Healthcare & Pharmaceutical TAB Specialists
AABC / CAABC Certified

Engineering Utility

Psychrometric Calculator

Fast psychrometric calculations for TAB and HVAC work. Enter dry-bulb temperature with either relative humidity or dew point to compute humidity ratio, moisture content, wet-bulb temperature, enthalpy, and specific volume.

Uses standard atmosphere (101.325 kPa) by default SI / IP inputs · SI + IP outputs
Sample Condition Within Comfort Band
Dry-Bulb (°C)
23.0
Relative Humidity (%)
50.0
Dew Point (°C)
12.0
Wet-Bulb (°C)
16.2
Humidity Ratio (kg/kg)
0.0087
Enthalpy (kJ/kg)
45.4

Calculations approximate standard psychrometric relationships. For critical engineering design, always confirm against project standards.

Psychrometric Inputs

Assumes constant pressure and thermodynamic equilibrium.

Unit System

Input Combination

°C
%
kPa

Optional. Leave at 101.325 kPa (or 29.92 inHg) for standard atmosphere.

Uses standard psychrometric relationships with a Tetens-type saturation pressure approximation. Intended for field checks and diagnostics, not as a substitute for project-specific design software.

Calculated Properties

All per kilogram or pound of dry air as noted.

Relative Humidity

%

Dew Point

°C

Wet-Bulb (approx.)

°C

Humidity Ratio

kg water / kg dry air

Moisture Content

g water / kg dry air

Enthalpy

kJ / kg dry air

Specific Volume

m³ / kg dry air

Specific Volume (IP)

ft³ / lb dry air

Quick Interpretation

Run a calculation to see a brief interpretation of the condition – comfort band, dehumidification required, or risk of condensation.

Psychrometrics in the Field

Psychrometric data is the foundation of almost every HVAC diagnostic. This tool provides fast field-level values—humidity ratio, dew point, wet-bulb temperature, enthalpy, and specific volume—without needing a chart or app.

Moisture Load

Identify whether the space requires dehumidification, humidification, or adjustments to OA mixtures.

Cooling Coil Performance

Compare entering/leaving air conditions, evaluate approach temperatures, and verify sensible/latent behavior.

Outdoor Air Evaluation

Understand how outside conditions affect pressurization, mixed air temperature, and equipment capacity.

Ventilation Troubleshooting

Confirm if high supply humidity, elevated dew points, or poor latent removal are contributing to comfort or condensation issues.

TAB Verification

Validate sensor readings, check mixed-air calculations, and confirm that measured airflow and temperature data align with expected thermodynamic behavior.