Abstract: A fan coil unit comprising an air conditioning coil using a main cooling coil surrounding by a heat pipe. The cooling coil is face-split to form a first portion for conditioning inside air, as needed, and second portion for continuously conditioning outside air. The air conditioning coil is positioned between an pre-cooler or evaporator coil and a re-heater or condenser coil. The pre-cooler and re-heater are comprised of a plurality of passive heat pipes, at least one circuit for each of the first and second portions of the face-split cooling coil. Each of the circuits is a continuous length of pipe folded into a C-shape having a crossover end and a hair pin end. In this way, vapor can rise in the upper portion of the pre-cooler side, through the upper crossover pipe, to the re-heater side.