In recent years, China's economy has developed rapidly. With the development of society and the process of urbanization, building consumption has increased year by year. In my country, the promotion and implementation of building energy conservation started late, and building energy consumption has increased year by year. Developing building energy conservation and vigorously promoting energy conservation and emission reduction are inevitable choices to promote sustainable development. Among urban residences in the northwest region, high-energy-consuming buildings account for a large proportion, and old residences account for more than 30%. Old residential areas have huge potential for energy conservation and emission reduction. Based on this problem, this paper takes an energy-saving residential project in Northwest China as the research object. This study aims to examine the energy efficiency of building maintenance and structural renovation through data comparison and building energy consumption simulation methods, and aims to provide research ideas for the energy-saving renovation of old houses in severe cold areas.