Hospitals are human friendly buildings, as they offer recovery, hope and life. However, they have the highest rates of energy consumption, resulting in gases that negatively affect human health. Therefore, hospital buildings should be environmentally friendly buildings. They are not only built to preserving human health, but also to preserve the environment and natural resources. This is done by taking into consideration some of the design standards of hospital buildings and applying some of the green architecture standards in the treatments of external envelope. Such envelop may reduce the thermal load and avoid using mechanical equipment to create the thermal comfort inside spaces. This means increasing the energy efficiency in buildings. To this end a simulation program was used to evaluate thermal behavior, calculate the monthly and annual energy consumption, and calculate the energy saving ratio after using the architectural treatments added to the exterior of the building. The results of the study show that the percentage of energy saving in hospital buildings can reach 49%. The study also developed an analytical approach to evaluate the thermal behavior of hospital buildings in Egypt, which contributes to achieving environmentally sound construction and benefiting the national economy.