One of the fundamental parameters for low energy architecture strategies implementations is to allow solar sun penetration into buildings, which can contribute to free heating in buildings and reduce energy consumption during cold season; through many design strategies that could be applied to buildings.
 
 This is not easily achieved until a complete analysis of solar accessibility is done, which in turn enables us to decide whether such strategies are applicable or not.
 
 Amman city is a case where such analysis is a must due to the problems of fuel scarcity and high fuel costs as well. In addition, the topographical nature of Amman city is not plain; rather it is almost mountainous, which makes it important to ensure solar accessibility on slope sites.
 
 Much of modern apartments in Amman were built on sloped sites.
 
 Method of research will depend on selected cases for solar radiation quantification for a number of cases including mainly modern residential buildings built on slope sites; this method will depend mainly on graphical analysis for solar penetration (INSOLATION) and theoretical calculations for the different cases.
 
 Calculations of solar radiation were based on measured global irradiation, they were calculated for the under heated period for Amman; then a strategy were built to derive new set back values.
 
 Recommendations will be as a set of rule of the thumb for direct application for the practicing architect, and they are reflected as new setback values between buildings. It will be the first step towards a complete set of regulations to ensure solar accessibility to buildings constructed on slope sites in Amman city and for other regions of similar slopes, looking for the target of maximizing solar radiation availability for minimizing fossil fuel consumption as an introduction to the study of sustainable buildings in Jordan.