State of the Art Methodology to Assess Energy Facade Retrofits (EFR)

This paper summarizes findings from existing literature and proposes a methodology to assess facade retrofits. Literature review indicates that research on energy-based retrofits isolates limited factors and does not address the holistic benefits associated with facade retrofits. Many cases of energy upgrades in practice that included facade retrofit describe energy savings, but without any quantification of the facade contribution to those savings. In addition, current practice considers the facade as a last step in the process of energy upgrades, confined to being part of a ‘deep’ or ‘comprehensive’ intervention. This is primarily due to the higher initial costs of facade replacement or renovation. An extended understanding of facade retrofit from the perspective of related fields would help to establish a more comprehensive evaluation of its benefits. A proposed methodology to perform life cycleassessment of facade retrofits that are initiated with an energy-based systems retrofit is described in this paper. It recognizes the building skin as the key system in the total building performance. Total performance refers to energy, human and financial parameters. The different perspectives considered in the methodology include Building Science, Human Comfort, and Real Estate fields. Building Science is used to evaluate several energy retrofit alternatives and resulting energy reductions are obtained from energy simulations. A sensitivity analysis assists in evaluating and selecting the most beneficial input facade parameters. Human Comfort responses to environmental factors influenced by the facade are analyzed from existing literature and findings are used as reference. Real estate gains and losses are evaluated based on current market trends to appreciate the influence of facade improvements. A holistic methodology to evaluate overall building performance enhancements of facade retrofit could provide a paradigm shift in the importance of facade retrofit on our existing building stock.