Measurement of Indoor Thermal Environment and Analysis of Heating Energy Saving in Residential Buildings in Ulaanbaatar, Mongolia

Owing to the unique climate of Mongolia, the heat supply of residential buildings is a pressing social and economic problem. In Mongolia, the heat loss indicators for numerous residential buildings still exceed the standard. There is an urgent need to update and improve the architectural structure of residential buildings for energy saving. Few studies focused on energy consumption and the indoor environment in residential buildings in Mongolia. To provide effective and practical energy-saving measures, we conducted field surveys and measurements to clarify the energy consumption and indoor environment in residential buildings. A questionnaire was used to collect data from 100 households in Ulaanbaatar (the capital city of Mongolia), and five representative buildings were selected as the study objects to investigate the indoor thermal environment. The measurement result shows that the average indoor air temperature and relative humidity in the living rooms and bedrooms were 25.4 °C and 26.3%, 24.0 °C and 33.2%, respectively. The indoor air temperature was higher, and the air humidity was lower than the national standards. The average ventilation rate lies between a maximum of 71 m 3 /h and a minimum of 46 m 3 /h. The breakdown of the total heat loss shows that the ventilation heat loss of two objects is high. The total heat loss for the study objects was between 1.202–1.694 W/(m 2 K). The analysis result reveals that there exist great potential and effective measures to save heating energy.