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Selecting Greenhouse Fans for Optimal Air Flow

Selecting Greenhouse Fans for Optimal Air Flow

Though your greenhouse will help you extend the growing season, you still must monitor and maintain optimal growing conditions inside as the temperatures change outside. Selecting greenhouse fans for your structure will help optimize air flow and maintain your growing environment. 

Your plants will thrive in an environment where the temperature, humidity and air quality is controlled, and that starts with proper ventilation, both natural and automatic.

Fans are a common automated ventilation option. But using them to help create an ideal environment isn’t as simple as just installing them and turning them on.

To create the most successful conditions for your plants, you should keep these suggestions in mind when selecting fans for optimal air flow.

Choosing a Greenhouse Fans

When selecting fans, consider their efficiency. For example, circulating fans with blades that operate against zero static pressure are more efficient than exhaust fans designed to force air. Look for high-efficiency fans because they will carry a heavy workload. Fans with efficiencies of 14 to 16 are about average; better fans have efficiencies of 18 or higher. Tall plants and hanging baskets will reduce air flow, but fans with shrouds will help spread the flow of air over a greater distance.

Selecting Your Fan Layout

There are two types of layouts you can choose for your greenhouse fans, parallel or series. In a parallel layout, all fans are located at one end of the greenhouse and the air is pulled back, creating a loop. A series layout features fans in an alternating pattern, moving in toward the center. Because greenhouses may vary in size or sit on uneven land, a series layout prevents fluctuations in heat or cold collecting in the higher or lower points.

Determining Fan Location

Locate fans near the center of the air mass that they are helping to move. For example, in greenhouses with floor or bench crops, place fans seven feet to eight feet above the floor. Fans sitting above or below hanging baskets circulate air with little resistance. This will also prevent foliage from drying out by getting too much direct air.

Controlling Air Flow

Ideally, fans move air evenly throughout the greenhouse to help create the controlled environment you want for your plants. To do this, make sure that plants aren’t blocking air flow. Instead, generate a momentum of flow with the installation of multi-speed fans that are managed by a thermostat.

Directing Air Flow

Achieving horizontal air flow has long been a popular concept in greenhouse management. In recent years, vertical fans have gained more interest. Though they do level out temperatures from top to bottom, vertical fans don’t have the same effect across the entire growing area, which creates inconsistencies in plant growth. Horizontal fans are still prized for their ability to move air evenly and promote the movement of water through plants for their optimal health. 

Maintaining Your Performance

Simple preventive maintenance can help improve the flow of air in your greenhouse. Clean fan blades and the motor frequently to reduce dirt and dust buildup and prevent overheating. Inspect belts, particularly if you hear squeals and squeaks on startup. Replace belts with any cracks or frayed edges. Also check to see that fans hang securely in place with brackets or chains to keep them from moving out of place.

We can help you select the fans you need for your greenhouse application. Call us at 1-800-531-4769 or visit!