As ventilation is vital to climate control in the greenhouse, these handy Automatic Roof Vent Openers are an accessory that will make your life so much easier!! Your roof vents will open automatically when temperatures increase and they will close when the temperatures fall. Automatically! This vent opener has a unique thermally powered piston. The wax material inside the piston increases when heated and pushes the vent open. When it cools down, the vent closes automatically.
One VENT OPENER is needed for each roof vent in order to operate the vent automatically.