The Automatic Vent Opener was made to automatically control the temperature and humidity levels and provide additional ventilation when needed, making gardening easier. As the atmosphere 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 designed with a steel cylinder that contains wax which expands when heated to push a piston, which raises the windowpane, as the air gets warmer, then contracts since it cools, closing with the use of a springtime and resetting the piston. All you need to do can be to install it on your own roof vent window and it instantly starts working. The Automatic Vent Opener functions without the use of electricity and is compatible with all Palram greenhouse 
models only. The solar run Vent Opener will start to open as temperature ranges within 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-delicate device that automatically opens and closes coldframe lids, greenhouse windows and also skylights. Works during the day and maintain a continuous interior climate, something impossible to achieve by manual adjustments.
Requires no batteries or electricity.
It can be adjusted to start opening between 60-77°F. Fully open at 86-90°F. Fully closed at 55°F.
Strongly recommended for all our glazed season extenders because it dramatically boosts plant growth.
The hydraulic cylinder comes with a 1 year warranty. The average duration of the cylinder is certainly 5-10 years, even though some can last up to twenty 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 larger panes use the more powerful Gigavent with all metal Automatic Greenhouse Vent building, to lift up to 65 lbs.