Energy Technology Innovation. 2014(June).
Sabatiuk, P.A. (1983). "Review of gas-filled window technology: summary report". The ASHRAE/DOE Conference–Thermal Performance of the Exterior Envelopes of Buildings. 1982(2).