Sensible heat
Q = m x Cp x Delta T
Cp at constant pressure
Air property calculator
Specific Heat of Air Calculator
Calculate specific heat at constant pressure for dry air, with values reported for thermal and HVAC calculations.
Instant air heat-capacity solver
Enter air temperature
Results update automatically using interpolated dry-air Cp values at 1 atm. Use Celsius, Fahrenheit, or Kelvin.
Calculated result
Formulas
Specific heat formulas and conversions
Common conversions
1 J/(kg.K) = 0.000238846 Btu/(lb.deg F)
1 kJ/(kg.K) = 1000 J/(kg.K)
K = degrees C + 273.15
The calculator linearly interpolates tabulated dry-air specific heat values at standard atmospheric pressure. Cp changes slowly near room temperature, but higher-temperature systems should use data for the actual gas mixture.
Reference table
Specific heat of air reference table
| Temperature (°C) | Specific heat, Cp (J/kg.K) |
|---|---|
| -20 | 1003 |
| -10 | 1004 |
| 0 | 1004 |
| 10 | 1005 |
| 15 | 1005 |
| 20 | 1005 |
| 25 | 1005 |
| 30 | 1006 |
| 40 | 1007 |
| 50 | 1008 |
| 60 | 1009 |
| 70 | 1010 |
| 80 | 1011 |
| 90 | 1012 |
| 100 | 1013 |
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
Specific heat
Specific heat at constant pressure is the energy required to raise the temperature of one kilogram of air by one kelvin while pressure remains constant.
HVAC use
Cp is used in heating and cooling load estimates, air-side energy balances, ventilation calculations, and heat-exchanger checks.
Temperature effect
Near ordinary HVAC temperatures, dry-air Cp changes slowly, so 1005 J/(kg.K) is a common quick-reference value.
Assumption
This page assumes dry air. Moist air and combustion gases require mixture-specific heat capacity values.
FAQ
Specific heat of air questions
What is the specific heat of air at 15 degrees C?
At 15 °C and 1 atm, dry-air specific heat at constant pressure is approximately 1005 J/(kg.K).
Is Cp for air constant?
Cp is often treated as constant for quick room-temperature calculations, but it varies with temperature and gas composition.
What formula uses specific heat of air?
A common sensible-heat formula is Q = m x Cp x Delta T.
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.
Thermal Conductivity of Air
Thermal conductivity values for air used in heat transfer checks.