A vent valve assembly comprising: a housing including an assembly opening formed thereon, the housing defining an interior therein that is substantially evacuated; and a vent valve coupled to the housing the vent valve including: a valve housing including an inner surface, an outer surface, and a valve housing opening extending therebetween, the inner surface defining a valve housing cavity, the valve housing opening disposed over the assembly opening and in fluid communication with the valve housing cavity when a valve element is in an open position; wherein said valve element is disposed at least partially within the valve housing cavity and over the valve housing opening, the valve element being movable between a closed position, in which fluid is prevented from flowing through the valve housing opening into the housing interior, and said open position, in which fluid may flow through the valve housing opening into the housing interior; and bellows coupled to the valve housing and to the valve element, the bellows having an internal chamber and configured to selectively move the valve element between the closed and open position in response to a differential pressure between the bellows internal chamber and the valve housing cavity. a housing including an assembly opening formed thereon, the housing defining an interior therein that is substantially evacuated; and a vent valve coupled to the housing the vent valve including: a valve housing including an inner surface, an outer surface, and a valve housing opening extending therebetween, the inner surface defining a valve housing cavity, the valve housing opening disposed over the assembly opening and in fluid communication with the valve housing cavity when a valve element is in an open position; wherein said valve element is disposed at least partially within the valve housing cavity and over the valve housing opening, the valve element being movable between a closed position, in which fluid is prevented from flowing through the valve housing opening into the housing interior, and said open position, in which fluid may flow through the valve housing opening into the housing interior; and bellows coupled to the valve housing and to the valve element, the bellows having an internal chamber and configured to selectively move the valve element between the closed and open position in response to a differential pressure between the bellows internal chamber and the valve housing cavity. a valve housing including an inner surface, an outer surface, and a valve housing opening extending therebetween, the inner surface defining a valve housing cavity, the valve housing opening disposed over the assembly opening and in fluid communication with the valve housing cavity when a valve element is in an open position; wherein said valve element is disposed at least partially within the valve housing cavity and over the valve housing opening, the valve element being movable between a closed position, in which fluid is prevented from flowing through the valve housing opening into the housing interior, and said open position, in which fluid may flow through the valve housing opening into the housing interior; and bellows coupled to the valve housing and to the valve element, the bellows having an internal chamber and configured to selectively move the valve element between the closed and open position in response to a differential pressure between the bellows internal chamber and the valve housing cavity.