The selection of the researches, to be analysed in this state of art, based on the following factors, Ref. to Table D in figure (16):
- Researches that have applied or proposed criteria to improve thermal comfort or energy efficiency or both of them in the historic residential buildings (houses) in Mediterranean and hot arid zones.
- Researches that have used the environmental concept that is embedded in the historic residential building to improve the contemporary architecture.
- Researches that have dealt with the above-mentioned issues but they have specially studied Ottoman houses in different regions.
The reason behind analysing researches and case studies that are located in hot arid and Mediterranean zones, is distribution of Ottoman houses. Hence, Ottoman empire were located mainly in Turkey, North Africa (Egypt, Algeria, etc.), and Balkan countries.