80 percent of energy savings from utility demand side management initiatives have stemmed from investments to upgrade existing buildings (CEC 2005). Approximately two thirds of the developed world’s existing building stock is expected to be standing in 2050, further suggesting that maximizing energy efficiency relies in large part on implementing efficiency upgrades to today’s existing building stock (ürge-Vorsatz et al. 2007). The energy savings potential of the residential sector is particularly large. According to estimates by Granade et al. (2009), cost effective upgrades to building shell, major appliances and lighting in existing buildings could realize a 23 percent reduction in end-use energy from existing residential buildings between now and 2020, and a 22 percent reduction in GHG emissions. Moreover, Granade et al.’s analysis indicates that the potential economical energy savings from the existing residential sector are greater than those available in existing commercial buildings. Thus, savings in the residential sector are especially important to realizing the full benefits of energy efficiency. Such benefits are outlined below. 1.2.1 Environmental and Health Benefits Maximizing building energy efficiency will be critical to mitigating climate change and other environmental challenges in the coming decades. By one estimate, cost-effective building efficiency improvements represent 13 percent of all greenhouse gas emissions reduction potential globally (McKinsey & Company 2009). Maximizing this emissions reduction potential is especially urgent given that the prospects for limiting dangerous climate change are increasingly becoming limited (Anderson and Bows 2011).2 Further supporting the case for energy use reductions, recent studies have suggested that common energy sources such as conventional natural gas, shale gas, and coal, may be more greenhouse intensive than assumed by current emissions accounting standards (Howarth, Santoro, and Ingraffea in press; Tollefson 2012; Shindell et al. 2012). In addition to mitigating climate change, efficiency lessens other environmental impacts of energy extraction, distribution, and use. Such impacts include air pollution, water pollution, and landscape degradation. With proper attention to healthy and green building practices, energy upgrades also serve to improve indoor environmental conditions, such as temperature and air quality. This improvement may reduce occupants’ morbidity and mortality amongst lower income households, and increase occupants comfort and productivity (Clinch and Healy 2000; Kuholski 2010). Conversely, it is important that upgrades be performed by suitably knowledgeable contractors, to avoid exacerbating indoor environmental health problems and/or structural issues, by overly restricting air flow, engendering moisture problems, and/or increasing exposure to contaminants like lead paint (Bone et al. 2010; Manuel 2011). 1.2.2 Economic Benefits Energy efficiency can realize local and regional economic development benefits by creating jobs, retaining energy spending in local circulation, and stimulating greater spending in local economies. 2
Global greenhouse gas emissions are increasing at rates higher than projected in the most pessimistic scenarios of the International Panel on Climate Change (IPCC); moreover, recent research suggests that even modest global average temperature increases will be more dangerous than IPCC assessments have thus far indicated (Anderson and Bows 2011).
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