Humidifier Sizing
Work out the humidifier output your fruiting chamber needs to hold its target humidity — from the chamber's volume, how much fresh air you exchange, and the species' targets.
Every air change swaps humid chamber air for drier room air, and the humidifier has to replace that lost moisture. The calculator works it out from the absolute-humidity deficit — the real physics, not a rule of thumb — and gives the output in millilitres per hour and litres per day, plus a suggested unit class. A leaky chamber needs more; a tightly sealed one, less.
Every air change swaps humid inside air for drier room air; the humidifier replaces that lost moisture. Figures assume a reasonably sealed chamber — a leaky one needs more, a tightly closed one less.
How to use it
- Pick your species. It sets the target temperature and humidity, and a default air-exchange rate.
- Enter the chamber volume. In litres — the Chamber Sizing tool gives you this figure.
- Set air changes per hour. How often fresh air replaces the chamber's air.
- Enter your room air. Temperature and humidity of the room the chamber draws from, and read the output needed.
Questions
How big a humidifier do I need for mushrooms?
It depends on the chamber's volume, how much fresh air you exchange, and the target humidity. The calculator gives the output in mL per hour and litres per day, and suggests a unit class.
What is absolute humidity?
The actual mass of water in the air, in grams per cubic metre. The humidifier replaces the difference between your target and the drier room air it pulls in.
Why does fresh air increase the humidifier need?
Every air change swaps humid chamber air for drier room air, and the humidifier has to re-humidify it. High fresh-air exchange usually drives the demand.
Can I just mist by hand instead?
For a small grow, yes. A sealed chamber with real fresh-air exchange needs continuous output — that's where a sized humidifier comes in.