Abstract: A direct outdoor air system may include an enclosure having an air inlet to direct environmental air into the enclosure, a heat exchanger section to receive the environmental air and direct conditioned air to an air outlet of the enclosure, and a blower section to receive the environmental air from the air inlet and direct the environmental air to the heat exchanger section via an air flow path between the blower section and the heat exchanger section. The air outlet may direct the conditioned air to a conditioned space. The direct outdoor air system may also include a heat exchanger disposed in the heat exchanger section to condition the environmental air, generating the conditioned air, and a blower disposed in the blower section to motivate the environmental air through the air flow path. Additionally, a heat exchange area of the heat exchanger may be oriented vertically relative to gravity.