Maintain consistent greenhouse temperatures with a thermostatically controlled shutter fan. Simply set the temperature and the system will do the rest! This shutter fan can be used with virtually any greenhouse! No matter how big or small your greenhouse is, air circulation and ventilation is critical to the well being of your plants. The 12" shutter fan is quiet and corrosion resistant, UV protected and maintenance free. Place the intake on the end wall opposite the shutter fan. When the fan turns on, the thermostat also opens the shutter to supply fresh air in and stale air out across the length of your greenhouse.