1. Descriptive  section
This section  includes three parts as the following:
A.     Analysing climate conditions in  Cairo, Egypt. The Weather data of Cairo is extracted from weather station in  Cairo number (623660-HECA) which is located in Cairo airport and Weather file  (IWEC) using Best Energy software.
B.      Thermal comfort requirements  for existing residential buildings in Cairo.
C.      Description of Historic houses  in historic Cairo. 
2. Analytical  section of the case study
In this section,  the concept of “transdisciplinary approach” will be used. This section includes  four steps as the following:
A.     Simulation of thermal comfort level  
B.      Calibration
C.      Assessment of Retrofit Actions
D.     Comparison and discussion
A. Simulation of thermal comfort level
Best Energy, which is an interface for  Energy plus, will be used as a tool in order to quantify the following items;
- The impact of building layout  and orientation on the thermal comfort of the indoor spaces.
- The impact of shading from the  neighbours and solar heat gain of the external surfaces   
- Thermal behaviour (Ex: thermal  transmittance) on the building envelop (Walls, Roof, Windows).
B. Calibration  
The result of the simulation software will  be calibrated and compared with national and international references in order  to understand the needs of adjustment to achieve the thermal comfort  requirements, and suggest the retrofit options.
These references are:
1. ASHRAE: Guideline-34P, “energy guideline  for historical buildings and structures”, and ASHRAE-55 for the thermal comfort  requirements, ASHRAE 14 will be used.
2. Egyptian code of Energy Efficiency for residential buildings: This code is the only one code  in the energy efficiency of the buildings in Egypt. It includes the new buildings  and the existing one and it focus on the houses. However, there is no  explaining about the historical buildings.
The aim of comparing the  simulation result with this code is to test the possibility for applying this  code in the field of the cultural heritage in Egypt.
The result of this step is summarized in this table H in figure (26), also refer to Appendix 3: