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1.1 Purposes

The COMNET energy efficiency calculation process serves multiple purposes, including the following:

  • Establishing eligibility for federal tax deductions per §179D of the Internal Revenue Service (IRS) code;
  • Calculating percent savings for point eligibility related to green building rating systems; and
  • Estimating annual energy use for a building in the design phase for the purpose of Design to Earn ENERGY STAR.

COMNET software may be accredited for one or more purposes. Depending on the purpose, the process is somewhat different. Table 1.1-1 summarizes the major differences in calculation procedures for the currently supported purposes. These differences are described in more detail in the sections that follow.

Table 1.1-1: "Differences in Calculation Procedures by Original Purposes"


 Tax Deductions LEED 2.2
 LEED 2012 Design to Earn ENERGY STAR
Baseline Standard ASHRAE Standard 90.1-2001 ASHRAE Standard 90.1-2007 ASHRAE Standard 90.1-2010 CBECS Median Energy Use
Operating Assumptions Prescribed Neutral Dependent Neutral Dependent Default
Percent Savings Energy Use Regulated Only All Energy Use All Energy Use Not applicable