Horizontal Airflow using EOS 450 air circulators (internal greenhouse fans) from Megatherm is the best solution for air circulation inside greenhouses.
Understanding the Fundamentals
The principle behind Megatherm’s air circulation system is based on the idea that air, when moving in a consistent horizontal pattern within a closed space like a greenhouse, requires very little energy to overcome friction and stay in motion. In other words, it just needs a gentle “push.”
This airflow is achieved by installing the correct number of EOS 450 air circulators in the right configuration, maintaining effective air movement throughout the greenhouse.
Uniform Conditions Inside the Greenhouse
Before the development of Horizontal Airflow Fan (HAF) systems, it was common to observe temperature differences of 7°C to 10°C between opposite ends of a greenhouse during the night. Plant growth and quality often reflected this inconsistency.
Today, with a properly installed air circulation system, the temperature difference should not exceed 2°C anywhere in the greenhouse.
Uniform temperature and environmental conditions lead to more consistent and optimized crop production.
Reduction of Plant Diseases
In addition to providing uniform temperatures, horizontal airflow fan systems can significantly reduce the occurrence of plant diseases.
At night, when leaf temperature drops significantly below the air temperature, it can reach the dew point, resulting in moisture forming on the leaf surface—the perfect environment for disease development.
Air movement removes this surface moisture, creating a drier microclimate that inhibits disease.
Improved Plant Growth
During the day, photosynthesis depletes the carbon dioxide (CO₂) in the thin layer of air next to the leaf surface.
Moving air replaces this depleted air with fresh air richer in CO₂, allowing the plant to “feed” more efficiently and thereby supporting better growth.
24-Hour Operation
To be effective, the air circulation system should operate 24 hours a day, except when the side exhaust fans of the greenhouse are in operation.
Megatherm provides an electrical control panel for managing the air circulators, and it can also be integrated with the greenhouse’s Clima system.
The operating cost of the fans is negligible compared to the benefits of disease reduction and production optimization.
