Abstract: Apparatus and methods provide for a dual pass air flow configuration in an air conditioning system to improve efficiency and performance of the air conditioning system. An air conditioning device includes a pre-conditioned air passage chamber separated from a post-conditioned air passage chamber by an impermeable partition. A coil system separates the pre-conditioned air passage chamber and the post-conditioned air passage chamber from a partially-conditioned air passage chamber. The coil system is configured to receive air from the pre-conditioned air passage chamber and to condition the air passing through the coil system into the partially-conditioned air passage chamber. The coil system is also configured to receive the air from the partially-conditioned air and further condition the air as it passes through the coil system into the post-conditioned air passage chamber.