Energy performance of residential roofs in Canada-Identification of missing links for future research opportunities

Energy performance of residential roofs (EPRR) is the capability to impede energy flows through a roofing assembly, which may occur as heat loss in winter, heat gain in summer, and loss of conditioned air in both seasons. The roof's energy performance is essential to net-zero-energy homes in Canada. However, measures to increase the EPRR should not jeopardize the structural integrity of the roofing assembly nor lead to unhealthy conditions within the building and its envelope due to unwanted side effects. The development of building codes to ensure EPRR thus requires a holistic approach to assure that residential buildings are energy efficient, moisture safe, and durable. This review systematically documents the state of the art on the topic of EPRR for Canadian buildings. Air tightness, attic ventilation, and insulation requirement are the three factors that mainly influence the EPRR. This review contributes in three ways: 1. Existing code specifications from the applicable North American building and energy codes are scrutinized for the above three factors. 2. Extraction of existing knowledge is expanded via a review of North American standards, guidelines, and association practice manuals. 3. Tabulation of the experimental studies carried out in cold climate countries on these three key factors. With this systematic approach, the missing links are identified for the long-term or future research opportunities in each of the three key factors. For the immediate implementation, with this holistic approach, a list of code change recommendations is drafted for possible inclusion in the Canadian building and energy codes. (c) 2021 Published by Elsevier B.V.

Automated summary

The energy performance of residential roofs is crucial for net-zero-energy homes in Canada, but measures to increase it must consider factors such as structural integrity and building health. Air tightness, attic ventilation, and insulation requirements are the main factors influencing energy performance.