Benchmark House Specifications
The following sections summarize the definition of the Benchmark, updated for the FY 2010 BA funding agreements. A comprehensive description of other important BA reference houses (Builder Standard Practice and Regional Standard Practice), along with guidance for using hourly simulation tools to compare an energy-efficient Prototype house to the various base-case houses, can be found in the NREL technical report addressing systems-based performance analysis of residential buildings (Hendron et al. 2004). NREL and other BA partners have also developed a series of tools, including spreadsheets with detailed hourly energy usage and load profiles, to help analysts apply the Benchmark quickly and in a consistent manner. These tools can be found on the BA Web site (http://www1.eere.energy.gov/buildings/building_america/ perf_analysis.html). In addition, the Florida Solar Energy Center (FSEC) has developed a version of EnergyGauge that automatically generates the Benchmark model when the specifications for a Prototype house are entered.
Any element of the Benchmark definition that is not specifically addressed in the following sections is assumed to be the same as the Prototype house. Because the definition is intended to be software-neutral, certain elements of the Benchmark cannot be modeled directly using every common simulation tool. If the energy use associated with such elements is significant, then they should be modeled or hand-calculated separately from the building model and reasonable adjustments should be made to the whole-house simulation results. If there is no significant energy effect associated with these elements, the Prototype and Benchmark should be modeled using similar approximations in an energy-neutral manner. The full Building America Performance Analysis Procedures (Hendron et al. 2004) include application notes addressing some practical implementation issues that may be encountered when simulating the Benchmark using DOE-2.2.
The Benchmark may be applied to either a single-family or multi-family home. A single-family home is contained within walls that go from the basement or the ground floor (if there is no basement) to the roof. A single-family attached home is defined as a single-family home with one or more stories that shares one or more walls with another unit. The single-family attached home definition includes, but is not limited to, duplexes, row houses, and townhomes.
A multi-family home (or multi-family building) is defined as a building with at least five housing units. Each multi-family housing unit must share at least a floor or a ceiling with another unit. Also, there may be no more than three stories for a given multi-family building, otherwise it is considered a commercial building, which is outside the scope of this document. These definitions are consistent with those provided by the RECS database (except the requirement on the number of units).
All building envelope components (including walls, windows, foundation, roof, and floors) for the Benchmark shall be consistent with the HERS Reference Home as defined by the National Association of State Energy Officials (NASEO) and the Residential Energy Services Network (RESNET) in the “National Home Energy Rating Technical Guidelines,” dated September 19, 1999 (RESNET 2002). These requirements are summarized below, along with a few minor clarifications and additional requirements. References to U-values in the 1993 Model Energy