This paper reports findings of field research undertaken in collaboration with students and scholars from the Green Architecture Research Center of Xian University of Architecture and Technology. The focus of the project is the potential that exists for exploiting the abundant solar resources of Tibet in the development of modern urban and rural housing types while at the same time honoring the traditional Tibetan house form. In current design and research approaches at the GARC, the design of environmentally responsive vernacular building focuses on interventions that increase solar heat collection and circulation of heat throughout the dwelling space. These interventions primarily engage the structure of the dwelling and in the case of the yaodong cave dwellings, also may include the addition of a second floor to increase living space. The interventions alter the original ambiance and daylighting levels of the traditional single cavernous vaulted interior. The GARC interventions are consistent with an MIT study of passive solar interventions on different housing types in Beijing. All post-occupancy evaluations focus on comparative measures of fuel consumption after passive solar gain and air circulation is improved. What we see as missing from these studies is an evaluation of the impact these types of intervention have on the use of interior space. For example, the quality of life as affected by daylight levels within the spaces and on traditional routines and objects of daily living, the material culture as it has been passed down from generation to generation. Through light level analysis, both qualitative and quantitative, we provide insight to the way daylight levels affect current interior living conditions in Tibet. This data is used to test potential design interventions and predict impact on interior light quality with the goal of suggesting that both holistic and culturally responsive design solutions can result