A fastener driving apparatus includes a drive mechanism, a drive piston disposed with in a cylinder and operatively coupled to the drive mechanism, and an anvil coupled to the drive piston. The apparatus also preferably comprises a biasing element for temporarily holding the drive piston at BDC of the piston cylinder. The drive mechanism is capable of selectively applying force on the drive piston to move the drive piston away from BDC of the piston cylinder. When the drive mechanism engages the drive piston to move the drive piston away from BDC, a vacuum is generated in the cylinder, which vacuum, after the drive mechanism disengages the drive piston, acts on the drive piston to cause the piston to move toward BDC and the anvil to drive a fastener. A sealed air chamber on the side of the piston opposite the vacuum may assist in generating force.