Executive SummaryThis analysis was conducted by Pacific Northwest National Laboratory (PNNL) in support of the U.S. Department of Energy's (DOE) Building Energy Codes Program (BECP). DOE supports the development and adoption of energy efficient and cost-effective residential and commercial building energy codes. These codes set the minimum requirements for energy efficient building design and construction and ensure energy savings on a national level. This analysis focuses on one and two family dwellings, townhomes, and low-rise multifamily residential buildings. For these buildings, the basis of the energy codes is the International Energy Conservation Code (IECC). This report does not address commercial and high-rise residential buildings (four or more stories). This technical support document provides additional detail and documents the specific assumptions used in applying the cost-effectiveness methodology. iv The analysis is conducted using DOE's EnergyPlus simulation software. PNNL developed two prototype building models to represent the single-family and the multifamily buildings defined in the methodology. These two prototypes were then expanded to a suite of 32 energy models to represent four commonly used heating systems in homes (i.e., gas furnace, oil furnace, heat pump, and electric furnace) and four commonly used foundations (i.e., vented crawlspace, slab-on-grade, heated basement, and unheated basement). Different versions of the models are created to match the requirements of the 2006, 2009, and 2012 IECC for each location. The entire set is simulated across 119 locations to represent the different climate-zone and moisture regimes in each state across the country. The annual energy consumption for space heating, cooling, domestic hot water heating, and lighting is extracted for each case. The energy use is converted to energy cost using fuel costs in the different states. Incremental first costs are calculated for each location for the energy provisions of the 2009 and 2012 IECC over the baseline code, as applicable, using the Building Component Cost Community (BC3) data repository. 1 These first costs are adjusted for variation in construction and material costs across the country using location multipliers developed by Faithful+Gould for PNNL. 2 The energy costs and first costs are aggregated based on new housing construction starts from the U.S. Census data 3 , weights of the different foundation types from the Residential Energy Consumption Survey data 4 , and heating system weights based on National Association of Home Builders data (NAHB 2009). Life cycle cost (LCC) analysis is then conducted for each case to assess cost effectiveness. DOE uses LCC as the primary measure of cost effectiveness.
The 2009 and International Energy Conservation Codes (IECC) yield positive benefits for U.S. homeowners and significant energy savings for the nation. Moving from a baseline of the 2006 IECC to the 2009 IECC reduces average annual energy costs by 10.8%, while moving from the same baseline to the 2012 IECC reduces them by 32.1%. Highlights National average energy savings against a 2006 IECC baseline: • The 2009 IECC saves 10.8% of energy spent for heating, cooling, water heating, and lighting • The 2012 IECC saves 32.1% Long-term cost-effectiveness for consumers: • Life-cycle cost savings over a 30-year period, averaged across all building types and configurations, are significant in all climate zones
Occupancy Changes 2-4 Remodels 2-4 Relationshipof ChangeFrequency to Building Size and Vintage 2-5
Executive SummaryTheAn overview of the 2009 IECC and its major chapters, as well as a brief comparison to previous versions, is provided as introductory information. The IECC is then briefly compared to the International Residential Code, which contains a chapter with energy efficiency requirements that are very similar to the IECC.Several states have either not adopted a mandatory energy code or developed their own codes which have minimal or no connection to the IECC. The latter-including California, Florida, Oregon, and Washingtonwere not included in this analysis as the codes in these states would be difficult to appropriately compare to the 2009 IECC and most of these states have energy offices that have already assessed the IECC on their own.Chapter 2 is dedicated to outlining some of the major code differences in the 2009 IECC that are not contained in any previous version of the code, and to which much of the energy savings of the 2009 IECC compared to previous versions is attributable. These energy saving differences are described in further detail in the report, and include: Mandatory duct pressure testing coupled with maximum allowable duct leakage rates. These requirements are applicable when any portion of the ducts are outside the conditioned space. A requirement that 50% of lamps in a residence must be energy efficient Several improvements in basic envelope requirements Elimination of trade-off credits for high efficiency heating, cooling, or water heating equipment.The full results of each state specific analysis are provided in the following report.
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