We were entrusted with the conversion of a series of very different buildings into micro-dwellings. From the outset, the basic problem emerged: How can we create living conditions consistently of high standards in small apartments in different existing shells? Inspired by train and yacht cabins, we created three "living units" - one sleeping, one of food and one of hygiene. These units are combined with each other in different ways, adapting to apartments of different geometry of different existing buildings. They are designed to offer conditions of comfort, functionality, hygiene and warmth. Their surfaces are simple and smooth, without protrusions, for easy cleaning and frictionless movement around them. Mechanisms and equipment are carefully selected to make minimal noise, withstand, work well, and save energy and water. The three units and their various functions and connections to the building are designed to work harmoniously with each other. The three units make up the Essential Living Unit (ELU), a micro-housing standardization system. The aim is, based on user feedback and design research, to improve the ELU in every version, creating an ever-increasing quality of life for the respective occupants. The first pilot building where the ELU micro-residential standardization system was implemented is located in Kallithea, Attica.