A height-adjustable, concealed heating and cooling system that includes a heating and cooling unit and an adjustable frame that enables the (vertical) position of the heating and cooling unit to be modified and to be attached to framing members of a wall or another heating and cooling unit. The heating and cooling unit also includes a housing that is attached to the frame. The housing extends into the wall to define a recess portion through which a heat and/or cooling supply pipe with heat-dissipating fins attached thereto extends.