🌬️ Complete Grow Tent Ventilation Calculator
Calculate optimal intake and exhaust fan sizes for your grow space. Perfect your complete ventilation system for healthier plants and better yields. Tools for cannabis growers and indoor gardeners.
💨 Exhaust Fan Sizing Calculator
Calculate the optimal exhaust fan CFM for your grow space based on lighting, plants, and environmental needs.
🌡️ Grow Space Parameters
📋 Recommended Exhaust CFM
⚡ Sizing Guidelines by Application
20-30 air changes/hour
Low heat, minimal odor
30-40 air changes/hour
Moderate heat load
40-60 air changes/hour
High heat generation
60+ air changes/hour
Maximum control needed
🌡️ Heat Load Calculation
Lighting Heat Factor: Different lights produce different heat loads. LEDs: ~30% heat, CMH: ~50% heat, HPS: ~85% heat. Our calculator automatically adjusts CFM based on your lighting choice and wattage.
🌱 Plant Transpiration
Humidity Management: Plants release moisture through transpiration. More plants = more humidity. The calculator adds CFM based on plant count to maintain proper humidity levels and prevent mold/mildew.
🔄 Air Changes Explained
Why Air Changes Matter: Air changes per hour (ACH) measure how often your tent's air is completely replaced. 30 ACH = minimum, 40-60 ACH = optimal for most grows, 60+ ACH = high-performance setups.
🌡️ Temperature Differential
Outside vs Inside Temp: Larger temperature differences require more airflow. If outside air is 70°F and you want 78°F inside, you need less CFM than if outside is 85°F.
🔲 Filter Impact
Carbon Filter Sizing: Filters reduce airflow by 20-40%. Heavy-duty filters need more CFM compensation. Always size your fan to overcome filter restriction while maintaining target airflow.
📏 Safety Margin
Why 25% Extra: Environmental conditions change, filters get dirty, and you may expand your setup. A 25% safety margin ensures your fan can handle peak loads and aging equipment.
🌬️ Intake Fan Sizing Calculator
Size your intake system to complement your exhaust fan and create optimal airflow patterns.
💡 Tip: The exhaust CFM automatically updates from the exhaust calculator above, or you can set it manually.
🎯 System Parameters
📋 Calculated Results
🎯 Optimal Sizing Rules
Passive Intake: 2-3x larger area than exhaust outlet. This creates proper negative pressure while maintaining smooth airflow. For 200 CFM exhaust, aim for 50-75 square inches of intake area.
🌡️ Temperature Management
Cool Air In, Hot Air Out: Position intake low and exhaust high to work with natural convection. This reduces fan workload and creates even temperature distribution throughout your grow space.
💨 Velocity Control
Keep It Quiet: Intake velocity under 5 ft/sec minimizes noise and turbulence. Higher velocities create whistling sounds and reduce efficiency. Our calculator optimizes for 3-4 ft/sec.
🔧 Installation Tips
Position Matters: Place intake on opposite wall from exhaust, as low as possible. Use round intakes when possible - they're 15% more efficient than square openings of equal area.
📊 Pressure Balance
Negative Pressure Benefits: Maintains -0.5 to -1.0" prevents air leaks and odor escape. Too much negative pressure overworks fans; too little allows uncontrolled air movement.
🔄 Filter Considerations
Plan for Restriction: Filters reduce airflow by 20-40%. Our calculator automatically adjusts intake size to compensate for your chosen filtration level while maintaining optimal performance.
⚡ Quick Reference: Exhaust & Intake Sizing
Common exhaust fan sizes and recommended intake diameters for optimal performance