A motor driven lifting assembly includes a ladder, a plurality of fastening members removably and pivotally attached to an upper end of the ladder, and a plurality of wheels attached to a lower end of the ladder. A platform supports the air-conditioning unit and is located at an anterior face of the ladder. A mechanism raises and lowers the platform such that the platform is linearly adjustable along an entire longitudinal length of the ladder. The raising and lowering mechanism is anchored in close proximity to the lower portion of the ladder such that the raising and lowering mechanism is easily operable by the user.