Guide
How to Read an NFRC Window Label
Read U-factor, SHGC, visible transmittance, air leakage, and condensation resistance as separate metrics.
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Guide category
Energy And Performance Guides
Browse homeowner window replacement guidance about energy and performance.
Available guides
Guide
U-Factor vs Solar Heat Gain Coefficient
U-factor addresses heat transfer; SHGC addresses admitted solar heat.
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What Low-E Glass Does
Low-E is a thin coating within a glazing package; the exact coating and complete rated window determine performance.
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Double-Pane vs Triple-Pane Windows
Pane count changes the glazing assembly, but it does not replace exact ratings, product details, or installation scope.
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What ENERGY STAR Certification Means for Windows
Certification confirms that an eligible product meets program criteria; it does not predict one home's utility bill.
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Choosing Windows for Hot Climates
Compare complete-window ratings and each opening's exposure rather than choosing from a coating name or pane count alone.
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Choosing Windows for Cold Climates
Use climate-zone criteria and exact whole-product ratings, then evaluate each opening and its installation.
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Choosing Windows for Mixed-Humid Climates
Mixed-humid projects need a balanced whole-product comparison across cooling, heating, rainfall, and indoor-moisture conditions.
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Window Condensation: What Location Tells You
Where moisture appears changes the questions to ask; condensation alone is not a remote diagnosis.
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Sound-Reducing Windows: What Affects Results
Noise results depend on the complete assembly and surrounding opening, not pane count or frame material alone.
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