A heating, ventilation and air conditioning system including a casing with a vent outlet, a blower chamber within the casing, a wall cooperating with the casing to form a descending air passage permitting a downward flow of air discharged from the blower chamber and an ascending air passage permitting an upward flow of air passing through the descending air passage toward the vent outlet. A heating heat-exchanger is substantially horizontally disposed within the ascending air passage and arranged adjacent to a recessed portion of the wall and at least partially overlapping in the vertical direction with a cooling heat-exchanger disposed between the blower chamber and the heating heat-exchanger. A bypass air passage bypassing the heating heat-exchanger is substantially linearly aligned with the vent outlet via the ascending air passage. A foot vent passage is disposed above the heating heat-exchanger and between the blower chamber and the ascending air passage.