Grain EMC & Fan Run Calculator
Enter your ZIP for live conditions, or type your own numbers to run what-if scenarios. Find out whether running your fan will dry the grain toward target — or put moisture back in.
Run the fan
What-if table — EMC at other temperatures & humidities
Equilibrium moisture content (% wet basis) for corn, shown at plenum conditions (ambient air plus 4°F of fan heat), compared against your 15.0% target.
How this works
Equilibrium moisture content (EMC) is the moisture level your grain will drift toward if you keep pushing a given air condition through it. If the EMC of the air is below your target, the fan dries. If it is above, the fan puts moisture back in.
Fan heat matters. A running fan adds heat to the air without adding any water. Warmer air at the same water content has a lower relative humidity, so plenum air is always drier than the air outside. This calculator computes the humidity ratio of the ambient air, raises the temperature by the fan's heat of compression, then re-solves relative humidity at the higher temperature before calculating EMC. That is why a 50°F, 80 % RH morning can still be a solid drying window.
Equations. EMC uses the modified Henderson equation with ASABE D245.6 constants for each grain, converted from dry basis to wet basis. Psychrometrics use the Magnus formulation for saturation vapour pressure, adjusted for barometric pressure at your elevation.
Weather is pulled live from the Open-Meteo forecast service using coordinates resolved from your ZIP code. Every value stays editable, so you can override any number to test a scenario.
For general guidance only. Actual results vary with grain condition, foreign material and fines, bin loading, airflow uniformity, initial moisture variation, and changing weather. This tool does not replace regular bin inspection, moisture testing, or the advice of a qualified grain-conditioning professional. Always follow safe bin entry and equipment procedures. © HTS Ag — High Tech Solutions for Agriculture.
Grain EMC & Fan Run Calculator
Enter your ZIP for live conditions, or type your own numbers to run what-if scenarios. Find out whether running your fan will dry the grain toward target — or put moisture back in.
Run the fan
What-if table — EMC at other temperatures & humidities
Equilibrium moisture content (% wet basis) for corn, shown at plenum conditions (ambient air plus 4°F of fan heat), compared against your 15.0% target.
How this works
Equilibrium moisture content (EMC) is the moisture level your grain will drift toward if you keep pushing a given air condition through it. If the EMC of the air is below your target, the fan dries. If it is above, the fan puts moisture back in.
Fan heat matters. A running fan adds heat to the air without adding any water. Warmer air at the same water content has a lower relative humidity, so plenum air is always drier than the air outside. This calculator computes the humidity ratio of the ambient air, raises the temperature by the fan's heat of compression, then re-solves relative humidity at the higher temperature before calculating EMC. That is why a 50°F, 80 % RH morning can still be a solid drying window.
Equations. EMC uses the modified Henderson equation with ASABE D245.6 constants for each grain, converted from dry basis to wet basis. Psychrometrics use the Magnus formulation for saturation vapour pressure, adjusted for barometric pressure at your elevation.
Weather is pulled live from the Open-Meteo forecast service using coordinates resolved from your ZIP code. Every value stays editable, so you can override any number to test a scenario.
For general guidance only. Actual results vary with grain condition, foreign material and fines, bin loading, airflow uniformity, initial moisture variation, and changing weather. This tool does not replace regular bin inspection, moisture testing, or the advice of a qualified grain-conditioning professional. Always follow safe bin entry and equipment procedures. © HTS Ag — High Tech Solutions for Agriculture.