Thermal Conductivity Calculator Formula
Understand the math behind the thermal conductivity calculator. Each variable explained with a worked example.
Formulas Used
Heat Flow Rate
heat_rate = conductivity * area * delta_t / thicknessVariables
| Variable | Description | Default |
|---|---|---|
conductivity | Thermal Conductivity (k)(W/(m·K)) | 0.04 |
area | Area(m²) | 10 |
delta_t | Temperature Difference(°C) | 20 |
thickness | Material Thickness(m) | 0.1 |
How It Works
Thermal Conductivity (Fourier's Law)
Fourier's law describes the rate of heat conduction through a material.
Formula
Q/t = k * A * DeltaT / d
where k is thermal conductivity, A is area, DeltaT is temperature difference, and d is thickness. Lower k means better insulation.
Worked Example
Heat loss through a 10 m² wall, 10 cm fiberglass insulation (k=0.04), 20°C temperature difference.
- 01Q/t = k * A * DeltaT / d
- 02Q/t = 0.04 * 10 * 20 / 0.1
- 03Q/t = 8 / 0.1
- 04Q/t = 80 W
Frequently Asked Questions
What materials have the highest thermal conductivity?
Silver (429), copper (401), and aluminum (237) in W/(m·K). Metals are generally excellent conductors.
What makes a good insulator?
Materials with very low thermal conductivity: fiberglass (~0.04), styrofoam (~0.03), aerogel (~0.015), and still air (~0.025 W/(m·K)).
How does wall thickness affect heat loss?
Heat loss is inversely proportional to thickness. Doubling the insulation thickness halves the heat loss rate.
Ready to run the numbers?
Open Thermal Conductivity Calculator