Soil is among the cheapest and most available materials found in the human living environment. Seeking refuge in the heart of earth and benefitting from soil’s thermal property, based on experience, is a strategy employed in the past across some regions. Also the passive systems are amongst the cheapest methods of providing heating and cooling demands of the buildings. These systems experience the lowest impact of environmental degradation while increasing the energy efficiency of the building through decreasing heat gain and loss. The idea of the earth-sheltered buildings is amongst the passive construction that has been embraced by the architects. An earth-sheltered building, as a passive idea, can guarantee, extensively, the reduction of energy consumption and provides the required conditions for thermal comfort. The present study discusses and investigates the thermal performance of earth-sheltered residential buildings in Yazd city of Iran. To predict this type of constructional thermal behavior, subsequent to field and library studies, thermal simulation was employed using Energy Plus software. Energy Plus software is able to simulate the envelopes adjacent to soil. The simulation process is conducted through depth changing of the soil surrounding the sample, assuming its thermal properties are constant. Considering to the results, by increasing the depth of sheltering in amount of soil, its energy consumption saving will increase. In this situation annual temperature fluctuation decreases 50% and it saves about 67% of energy consumption. In addition the most hours set on thermal comfort zone. This subject adds 50 more days to annual Earth-Sheltered acceptable thermal comfort conditions. Moreover due to investigating of the building orientation as an effective element for energy consumption, south orientation is specified as the best position for energy reduction in Earth-Sheltered.
