Energy-Saving and Ecological Renovation of Existing Urban Buildings in Severe Cold Areas: A Case Study

High-rise buildings in cold regions have a requirement of ecological improvement due to the continuous response to climate change throughout the year. This study evaluates wind environment, light environment, thermal environment, and energy consumption environment using Phoenics, Ecotect, and DesignBuilder tools, utilizing a high-rise residential building in an intensely cold place as an example. With the goal of repairing the buildings, green energy-saving measures are applied from the perspectives of form, structure, system, and equipment strategy. The energy-saving rates and carbon dioxide emission reduction rates of the renovated buildings were predicted. The results reveal that, in the building performance diagnostic, the wind speed clearly rise at the building’s corner, particularly on the outdoor level and the top floor; meanwhile, the inside lighting is insufficient, and there is a glare hazard adjacent to the window. The performance of the target building has unquestionably increased following the repair of 12 measures, including the bay windows, exterior walls, and solar energy. The influence of strong winds in winter and tranquil winds in summer greatly decreased in terms of the wind environment. In the light environment, indoor lighting is more uniform; the range of (Universal Design index) UDI100–2000 increased from 9.2% to 32.7%; and UDI2000, which may cause glare, decreased by 28.4%. Energy savings and pollution reduction rates were as high as 19.8% and 38.8%, respectively, due to the installation of solar photovoltaic panels. Based on all the measures, the overall energy saving rate of the target building was 63.8%, and the CO 2 emission reduction rate was 90.3%.