Mushroom House Ventilation Calculator
Fresh air exchange for a mushroom fruiting room.
Enter your values
Enter the room area in sq ft.
Enter the ceiling height in ft.
Enter the air exchanges in per hour.
Results update instantly as you type — no submit needed. Your values are remembered on this device, and the shareable link reopens the calculator with exactly these numbers.
- Fresh air exchange
- 120 CFM
- Room volume
- 1,200 cu ft
- Target CO2
- 800-1000 ppm during fruiting (species dependent)
- Humidity note
- Pair with humidification since fresh air lowers RH — target 85-95% RH
Quick answer
Mushroom fruiting rooms need enough fresh air exchange to keep CO2 below about 800-1000 ppm, often requiring 4-8 full air exchanges per hour depending on growing density and species.
CFM = volume x air exchanges per hour / 60
At a glance
| What it does | Fresh air exchange for a mushroom fruiting room. |
|---|---|
| Category | HVAC & Airflow |
| Inputs needed | Room area, Ceiling height, Air exchanges |
| Main output | Fresh air exchange |
| Formula | CFM = volume x air exchanges per hour / 60 |
| Cost | Free — no sign-up, no download |
How to use the Mushroom House Ventilation Calculator
- 1Enter the fruiting room's floor area and height.
- 2Choose an air-exchange rate suited to your mushroom species and density (oyster mushrooms want more than button).
- 3Balance the added fresh air with humidification, since ventilation dries the room.
Inputs explained
- Room area(sq ft)
- Enter the room area in sq ft.
- Ceiling height(ft)
- Enter the ceiling height in ft.
- Air exchanges(per hour)
- Enter the air exchanges in per hour.
Worked example
Using the values the calculator loads with:
Inputs
- Room area150 sq ft
- Ceiling height8 ft
- Air exchanges6 per hour
Results
- Fresh air exchange120 CFM
- Room volume1,200 cu ft
- Target CO2800-1000 ppm during fruiting (species dependent)
- Humidity notePair with humidification since fresh air lowers RH — target 85-95% RH
Frequently asked questions
Why does CO2 matter so much?
High CO2 causes long, thin stems and small caps ('legginess') because mushrooms sense it as a signal to stay underground.
Can I just crack a door?
For small setups yes, but a ducted fan with a timer gives far more consistent, controllable exchange.
What do I need to enter into the Mushroom House Ventilation Calculator?
Just 3 values: room area, ceiling height, air exchanges. Every field starts with a realistic example, so you can change one number at a time and watch the result update instantly.
How does the Mushroom House Ventilation Calculator work out the answer?
Mushroom fruiting rooms need enough fresh air exchange to keep CO2 below about 800-1000 ppm, often requiring 4-8 full air exchanges per hour depending on growing density and species. It applies the formula CFM = volume x air exchanges per hour / 60 and shows the working so you can check each step by hand.
Is the Mushroom House Ventilation Calculator free, and do I need an account?
It is completely free with no sign-up, no download and no usage limit. Everything is calculated in your browser, so the numbers you type never leave your device.
Results are estimates for general information. For medical, legal, structural or financial decisions, confirm with a qualified professional.