The Automatic Vent Opener was Automatic Greenhouse Vent designed to automatically control the temperature and humidity levels and provide additional ventilation when needed, making gardening easier. As the 
air within the greenhouse warms, the vent gradually opens to allow the right amount of ventilation into the greenhouse and closes when the temperature cools. The vent arm was designed with a metallic cylinder that contains wax which expands when heated to push a piston, which raises the screen, as the atmosphere gets warmer, then agreements as it cools, closing with the use of a springtime and resetting the piston. All you have to to do can be to install it on your roof vent window and it automatically starts working. The Automatic Vent Opener operates without the use of electricity and is compatible with all Palram greenhouse models only. The solar run Vent Opener will start to open as temperatures inside your greenhouse reach 68 degrees F with full-open at 80 degrees. It installs quickly and easily and will provide care-free ventilation.
Ingenious temperature-sensitive device that automatically opens and closes coldframe lids, greenhouse windows and actually skylights. Works throughout the day and maintain a continuous interior climate, something extremely hard to achieve by manual adjustments.
Requires simply no batteries or electricity.
It could be adjusted to begin opening between 60-77°F. Fully open up at 86-90°F. Fully closed at 55°F.
Strongly recommended for almost all our glazed season extenders since it dramatically improves plant growth.
The hydraulic cylinder has a 1 year warranty. The average lifetime of the cylinder is definitely 5-10 years, even though some can last up to 20 years.
Screw directly into polycarbonate panels, wood, or metal frames. The Standard Vent Opener can open up a hinged windowpane or vent weighing as much as 32 lb. For bigger panes use the stronger Gigavent with all metal structure, to lift up to 65 lbs.