THE INFLUENCE OF PASSIVE MEASURES ON BUILDING ENERGY DEMANDS FOR SPACE HEATING AND COOLING IN MULTI-UNIT RESIDENTIAL BUILDINGS Aylin Ozkan 1 , Ted Kesik 2 and William O'Brien 3 1 Ph.D. Candidate, Istanbul Technical University, 2 Professor, University of Toronto, 3 Assistant Professor, Carleton University ABSTRACT This paper explores the development of a methodology to assess the relative impact of passive measures on building system performance. Over the life cycle of a building, its use and occupancy can undergo significant changes when the building is re-purposed. Initial energy modeling assumptions about active systems that respond to occupancy and operating schedules may no longer apply. The most persistent attributes are the passive features of the building such as the building form and solar orientation, the overall effective U-value of the enclosure, fenestration and fixed shading devices, and its thermal mass and airtightness. Parametric simulations of the energy performance of multi-unit residential buildings form the basis of this paper and results are ranked to indicate the relative significance of various passive features to the peak and annual energy demands for space heating and cooling. INTRODUCTION It is widely acknowledged that architects and building designers seldom use building performance simulation tools at the early design stage to inform their schematic building designs [1]. Despite the numerous research efforts devoted to advancing early stage design and the significant promise held by the approaches advocated, most architects prefer formulaic versus parametric approaches to building design. Another trend in building design is the use of rating systems to guide the designer to achieve the maximum rating for the minimum expenditure. This often leads to a situation referred to as 'high cholesterol buildings' where sophisticated HVAC, lighting and control systems compensate for underperforming building envelopes [2]. In view of this reality, and in recognition of the primacy of passive systems in the environmental performance of buildings, this paper is based on the development of a methodology aimed at providing robust default values for passive system parameters for a given building typology in a particular climatic location. The objective is to determine passive attributes, such as overall effective U-value, that are at or near the point of diminishing returns in terms of physical, rather than economic, performance. METHODOLOGY The methodology underlying this paper is derived from a larger study aimed at improving the resilience and thermal comfort of new condominium buildings in Ontario and British Columbia. Determining the effectiveness of passive strategies to minimize the demand for space heating and cooling energy is part of a more holistic and comprehensive methodology aimed at developing recommendations for best design practices, as depicted in Figure 1. In this paper, only the Toronto, Canada climate will be considered to demonstrate aspects of the methodology. Figure 1. Passive strategies analysis methodology.