ABSTRACT: Existing buildings consume 40 percent of the primary energy in the US. While new zero-energy buildings can gradually reduce this energy use, the existing building stock must be improved through deep energy retrofits to make a significant impact in this sector. Current energy retrofits and research in the US focus primarily on upgrades of mechanical and lighting systems to maximize energy reduction for minimal investment. This incremental approach is effective but limited in the overall energy savings it can generate, as major transformations to the fundamental operation of a building are cost prohibitive. Due to their disruptive nature, structural retrofits offer the physical and economic opportunity to completely transform how a building operates in terms of heating, cooling and lighting – the largest sources of energy use. Consequently, this paper proposes replacing current incremental strategies prevalent in most energy efficiency retrofits with transforming existing buildings through a multi-performance retrofit that (1) improves the structural response to extreme-event loading, (2) maximizes daylight to replace electric lighting, (3) uses low-temperature radiant systems to replace HVAC units, (4) deploys climate-appropriate thermal mass and (5) upgrades the envelope to (6) effectively maximize passive thermal and bioclimatic strategies. This paper documents a database of 25 commercial buildings, primarily from the Pacific Northwest region of the US that have undergone different types of retrofits. Overall, multi-performance retrofits are more expensive than a stand-alone structural or energy retrofits but provide benefits that are not easily quantified. Three multi-performance retrofits are described in more detail to highlight the strategies used and benefits of this approach. KEY WORDS: Multi-performance retrofit; Integrated design, Resilience. 1 INTRODUCTION 1.1 EnvironmentalImpactofBuildings Existing buildings consume 40 percent of the primary energy and contribute 40 percent of CO 2 emissions in the US [1]. These numbers exclude the significant environmental impact of manufacturing, transporting, installing, maintaining and eventually demolishing materials used in building construction [2]. While every other sector has been reducing energy use over the last 30 years, commercial buildings have increased their energy intensity (energy use per square foot) by over 8%. Furthermore, the total square footage of these buildings has increased by almost 60% over the same time period. Only the recent recession temporarily blunted what had been the continual growth in energy use by the building sector [1]. It is well documented that deficiencies in building performance are ubiquitous, and if addressed nationally in the US could contribute to over $18 billion in savings annually [3]. Thus, to mitigate climate change, there should be no higher priority than ensuring that residential and commercial buildings are created, adapted and retrofit to minimize energy use, resource consumption, and cost. While new resilient, zero-energy buildings (ZEBs) can gradually reduce the environmental impact of this sector, the existing building stock must be improved through energy retrofits to make a significant impact. In the US, buildings built before the year 2000 make up 78 percent of the commercial building stock and account for 77 of total building fuel consumption [4]. 1.2 ConventionalEnergyRetrofits Current energy retrofits and research in the US focus primarily on upgrades or commissioning of mechanical and lighting systems to maximize energy reduction for minimal investment [5, 6, 7, 8]. This incremental approach is effective but limited in the overall energy savings it can generate. It should also be noted that the majority of studies in the US use computer modelling instead of monitoring buildings that have undergone energy retrofits. Unfortunately, there is little to no funding in the US to measure the performance of existing buildings to assess the relative merits of deployed retrofit tactics or for researchers to take an active part in the design, construction, commissioning or operations of a recently renovated building. Stakeholder behaviour will not be shifted from current patterns of incremental energy efficiency upgrades unless measured performance data from real buildings is presented to them [9]. Major transformations to the fundamental operation of a building that could reduce energy use intensity (EUI) to levels associated with ZEBs are deemed cost prohibitive and miss the opportunities to “tunnel through the cost barrier” [10]. These major transformations are also inhibited by a desire for buildings to remain operational during an energy retrofit to avoid displacing occupants [11]. Consequently, an analysis by the author of New Building Institute’s “Getting to Fifty” database - which houses details and measured data on buildings that have undergone what NBI calls “deep energy retrofits” that use 50 percent less energy than conventional Multi-performance retrofits to existing buildings: Increasing resiliency and reducing the environmental impact of buildings through simultaneous structural and energy retrofits Corey Griffin 1 1 School of Architecture, Portland State University, PO Box 751, Portland, Oregon, USA email: cgriffin@pdx.edu Civil Engineering Research in Ireland 2016 7