Heat Transfer Calculator
Our heat transfer calculator helps engineers and builders calculate thermal performance. Compute heat flow through walls, determine insulation requirements, and optimize energy efficiency for buildings and equipment.
Results
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thermostat R-Values (per inch)
home Recommended R-Values
- 🏠 Attic: R-38 to R-60
- 🧱 Walls: R-13 to R-21
- 🪟 Windows: R-3 to R-5
How to Use This Calculator
Select Mode
Choose to calculate heat loss, R-value, or required thickness
Enter Material Data
Input thickness, conductivity, and area
Set Temperature
Enter the temperature difference
View Results
See heat transfer rate, R-value, and U-value
The Formula
Heat flows from hot to cold. Conduction transfers heat through solids. R-value measures insulation effectiveness (higher = better). U-value is the inverse (lower = better).
Q = (k × A × ΔT) / d or Q = U × A × ΔT
lightbulb Variables Explained
- Q Heat transfer rate (W or BTU/hr)
- k Thermal conductivity (W/m·K)
- A Surface area (m² or ft²)
- ΔT Temperature difference (°C or °F)
- d Material thickness (m or in)
- U Overall heat transfer coefficient (W/m²·K)
- R Thermal resistance (m²·K/W)
tips_and_updates Pro Tips
Higher R-value means better insulation
R-values are additive for multiple layers
U-value = 1/R-value
Include air film resistance for accurate calculations
Thermal bridges significantly reduce overall R-value
Moisture reduces insulation effectiveness
Frequently Asked Questions
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Data sourced from trusted institutions
All formulas verified against official standards.