The Automatic Vent Opener was made to automatically control the temperature and humidity amounts and Automatic Greenhouse Vent provide additional ventilation when needed, making gardening easier. As the air flow inside the greenhouse warms, the vent gradually opens to allow the right amount of air flow into the greenhouse and closes when the temperature cools. The vent arm was designed with a metal cylinder containing wax which expands when heated to drive a piston, which raises the home window, as the surroundings gets warmer, then contracts since it cools, closing with the use of a springtime and resetting the piston. All you need to do is usually to install it on your roof vent window and it instantly starts functioning. 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 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 also skylights. Works during the day and maintain a constant interior climate, something not possible to attain by manual adjustments.
Requires no batteries or electricity.
It can be adjusted to begin 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 increases plant growth.
The hydraulic cylinder comes with a 1 year warranty. The average duration of the cylinder is usually 5-10 years, even though some can last up to twenty years.
Screw directly into polycarbonate panels, wood, or metal frames. THE TYPICAL Vent Opener can open up a hinged windows or vent weighing just as much as 32 lb. For larger panes use the stronger Gigavent with all metallic structure, to lift up to 65 lbs.