Exterior Retrofitting Systems for Energy Conservation and Efficiency in Cold Climates: A Systematic Review

In the United States, approximately 65% of buildings were constructed before 1992, when the United States Department of Energy (DOE) established the Building Energy Codes Program (BECP). Building retrofit to meet and exceed present high efficiency building standards is a critical path to reduce the overall existing building energy consumption and associated carbon emissions. Despite the well-established advantages of building energy retrofit, its adoption has faced numerous challenges. Therefore, it is important to review how effective building energy retrofit approaches can be in specific climatic contexts. This paper aims to provide a systematic and critical review of various exterior retrofitting systems for energy conservation and efficiency in cold climatic conditions, to summarize findings and knowledge gaps, and to identify values and challenges in advancing building envelope retrofits. To this aim, a set of various exterior retrofitting representative techniques was collected from various projects around the world. A summary description of key design elements, thermal performance, airtightness, and improvement areas for each system is presented and discussed. The potential and limitations of each retrofitting approach are evaluated to aid further development of sustainable retrofitting systems. Concluding remarks also converge on the identification of remaining research questions to discuss various issues related to system performance, and to address future opportunities.