Automatic Louver Window Opener for Palram-Canopia GreenhousesDESCRIPTION The Automatic Louver Vent Opener was designed to automatically control the temperature and provide additional ventilation in all Palram and Rion Greenhouses. As the air inside the greenhouse warms, the vent gradually opens to allow the correct amount of air flow into the greenhouse and closes when the optimal temperature is reached. The vent arm was designed with the use of natural minerals that expand with heat to push a piston, which