Dehumidifier sizing calculator
Water in equals water out: nearly every liter you feed a grow room comes back as vapor, and everything a drying harvest loses ends up in the air. Match removal capacity to that load or RH drifts up every day.
Moisture load
Result
Includes a 1.3× real-world safety factor
Pint ratings (AHAM) are measured at 80 °F / 60% RH; in a cooler room or at a lower RH setpoint the same unit removes much less, which is what the 1.3× factor covers. If your AC runs constantly it also removes water; this sizing treats the dehumidifier as doing all the work.
Not sure what RH you should hold? Find your VPD target →
How do you size a dehumidifier for a grow room?
Estimate pints-per-day capacity from how much water your plants transpire, roughly equal to what you feed them, plus moisture gained through air exchange, then add a safety margin in humid climates. A drying room instead needs capacity sized off wet harvest weight, since freshly cut plants release most of their moisture in the first week. Enter your room and grow details above for an exact target.