What Is I-89 Glass?
I-89 glass is an advanced Low-E glass technology designed to significantly improve energy efficiency and indoor comfort. It reflects heat back into your home while maintaining clear, natural views.
Think of I-89 as a thermal mirror built into the glass — invisible, but highly effective.
What Makes I-89 Glass Different?
Most energy-efficient windows use Low-E coatings. I-89 goes further by placing a high-performance coating on the interior surface of the insulated glass unit.
This placement allows I-89 to reflect radiant furnace heat back into the room instead of letting it escape — especially valuable in colder climates.
How I-89 Glass Works
A transparent microscopic metallic coating reflects long-wave infrared heat while allowing visible light to pass through — improving insulation without darkening the glass.
Winter Performance
Interior heat reaches the glass and is reflected back into the room, reducing heat loss.
Comfort & Clarity
Warmer interior glass surfaces with clear views and minimal haze.
Near Triple-Pane Efficiency in a Double-Pane Window
One of the biggest advantages of I-89 glass is how much insulation it adds without requiring a full triple-pane window.
When used in a double-pane insulated glass unit, I-89 can achieve U-factor performance approaching some triple-pane configurations, meaning significantly less heat loss using only two panes of glass.
For many homeowners, this means stronger comfort and efficiency without the added weight or cost that triple-pane windows can introduce.
Key Benefits of I-89 Glass
Lower heat transfer and better insulation.
Warmer glass and fewer cold spots.
Clear views with high light transmission.
Scratch-resistant and easy to clean.
Available in annealed or tempered options.
Pairs well with argon gas fills.
Why KV Custom Windows Uses I-89
KV Custom Windows integrates I-89 glass as part of a balanced window system that can include argon gas fills, performance spacers, and quality frames — delivering excellent efficiency without unnecessary bulk.
Windows are a system: glass, gas fill, spacer, frame, and installation all work together. Great glass helps — and professional installation is what makes the performance real in the home.
I-89 Glass FAQ
Does I-89 glass look tinted?
No — it’s designed for clear views and high visible light transmission.
Is I-89 better than triple-pane?
Triple-pane can be the top option in some situations, but I-89 can deliver near-triple performance while staying lighter.
What else matters besides glass?
The full system matters — frame quality, gas fills, spacers, and installation.
Can I-89 be used in different window types?
Yes — it works across many window styles, including tempered safety applications.
Want I-89 Glass in Your Next Window Upgrade?
If you’re planning a window replacement and want to compare glass packages, explore high-performance windows available for local homes.
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