The Automatic Vent Opener was made to automatically control the temperature and humidity levels and offer additional ventilation when needed, making gardening easier. As the surroundings in the greenhouse warms, the vent gradually opens to enable the correct amount of air flow in to the greenhouse and closes when the temperature cools. The vent arm was made with a metal cylinder that contains wax which expands when heated to push a piston, which raises the home window, as the air gets warmer, then contracts since it cools, closing with the utilization of a springtime and resetting the piston. All you have to to do is certainly to install it on your own roof vent 
screen and it immediately starts functioning. The Automatic Vent Opener functions without the use of electricity and is compatible with all Palram greenhouse Automatic Greenhouse Vent models only. The solar driven Vent Opener will begin to open as temperature ranges inside your greenhouse reach 68 degrees F with full-open at 80 degrees. It installs efficiently and will provide care-free ventilation.
Ingenious temperature-sensitive device that automatically opens and closes coldframe lids, greenhouse windows and even skylights. Works during the day and maintain a continuous interior climate, something impossible to accomplish by manual adjustments.
Requires simply no batteries or electricity.
It could be adjusted to start opening between 60-77°F. Fully open up at 86-90°F. Fully closed at 55°F.
Strongly recommended for most our glazed season extenders since it dramatically improves plant growth.
The hydraulic cylinder includes a 1 year warranty. The common duration of the cylinder is usually 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 home window or vent weighing as much as 32 lb. For larger panes use the more powerful Gigavent with all metal building, to lift up to 65 lbs.