Chapter 38 Passive Cooling of the Traditional Houses of Nepal Hom Bahadur Rijal Abstract For the purpose of evaluating passive cooling effects in summer, a thermal investigation of traditional houses was conducted in the sub-tropical region of Nepal. The results were as follows: (1) daytime indoor air temperature is 4.6 K less than outdoor air temperature. (2) The daytime surface temperature of the thatched roof is lower than the clay tile and cement tile roof. The results indicate that passive cooling and moisture control effects are found in traditional houses with earthen floors, thatched roof, mud and brick walls and mud vessels which are effective in producing thermal comfort for residents. Keywords Nepal · Traditional house · Mud vessel · Passive cooling · Thermal environment 38.1 Introduction Sometimes extremely hot climatic conditions necessitate specially in adapted types of housing, which incorporate a variety of passive cooling methods designed to keep indoor environmental conditions thermally comfortable. In the sub-tropical region, traditional houses are designed to exploit building elements such as earthen floors, eaves, huge mud vessels and brick walls to produce high thermal mass. However, in these same structures, defects can be found. Large gaps in doors and between the top of walls and the roof severely detract from the overall cooling effect, instead creating excessive heat. Firewood combustion in kitchens also contributes to high indoor air temperatures. In addition, the gradual increase in the use of cement roofs further intensifies indoor heat. There is no known, substantial research on thermal mitigation in traditional Nepalese houses. However, such research is imperative if this low-energy consumption lifestyle is H. B. Rijal (*) Department of Restoration Ecology and Built Environment, Tokyo City University, 3-3-1 Ushikubo-nishi, Tsuzuki-ku, Yokohama, 224-8551 Japan e-mail: rijal@tcu.ac.jp © Springer Nature Singapore Pte Ltd. 2018 T. Kubota et al. (eds.), Sustainable Houses and Living in the Hot-Humid Climates of Asia, https://doi.org/10.1007/978-981-10-8465-2_38 397