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Insulation and R-value
Beginner
Thicker low-k layers reduce heat loss.
R-value (thickness/conductivity) measures resistance to heat flow; layers add. Trapped air is the key to most insulators.
R-20 wall loses heat twice as slowly as R-10.
Gaps and thermal bridges reduce performance.
In more detail
R-value is a measure of thermal resistance used for building insulation, with larger values giving better insulation. It is the thickness divided by thermal conductivity.
Real-world uses
- Building regulations specify minimum R-values for walls and roofs.
- Homeowners compare insulation products by their R-value.
- Homeowners add loft insulation to reduce heat loss through the roof, which lowers heating bills.
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Frequently asked questions
Is R-value the same in all countries?
Units vary, with imperial and metric R-values being different numerically.
How do I improve insulation?
Increase thickness or use materials with lower conductivity.
Does thicker insulation always help?
It helps, but with diminishing returns, because each extra layer reduces the heat flow less than the one before.
Related topics in Heat & Thermodynamics
Greenhouse effect · Thermal equilibrium in the Sun-Earth system · Thermal conductivity of materials · Heat transfer in everyday life