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R-value measures thermal resistance of insulation. Higher R-values reduce heat transfer; proper insulation is critical for energy efficiency.
Formel
Heat flow = ΔT / R_total (sum all resistances including air films)
Trin-for-trin guide
- 1R-value = thickness / thermal conductivity
- 2Heat flow = ΔT / R_total (sum all resistances including air films)
- 3Recommended: R-30 attic, R-19 walls, R-10 basement walls (varies by climate)
Løste eksempler
Input
Attic insulation R-19 (insufficient for cold climate)
Resultat
Upgrade to R-50 could reduce heating 25-30%
Major savings potential
Almindelige fejl at undgå
- ✕Only insulating attic (walls and basement important too)
- ✕Neglecting air sealing (more important than insulation alone)
Ofte stillede spørgsmål
Does more insulation always save money?
Initially yes, but with diminishing returns. R-60 attic (vs. R-50) saves <5% extra for higher cost.
What's the best insulation material?
Fiberglass, cellulose, foam have similar R-values per thickness. Choose by cost, environmental impact, and application.
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