The Greenhouse Circulation Fan is vital to healthy plants in your greenhouse. They reduce heat stress and improve air quality. This is done by a gentle “racetrack” air pattern which mixes the air from the ceiling to the floor. You need to maintain air circulation so that temperatures remain uniform throughout the greenhouse during the winter when the greenhouse is heated.
Features of Greenhouse Circulation Fan
Without air mixing fans, the warm air rises to the top and the cool air settles around the plants on the floor. Also, a greenhouse circulation fan will help to eliminate hot and cold spots in corners. Fans help to maintain uniform temperatures, and will reduce heating costs up to 5%. Fans also prevent mildew and plant diseases by reducing the humidity within the plant canopy. Carbon dioxide utilization is also improved, a basic necessity for healthy plants.
Small fans with a cubic foot per minute air moving capacity equal to one quarter of the air volume of the greenhouse are sufficient. For small greenhouses, place the fans in diagonally opposite corners. If you have a larger greenhouse, you may need to place circulation fans at the halfway mark of the length. Also, you may need to place 4 across on the width. For most hobby greenhouses, one in each corner will be sufficient. Turn the circulation fans off during the warmest summer months when the greenhouse will be needed to be ventilated. An often overlooked item, the greenhouse circulating fan is a small investment for healthy plants.
These are also often referred to as HAF fans, horizontal air flow fans.