Enter dry-bulb temperature and relative humidity to get dew point, wet-bulb, humidity ratio, enthalpy, vapour pressure and specific volume (sea-level, 101.325 kPa).
°C
% (0–100)
Dew point
—
Wet-bulb temp
—
Humidity ratio
—
Enthalpy
—
Vapour pressure
—
Specific volume
—
Assumptions: barometric pressure 101.325 kPa; saturation pressure by Magnus formula; enthalpy h = 1.006·T + W·(2501 + 1.86·T) kJ/kg dry air.
Why psychrometrics matter for heat recovery
Dew point tells you where condensation starts in a plate exchanger (frost/condensate risk in cold make-up air). Enthalpy and humidity ratio are what an enthalpy wheel actually recovers — sensible plates only move the temperature term. Use this alongside the savings calculator to decide plate vs rotary.
Frequently asked questions
What is dew point?
The temperature at which air becomes saturated (100% RH) and water starts to condense. Below it, a cold surface fogs or frosts.
When do I need wet-bulb?
Wet-bulb drives evaporative cooling and indirect evaporative cooling (data centers, cooling towers) — the lowest temperature achievable by evaporation alone.
Does this include altitude?
No — it assumes sea-level pressure. At altitude, lower pressure raises specific volume; for high sites use a full psychrometric chart.
Indicative values for preliminary design only. Zibo Qiyu uses project-specific psychrometrics for final exchanger sizing — talk to an engineer.