A spring drive system includes a housing and an extendable window cover that is coupled to the housing. The window cover has at least one lift cord that is employed to retract the window cover. The system also includes a first cord spool and a spring drive system having at least one spring having a storage end that is operably coupled to a storage spool and an output end that is operably coupled to an output spool. The lift cord extends from the first cord spool to the window cover, and the spring drive system has an output that controls tension on the first cord spool and no external hand-operated control cord as an input used to raise and lower the window cover.