The article describes from an architectonical point of view the design, assembly, and energy behavior of a prototype for air-conditioning in residential buildings using Peltier cells, which means the application in the field of construction of a technology used in very specific areas. The new system has been designed as an independent, prefabricated, modular construction element that must fit perfectly between the structural floors and is easily adapted to the demands of different buildings. The thermoelectric cooling heating unit is designed to offer a high level of comfort to those living in the building. The only mechanical elements are the dissipation heat fans placed on the outside of the prototype, and heat sinks to transfer the heat from the power elements, reducing the possibilities of failure. The result of all these ideas is the construction of a prefabricated module, consisting of a simplified inhabited housing unit with a thermoelectric installation serving the module, which has obtained a national patent. The results of the thermal and electric behavior demonstrate that the system does not work as well as had been expected; nevertheless, the system has a high potential for its use in buildings associated with photovoltaic.