The Automatic Vent Opener was made to automatically control the temperature and humidity amounts and provide additional ventilation when needed, making gardening easier. As the atmosphere within the greenhouse warms, the vent gradually opens to allow the right amount of air flow in to the greenhouse and closes when the temperature cools. The vent arm was made with a steel cylinder that contains wax which Greenhouse Vent Opener expands when heated to force a piston, which raises the window, as the air flow gets warmer, then contracts since it cools, closing with the use of a spring and resetting the piston. All you need to do is to install it on your own roof vent screen and it instantly starts functioning. The Automatic Vent Opener operates without the usage of electricity and is compatible with all Palram greenhouse versions only. The solar run Vent Opener will begin to open as temps 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-sensitive device that automatically opens and closes coldframe lids, greenhouse windows and also skylights. Works throughout the day and maintain a constant interior climate, something not possible to accomplish by manual adjustments.
Requires simply no batteries or electricity.
It can be adjusted to start opening between 60-77°F. Fully open up 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 includes a 1 year warranty. The average lifetime of the cylinder is usually 5-10 years, even though some can last up to 20 years.
Screw directly into polycarbonate panels, wooden, or metal frames. 
The Standard Vent Opener can open up a hinged screen or vent weighing just as much as 32 lb. For larger panes use the more powerful Gigavent with all metal structure, to lift up to 65 lbs.