A facility-based dual-purpose conditioned air blower system includes a heat exchange unit, a diverter apparatus, and a centrifugal blower. The heat exchange unit includes an ambient air inlet, heat exchange elements, and a conditioned air outlet. The diverter apparatus includes a diverter inlet fluidly coupled to the conditioned air outlet of the heat exchange unit, a first diverter outlet to the facility, and a second diverter outlet. The diverter apparatus is moveable between a first position wherein the first diverter outlet is closed and the second diverter outlet is open, and a second position wherein the first diverter outlet is open and the second diverter outlet is closed. The centrifugal blower includes a blower inlet fluidly coupled to the second diverter outlet of the diverter apparatus, and a blower outlet positioned to ventilate a trailer interior with conditioned air from the conditioned air outlet of the heat exchange unit.