A self-contained air conditioner unit incorporates an energy recovery ventilator portion that brings about several changes of room air per hour with outdoor fresh air. There is an outdoor air intake plenum which furnishes the fresh air and the condenser air for the condenser coil, and a return air plenum. Air from the room return air plenum is HEPA filtered and conducted to the evaporator coil and evaporator fan, and is supplied back into the conditioned space. The energy recovery ventilator has a counterflow heat exchanger core situated between the return air plenum and the fresh air intake plenum, as well as two ventilation fans, one (or both) of which may be of variable or multiple speed. By controlling the fan speeds, it is possible to produce a neutral pressure, a positive or overpressure, or a negative or underpressure in the conditioned space. The unit can be wheeled into place and installed easily by personnel without special training. The unit can be scaled up in size and capacity for a larger room or whole house applications, or scaled down for smaller rooms or window mounting.