Creating comfortable indoor living environment is one of the main aims of designing buildings. To design sustainable and energy-efficient buildings the indoor comfort conditions should be adopted judiciously which may be different for naturally ventilated buildings and air-conditioned buildings and may be related to the outdoor climatic conditions of the location. Although India is divided into five major climatic zones as per the National Building Code of India, uniform comfort standards have been mentioned for all of them. Hence, there is a need to conduct thermal comfort field studies in different climatic regions of India. This study presents the findings from the field-experimentation of naturally ventilated residential buildings at Mandi town in India, having composite climate. The study shows that there is a need to improve the indoor thermal comfort condition of present day houses. The study recommends the need for conducting more such thermal comfort field-survey in different climatic zones of India to develop adaptive thermal comfort standards suitable for that geo-climatic location. Literature review of existing thermal comfort standards is also discussed in this book.