The article demonstrates that the Ger Plug-In, a housing prototype that combines the traditional Mongolian nomadic dwelling, or ger, with new construction, is a viable sustainable and affordable housing product that addresses urgent issues that have arisen from the growth of Ulaanbaatar’s ger districts. These settlements have no water supply, sewers or centralised heating, and households use coal and coke briquettes to heat their homes. The prototype provides the ger with electrical heating,, sanitation systems and improved thermal insulation. The pilot project was constructed in 2017 and on-site field measurements together with numerical simulation have been used to calculate its Energy Use Intensity (EUI). By using both quantitative and qualitative methods, the results show that the Ger Plug-In meets the EUI criteria to be eligible for green mortgages provided by the Green Climate Fund. Household surveys were conducted to ascertain the financial capacity of residents. By proving its qualification for low interest rate mortgages and by evidencing its market demand, the objective is to demonstrate that the product can have scalable impact for the 840,000residents living in the ger districts.