Fourier conduction
q = -k x dT/dx
k = thermal conductivity
Air property calculator
Thermal Conductivity of Air Calculator
Calculate thermal conductivity of dry air from temperature for heat-transfer and HVAC engineering checks.
Instant air conductivity solver
Enter air temperature
Results update automatically using interpolated dry-air thermal conductivity values at 1 atm. Use Celsius, Fahrenheit, or Kelvin.
Calculated result
Formulas
Thermal conductivity formulas and conversions
Common conversions
1 W/(m.K) = 0.577789 Btu/(hr.ft.deg F)
1 W/(m.K) = 0.01 W/(cm.K)
K = degrees C + 273.15
The calculator linearly interpolates tabulated dry-air thermal conductivity values at standard atmospheric pressure. Use detailed gas-property data for high-temperature, humid, or pressurized systems.
Reference table
Thermal conductivity of air reference table
| Temperature (°C) | Thermal conductivity, k (W/m.K) |
|---|---|
| -20 | 0.0219 |
| -10 | 0.0230 |
| 0 | 0.0241 |
| 10 | 0.0251 |
| 15 | 0.0256 |
| 20 | 0.0260 |
| 25 | 0.0263 |
| 30 | 0.0267 |
| 40 | 0.0275 |
| 50 | 0.0283 |
| 60 | 0.0290 |
| 70 | 0.0297 |
| 80 | 0.0304 |
| 90 | 0.0311 |
| 100 | 0.0317 |
Guide
How to use this calculator
- Enter the air temperature.
- Select the temperature unit: °C, °F, or K.
- Use the interpolated dry-air result for early HVAC, airflow, heat-transfer, or fluid mechanics checks.
Reference
What the results mean
Thermal conductivity
Thermal conductivity measures how readily heat conducts through air when a temperature gradient exists.
Heat-transfer use
Use air thermal conductivity in conduction estimates, insulation gaps, convective correlations, heat exchangers, and equipment heat-loss calculations.
Temperature effect
For dry air, thermal conductivity generally increases as temperature increases.
Assumption
This page assumes dry air at approximately 1 atm. Humidity, gas mixture, and pressure can affect detailed values.
FAQ
Thermal conductivity of air questions
What is the thermal conductivity of air at 15 degrees C?
At 15 °C and 1 atm, dry-air thermal conductivity is approximately 0.0256 W/(m.K).
Does air thermal conductivity increase with temperature?
Yes. For dry air, thermal conductivity generally rises gradually as temperature increases.
Why is air a useful insulator?
Air has relatively low thermal conductivity compared with metals and many solids, especially when trapped so convection is limited.
Related
Air property tables
Density of Air
Air density values for common engineering temperature and pressure lookups.
Dynamic Viscosity of Air
Dynamic viscosity data for air used in fluid dynamics and heat transfer calculations.
Kinematic Viscosity of Air
Kinematic viscosity values for air across practical engineering conditions.
Specific Heat of Air
Specific heat data for air used in thermodynamic and HVAC calculations.