Energy and glass
Window labels carry a handful of numbers that decide how a window handles heat, sun and drafts. These articles explain what each rating means, which ones matter in which climate and what the glass options do, using the definitions the rating bodies publish.
- Energy-Efficient Windows Explained: NFRC Labels and ENERGY STAR Zones
What makes a window energy efficient, how to read the NFRC label, and which U-factor and SHGC numbers ENERGY STAR sets for each climate zone.
- Windows for Cold Climates: The Numbers That Matter
How to judge a window for a cold climate by its ratings, from U-factor and the ENERGY STAR Northern zone limits to SHGC, air leakage, condensation resistance and frames.
- Windows for Hot Climates: SHGC, Low-E and Frames
How to judge a window for a hot climate: the ENERGY STAR southern-zone SHGC limits, spectrally selective low-E, frames in the heat and window orientation.
- Double-Pane Windows: How They Work and When to Replace
What a double-pane window is, how the spacer, seal and gas fill work, how it compares with single- and triple-pane, and when to replace the glass or the window.
- Laminated vs. Tempered Glass for Windows
How laminated and tempered window glass differ in the way they break, where the code calls for safety glass, and what each does for impact, noise and price.
- Where Tempered Glass Is Required: Doors, Tubs, Low Windows
The safety glazing locations in Section R308.4 of the residential code, as a building department reproduces them, from glass beside doors to low windows and tubs.
- Window Tint and Film: Heat, Glare and Warranties
What residential window film does to solar heat, glare and fading, how NFRC and AERC rate it, and why film on insulated glass can fall outside a window's warranty.
- Argon vs Krypton: What the Gas in Your Windows Does
What argon and krypton gas between window panes do, why krypton shows up in thin triple-pane glass, and how much fill a sealed unit loses over the years.
- Solar Heat Gain Coefficient (SHGC) for Windows
What a window's solar heat gain coefficient measures, why southern homes want a low SHGC, how it trades against daylight, and how to read it on a quote.
- Soundproof Windows: What Actually Cuts Outside Noise
How laminated glass, mixed pane thickness, air space and seals affect window noise, what STC and OITC ratings mean, and what manufacturers publish.
- Low-E Glass Explained: What the Coating Does and Which Kind You Need
How a low-E coating reflects heat, hard coat vs soft coat, why the right SHGC depends on your climate, and how gas fills work alongside the coating.
- Storm Windows: Interior vs Exterior, Low-E Storms and What They Cost
How interior and exterior storm windows work, what low-E storms add, when a storm makes more sense than replacement, the downsides, and what surveys say they cost.
- Triple-Pane Windows: What the Third Pane Changes and What It Costs
What a third pane of glass does to U-factor, weight and noise, where ENERGY STAR's limits make it most useful, and how survey prices compare with double-pane.
- Window U-Factor Explained: What Is a Good Number for Your Climate?
What a window's U-factor measures, NFRC's five label ratings and their ranges, what counts as a good U-factor in each ENERGY STAR zone, and how to compare labels.
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FindAWindowPro is a lead-generation service, not a contractor, installer or manufacturer. The articles are general information, not legal or financial advice. We are not affiliated with the manufacturers named.