Louver windows help the ventilation of a greenhouse.  Adding an Alton Automatic Louver Opener will help regulate the airflow automatically when temperature changes. Automatic attachment for a Louvre vent, fits most louvres.  Its fully adjustable to open over a range of temperatures between 59-77 degrees F. 

Some drilling is required to fit.

Please note that an auto louvre CANNOT fit a louver which is directly left of an a-frame when you look at it internally without extra packing.