Balance humidity, heat, and stale air quickly. Choose metrics, set targets, and compare fan options. Generate reports, export files, and plan installs confidently today.
Enter enclosure dimensions, choose airflow targets, and optionally estimate energy and cost.
| Scenario | Size | ACH | Fan Rating | Loss% | Density | Fans Needed |
|---|---|---|---|---|---|---|
| Small tunnel | 6×3×2.4 m | 10 | 2500 m³/h | 10 | Medium | 1 |
| Dense canopy | 10×4×3 m | 12 | 3000 m³/h | 15 | High | 2 |
| Shade structure | 25×12×10 ft | 8 | 1800 CFM | 12 | Medium | 2 |
Circulation planning starts with a realistic ACH target. For seedling trays, 6–10 ACH typically keeps humidity stable while avoiding leaf flutter. Vegetative growth often benefits from 10–15 ACH to reduce boundary-layer resistance and improve transpiration control. Fruiting crops with dense canopies may require 12–20 ACH to prevent stagnant pockets around flowers and developing fruit. Aim for 0.2–0.5 m/s near canopy.
The calculator multiplies enclosure volume by the selected ACH to estimate base airflow. A 6×3×2.4 m tunnel holds 43.2 m³, so 10 ACH equals 432 m³/h before adjustments. In imperial units, airflow is expressed as CFM, calculated from cubic feet per hour divided by 60. This aligns fan selection with manufacturer airflow ratings.
Real installations rarely deliver nameplate airflow. Screens, guards, and bends can reduce flow by 5–20%, so a loss allowance helps protect performance. Insect netting or carbon filters may justify 20–35% allowance. Plant density adds mixing demand; the built-in factors (Low 1.00, Medium 1.15, High 1.30) reflect increasingly obstructed air paths. A 1.10–1.25 safety factor is useful for summer peaks and aging motors during hot, humid spells.
Use the per-fan rating and efficiency field to reflect actual delivered airflow. If a fan is rated at 2500 m³/h but operates at 0.85 efficiency, the calculator treats it as 2125 m³/h. Multiple smaller fans can improve uniformity versus one large unit, especially in long tunnels. As a practical spacing rule, place circulation fans about every 6–10 m, alternating sides when possible. Aim airflow along the canopy, avoid direct blasts at tender stems, and stagger fans to reduce dead zones.
Power and run time estimates help compare options. Two 120 W fans running 8 hours consume 1.92 kWh/day, or about 57.6 kWh/month. At a rate of 0.20 per kWh, that is roughly 11.52 per month. For round-the-clock operation, multiply daily kWh by 3.0. These quick benchmarks support budgeting, and they highlight how improving distribution can reduce total fan count without sacrificing crop comfort.
Most small structures perform well between 8 and 15 ACH. Start near 10 ACH, then increase if you see condensation, persistent hotspots, or weak stem movement. Reduce if leaves show constant flutter or drying.
Guards, insect screens, ducts, and obstructions reduce delivered airflow. The loss percent adds a cushion so the installed system still meets the target airflow after real-world restrictions.
You can, but exhaust fans are designed for air exchange, not mixing. If the exhaust fan will run continuously, include its airflow as one option. Otherwise, use dedicated circulation fan ratings for more uniform canopy movement.
If you have test data, use it. Otherwise, 0.75–0.90 is a practical range for many fans once mounted with guards and typical restrictions. Lower values are safer for dense canopies or screened intakes.
No. It estimates circulation fan count for mixing and uniformity. Ventilation also depends on outside conditions, heat loads, vents, and exhaust sizing. Use this result as a planning baseline before final equipment selection.
Improve airflow paths, reduce obstructions, and place multiple smaller fans for uniform mixing. Check that airflow is aimed along the canopy, not into walls. Efficient fans and timed operation during peak humidity can cut kWh significantly.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.