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Greenhouse Fans


Greenhouse fans are an essential component of any greenhouse, helping create an ideal environment that fosters plant growth. By regulating climate, cooling the greenhouse, and relieving thermal stress they help ensure plants reach their maximum potential and grow to their fullest potential. Select the best Greenhouse Ventilation Exhaust Circulation Fans.

This fan system works effectively for smaller greenhouses. The inflation of perforated plastic tubes at one end wall’s ridge draws air through an adjustable motorized louver and pulls in air through an intake duct system.


Greenhouse fans serve a purpose beyond mere ventilation: They circulate and move air around a greenhouse to help regulate summer temperatures, maintain relative humidity levels throughout winter months, and ensure adequate CO2 concentrations for plant respiration. Ventilation also aids evaporative cooling by permitting plant transpiration to contribute to air movement within a greenhouse environment.

Greenhouse fans come in various sizes to meet your growing needs. Their size depends on the volume of greenhouse space in square feet and the desired summer cooling effect; capacity measurements are typically listed in manufacturer catalogs as cubic feet per minute (CFPM).

If a fan size isn’t properly selected for a greenhouse, it won’t provide adequate cooling or circulation, while too-large fans could make the environment too windy, potentially leading to plant damage due to excessive wind movement.

Fans should be regularly cleaned to reduce dust accumulation on blades and housing. Furthermore, any weeds or grasses growing near shutters must be removed in order to allow air flow through both exhaust and intake louvers. These louvers must close securely when your fan is off; otherwise, heat loss during winter months could become severe and significantly increase utility bills.

For optimal ventilation in poly covered houses, intake louvers should measure at least 1 1/4 times fan area. A continuous louver is preferable over several smaller louvers as this ensures it doesn’t become blocked by doors or open cracks; motorized dampers or solenoids connected to the thermostat that operates the fan can operate these intake louvers efficiently.

Greenhouse fans require routine maintenance in order to function optimally. Blades should be regularly brushed clean, the motor checked to make sure it’s operating efficiently, the thermopile inspected to prevent overheating or slipperiness and the thermostat rechecked to make sure there is not a wide difference between on/off positions.

Temperature Control

Greenhouse fans provide temperature regulation by introducing cool air into and replacing warm greenhouse air with cooler air from outside, maintaining an ideal environment for plants while controlling carbon dioxide production by plants thereby decreasing fungal diseases in the greenhouse environment.

Ventilation systems can also help control humidity levels by moving air from areas with higher moisture to those with lower humidity, thus dissipating it and decreasing humidity levels. When this air is circulated, moisture dries off, decreasing humidity. Fans can be used to control temperatures by keeping hot air from rising in greenhouses on sunny days to prevent excessive heat build-up and buildup.

Proper ventilation of a greenhouse requires having the appropriate size fan. Capacity can be determined by multiplying your floor area of the greenhouse by the number of hours daily you want the fan running; fan sizes should provide at least one air change per minute during summer cooling purposes.

To ensure the fan is providing enough airflow, static pressure must be measured and recorded. You can obtain this information from your greenhouse equipment supplier and find it in its performance data. Static pressure should not exceed 0.06 inches of water.

An air moving fan designed to move 10,000 cubic feet per minute must be capable of moving that volume at a static pressure of 0.06 inches of water, to account for potential variations in greenhouse environments. When selecting such a fan, ensure it can provide airflow at a higher static pressure than anticipated; that will provide greater room for fluctuations.

Common errors that reduce the efficiency of a greenhouse fan include louvers that don’t open correctly when the fan turns on. Installing motorized louvers that open together should improve efficiency; their opening should ideally cover an area equivalent to 1.7 square feet per 1000 cubic feet per minute of fan capacity in poly-covered greenhouses.

Humidity Control

Greenhouse fans help maintain consistent humidity levels to prevent fungal disease outbreaks, providing a constant source of fresh air to keep plant surfaces dry and prevent condensation.

Fans with thermostats that can be set to turn on and off according to a desired temperature or humidity range help greenhouse growers ensure consistent growing conditions and avoid fluctuations in humidity levels. When selecting the ideal fan for your greenhouse, be sure to consider its size as well as how much air needs to be moved each minute; for optimal results, its power should be at least two times greater than your square footage for a steady supply of fresh air.

To keep a greenhouse environment safe and comfortable, ventilation fans must be properly maintained and regularly inspected for signs of potential issues. Some common issues include improper lubrication (be sure to follow manufacturer recommendations), weeds blocking the fan, or electrical wiring issues; an experienced technician should inspect your ventilation system and offer recommendations for repairs or replacements that will maximize its performance.

One effective method of increasing humidity in greenhouse walls is by using a fan and pad system integrated with them. A series of exhaust fans are installed at one end while water circulates through porous pads at the other, collecting heat from solar radiation and plants as it passes over wetted pads before being evaporated off by fans and then forced through vents to push air through.

Fans are an effective tool for climate control in more direct ways, too, by offering a cooling effect. Fans may be placed along the roof ridge or above doors in unison to reduce the temperature in a small house that does not remain tightly sealed, providing enough climate regulation.

Fans are an effective solution for large greenhouses to supplement or replace the prevailing heating/cooling system, either supplementing it or acting as a stand-in. Most often, fans should be on a timer so they turn off when the heater kicks on to prevent both systems from operating simultaneously. You could set them for just a few minutes at the beginning of each cycle before shutting them off to allow the heater to bring the air temperature up as needed.

Noise Control

Air circulation plays a pivotal role in greenhouse operations. By employing high-capacity fans in an energy management system that monitors environmental factors and optimizes plant growth while conserving energy inputs, robust, cost-effective, and sustainable operations are possible.

Greenhouse fans offer numerous advantages to greenhouse facilities, but one key benefit is their ability to reduce noise levels. This is particularly evident with energy-efficient fans using advanced motors and blade designs for improved sound reduction. Furthermore, their quiet operation creates an enjoyable work environment for staff members.

Greenhouse fan performance can be gauged using CFM (cubic feet per minute) ratings, which measure how much air can be moved by one fan at full capacity in one minute. These ratings should be considered alongside greenhouse size to ensure adequate air movement; fan spacing depends upon its dimensions to achieve optimal circulation of airflow.

To optimize the efficiency of high-capacity greenhouse fans, consider including an energy recovery ventilator (ERV). An ERV enables growers to pre-condition incoming air by recovering heat from existing air exhaust. This process reduces energy expenditures significantly while simultaneously maintaining climate consistency, increasing yield, and aiding pollination for self-pollinated crops.

Solar power can further contribute to the sustainability of greenhouse fans by dramatically cutting energy costs while creating an eco-friendly solution to ventilation in greenhouses.

Contact a Bluelab specialist immediately for more information on the benefits of high-capacity greenhouse fans or to discuss your unique needs.

Hi-capacity greenhouse fans can make all the difference for the success of your crop. By selecting appropriate fans for your greenhouse structure and maintaining regular repairs and maintenance, you can ensure a safe growing environment that benefits all workers involved. Contact us now to discover how our state-of-the-art Multifan Greenhouse Fans can make a difference in your operation; our selection ranges from energy-saving 3,000 CFM models up to powerful 4,000 CFM versions for any budget imaginable!