Free online tool to calculate mixed air conditions instantly. Mix return air and outside air to find the exact temperature, humidity ratio, and enthalpy. No sign-up required.
Mixed air is like pouring hot and cold water into a single bucket. It calculates the final temperature when outdoor fresh air meets indoor return air.
Stream 1 fraction must be a dry-air mass-flow fraction (not volumetric or damper %). Convert volumetric flow to mass using density if needed. Humidity ratio uses P=1013.25 hPa.
Rule of Thumb: The mixed air temperature is a weighted average of return air and outside fresh air.
Checklist: Enter Stream 1 and Stream 2 conditions. Set the mass-flow fraction. Read the resulting mixed state.
Quick Tip: In freezing weather, ensure the mixed air temperature stays above 5°C (41°F) to prevent frozen coils.
Mixed air is the combination of return air from the building and outside fresh air, mixed in the air handling unit before being conditioned.
It is calculated using the mass flow rates and temperatures of the two individual air streams. Our calculator performs this mass balance equation automatically.
Knowing the mixed air conditions is essential to determine the actual cooling or heating load the HVAC coil must handle.
Yes, by calculating the mixed air temperature and enthalpy under various outside air fractions, you can determine the optimal economizer setpoints and maximize free cooling efficiency in your building.