An air-conditioning unit is provided, comprising: an input vent for receiving return air; an intermediate vent; an output vent; a blower fan proximate to the input vent for moving the return air from the input vent to the intermediate vent; and an air-conditioner coil between the intermediate vent and the output vent including an active portion including one or more operational air-conditioning coils that receive a first portion of the return air from the intermediate vent, for circulating a coolant, condition the first portion of the return air by heat exchange with the coolant to create conditioned air, and pass the conditioned air to the output vent, and an inactive portion that does not circulate coolant and passes a second portion of the return air as unconditioned air to the output vent, wherein the conditioned air and the unconditioned air pass through the output vent as supply air.