Abstract: This invention discloses a low-noise cross-wall (“saddle” shaped) air conditioner window unit. The unit includes an indoors casing that houses the condenser and compressor and an outdoors casing that houses the evaporator. A connecting frame (which straddles the windowsill) connects the indoors and outdoors casings. In a first embodiment, an axial condenser fan and a centrifugal fan evaporator fan are driven simultaneously by a dual-axle motor housed in the outdoors casing. The axle driving the indoors evaporator fan extends through the connecting frame over the windowsill. In a second embodiment, the evaporator fan is a cross-flow fan. Both features are designed to make the unit lightweight and quiet indoors. The full specification discloses additional novel features such as venting patterns and perforated frames, also for making the unit lightweight, efficient, and/or quiet. Installation is enabled with spacers or fasteners, not requiring support brackets.