Psychrometric Calculator

The Psychrometric Calculator determines all air properties from any two known parameters. This comprehensive tool is essential for HVAC design, air conditioning analysis, and building environmental control systems.

Modify the values and click the calculate button to use
Input Method
Dry Bulb Temperature °C
Relative Humidity %
Temperature Unit  
Atmospheric Pressure kPa
Altitude m

Related Relative Humidity Calculator | Dew Point Calculator | Wet Bulb Calculator

Understanding Psychrometrics

Psychrometrics is the study of the thermodynamic properties of moist air. It deals with the relationships between temperature, humidity, pressure, and energy content of air-water vapor mixtures.

Key Psychrometric Properties

Temperature Parameters

Humidity Parameters

Energy Parameters

Volume Parameters

Psychrometric Processes

Sensible Heating/Cooling

Temperature change with constant humidity ratio (horizontal line on psychrometric chart)

Humidification

Adding moisture at constant dry bulb temperature (vertical line)

Dehumidification

Removing moisture, often with cooling below dew point

Evaporative Cooling

Cooling with moisture addition at constant wet bulb temperature

Mixing

Combining two air streams with different properties

HVAC Applications

System Design

Process Analysis

Industrial Applications

Manufacturing Processes

Environmental Control

Calculation Methods

Fundamental Equations

Humidity Ratio: W = 0.622 × (Pv / (P - Pv))

Enthalpy: h = 1.006 × T + W × (2501 + 1.86 × T)

Specific Volume: v = 0.287 × (T + 273.15) × (1 + 1.608 × W) / P

Relative Humidity: RH = (Pv / Pvs) × 100

Psychrometric Chart

The psychrometric chart is a graphical representation of air properties:

Comfort Applications

Human Comfort Zone

Comfort Indices

Energy Considerations

Cooling Load Components

System Efficiency

Measurement and Instrumentation

Temperature Measurement

Humidity Measurement

Note: Psychrometric calculations assume standard atmospheric pressure unless otherwise specified. For high altitude applications, pressure corrections are essential for accuracy.