Each country known by its architectural identity, so it is scary when this identity is vanished, destroyed, reused in a bad way, or abandoned with no use. Egypt faces a great problem in reusing Historical buildings in an effective way; it is reused by wrong functions that destroyed it. This paper aims to implement sustainability in our Historical buildings, to cope with our requirements to be healthy buildings, preserving its aesthetic value, as well as being a flag for showing the Egyptian sustainable identity. Regarding to the crisis of covid-19, the paper goal is to apply sustainable retrofit for Historical buildings, using passive solar energy by using the double height ceiling, long windows, and wind capture, to ventilate the building without using AC. The simulation use the design builder as a software, for producing a methodology to implement sustainability in our Historical buildings.