Differences Between a Wall & a Window Air Conditioner Unit

Slide-out Chassis

• A wall air conditioner's chassis differs from that of a window unit. The chassis of a wall unit slides out from the case and is usually secured only by a few screws. The chassis rides on a track inside the case that gives the internal components the proper pitch to enable effective draining of condensation and proper operation.

Fixed Chassis

• Window air conditioners contain what is called a fixed chassis and cannot be installed in walls. A fixed chassis is one that does not slide out, with the internal components of a window air conditioner being tied to the air conditioner case itself, which makes securing the air conditioner in a wall hole a precarious and exceedingly dangerous endeavor that should not be attempted.

Support

• Wall units are supported by either a brace on the outside of the wall or by being tied into studs on either side of the opening. Window air conditioners are supported by their own weight pressing down on the window jam and a slight outward pitch that puts pressure on the bottom part of a double-hung window.

Venting

• Window air conditioners typically have a large vent across the back for exchanging heat and fins on the sides of the unit for air circulation. Due to the fact that walls are typically much thicker than windows, wall air conditioners are designed to do all of their venting from the back of the case. Installing a window unit in a wall, even when it is properly supported, can lead to overheating due to ventilation fins being blocked by the wall.