Under a project funded by the Republic of Korea through the Seoul Initiative Network on Green Growth at the request of the MET, a United Nations Economic and Social Commission for Asia and the Pacific (ESCAP) Project technical team visited HOBs and heating users in Ulaanbaatar (UB) and Darkhan in 2023 to measure the heat supply efficiency. Thirteen technical considerations for improving HOBs were identified in five areas: i) Energy transition, ii) Fuel transition to gas HOBs, iii) Improvement of fuel supply, iv) Improvement of coal-fired HOBs, and v) Improvement of heat transmission and use. The Project Technical Team found that coal-fired HOBs operate with a low combustion efficiency of around 50% or less, resulting in excessive coal use.