Psychrometric Calculators

Complete psychrometric state point calculator. Enter any two known properties and get all others — dry-bulb, wet-bulb, dew point, RH, humidity ratio, enthalpy, and specific volume.

Calculate dew point temperature from dry-bulb and relative humidity or wet-bulb temperature. Determine condensation risk on surfaces and within wall assemblies.

Calculate wet-bulb temperature from dry-bulb and relative humidity. Required for cooling tower and evaporative cooler sizing. Uses Stull formula for accuracy.

Calculate humidity ratio (specific humidity) in gr/lb or g/kg from dry-bulb temperature and relative humidity. Used in latent load and moisture calculations.

Calculate moist air enthalpy (total heat content) in BTU/lb or kJ/kg. Used for cooling coil energy analysis, heat exchanger sizing, and ventilation energy calculations.

Calculate moist air density from temperature, humidity, and elevation. Essential for fan and duct sizing at altitude — air at higher elevations is less dense and requires larger ducts.

Calculate relative humidity from dry-bulb and dew point, or wet-bulb temperatures. Diagnose comfort complaints and moisture-related building issues.

Calculate mixed air conditions when two airstreams are combined — return air plus outdoor air. Find mixed air dry-bulb, wet-bulb, humidity ratio, and enthalpy.

Analyze cooling coil performance from entering and leaving air conditions. Calculate sensible and latent capacity, SHR, bypass factor, and apparatus dew point.

Calculate heating coil capacity from entering and leaving air conditions and airflow. Determine coil kW or BTU/hr and leaving air temperature for any inlet condition.

Calculate specific volume of moist air in ft³/lb or m³/kg. Convert between mass flow and volumetric flow. Correct fan performance for non-standard air conditions.

Calculate saturation pressure of water vapor at any temperature. Foundation of all psychrometric calculations. Uses ASHRAE equations for high accuracy.

Calculate direct and indirect evaporative cooling effectiveness. Determine leaving air conditions and cooling potential from outdoor wet-bulb and dry-bulb temperatures.

Assess condensation risk on windows, walls, and cold surfaces. Calculate surface temperature below which condensation occurs from indoor air conditions.

Plot air state points on an interactive psychrometric chart. Visualize cooling, heating, humidification, and dehumidification processes from entering and leaving air conditions.

Check whether indoor air conditions fall within ASHRAE 55 comfort zone boundaries. Input dry-bulb temperature and RH to assess thermal comfort in occupied Canadian buildings.

Calculate SHR from psychrometric entering and leaving conditions. Determine the sensible-to-total load split for coil selection and AHU performance analysis.

Calculate the apparatus dew point (ADP) of a cooling coil from entering and leaving air conditions. Verify coil selection and dehumidification performance against design targets.

Calculate coil bypass factor from entering, leaving, and apparatus dew point temperatures. Verify coil contact efficiency and troubleshoot latent performance issues.

Calculate total, sensible, and latent coil load from airflow and psychrometric conditions. Size or verify cooling and heating coils in BTU/hr or kW from entering and leaving state points.

Calculate moisture content of moist air from temperature and relative humidity. Output in lb/lb, g/kg, and gr/lb for latent load calculations and dehumidifier sizing.

Calculate grains of moisture per pound of dry air from relative humidity and temperature. Used in latent load calculations and moisture removal rate sizing across Canadian climates.

Calculate partial vapor pressure and saturation vapor pressure of water vapor in air. Fundamental to all humidity and dew point calculations. Results in kPa, Pa, and inHg.

Calculate absolute humidity in g/m³ or lb/ft³ from dry-bulb temperature and relative humidity. Used in dehumidification design, IAQ analysis, and moisture removal calculations.

Calculate the wet-bulb depression (dry-bulb minus wet-bulb spread) and interpret moisture conditions. A wide depression signals dry air; a narrow spread indicates near-saturation.

Calculate the apparent temperature (feels-like) from air temperature and relative humidity. Based on Environment Canada and NWS heat index formulas used across Canadian provinces.

Calculate the Canadian humidex value from dry-bulb temperature and dew point. Developed by Environment and Climate Change Canada — the official Canadian heat comfort index for summer.

Calculate desiccant dehumidification performance from inlet air conditions and wheel effectiveness. Analyze moisture removal and regeneration energy for low-dew-point HVAC applications.

Full-featured HVAC psychrometric calculator covering all moist air properties in one tool. Input dry-bulb and any second property to get a complete state-point analysis with process diagrams.