What is this? Interactive psychrometric chart for analyzing moist air properties at any elevation. Plot entering and leaving conditions, view all seven psychrometric properties for each, and calculate sensible, latent, and total process loads (BTU/hr and tons), moisture removal, and any reheat. When the process cools and dehumidifies, the loads are taken to the apparatus dew point and the leaving coil condition is shown on the saturation curve. Loads use standard air corrected for elevation, or the entering air's actual density.
How to use Set your site elevation, then hover over the chart to read air properties in real time. If you want to calculate sensible, latent, and total process loads between two points, enter CFM and click to pin entering and leaving state points. When the process cools and dehumidifies, the leaving coil point appears as well; click near it or edit its tiles to change the leaving air's moisture while its dry bulb stays put. Alternatively, click any two property tiles to enter values directly — any two independent properties define the state, and the two most recently entered are used. Loads use standard air corrected for elevation by default; choose Entering Air when your CFM is the actual airflow at the entering condition.
Elevation (ft)
14.696 psia
CFM
Airflow in CFM — required for process loads
Air Density Basis
Standard for rated or standard airflow; Entering Air for actual airflow, especially high outdoor air
2030405060708090100110120025507510012515017520010%20%30%40%50%60%70%80%90%100%Dry Bulb Temperature (°F) Humidity Ratio (gr/lb) Relative Humidity Wet Bulb Temperature Enthalpy Specific Volume
Elevation: 0 ft (14.696 psia)
Process Loads

Enter CFM to view process loads.

Entering Air Conditions
Click any tile to enter a value.
Dry Bulb

—°F

Wet Bulb

—°F

Dew Point

—°F

Relative Humidity

—%

Humidity Ratio

—gr/lb

Enthalpy

—BTU/lb

Specific Volume

—ft³/lb

Leaving Air Conditions
Click any tile to enter a value.
Dry Bulb

—°F

Wet Bulb

—°F

Dew Point

—°F

Relative Humidity

—%

Humidity Ratio

—gr/lb

Enthalpy

—BTU/lb

Specific Volume

—ft³/lb

Leaving Coil Conditions
Dry Bulb

—°F

Wet Bulb

—°F

Dew Point

—°F

Relative Humidity

—%

Humidity Ratio

—gr/lb

Enthalpy

—BTU/lb

Specific Volume

—ft³/lb

What is a psychrometric chart?

A psychrometric chart is a graphical representation of the thermodynamic properties of moist air at a constant pressure. It plots the relationships between dry bulb temperature, wet bulb temperature, dew point temperature, relative humidity, humidity ratio, enthalpy, and specific volume. HVAC engineers use psychrometric charts to analyze air conditioning processes such as heating, cooling, humidification, dehumidification, and mixing of airstreams. Each point on the chart represents a unique air state defined by any two independent properties. The chart is essential for understanding how air treatment processes move air from one state to another and for verifying that system designs will achieve the desired indoor conditions.