1.1.1 Baseline Standards

Both tax deductions and green building rating systems are based on comparing the performance of the proposed design against a code-minimum baseline building; the baseline for federal tax deductions is ASHRAE Standard 90.1-2001 and the baseline for green building ratings is ASHRAE Standard 90.1-2007 or ASHRAE Standard 90.1-2010. The baseline for Design to Earn ENERGY STAR is the median or average energy use for a similar building, in a similar climate, operated in a similar manner. The median is based on energy consumption as reported in the CBECS1 database. As COMNET is expanded to support additional purposes, additional baselines will be added as necessary.

This manual is consistent with ASHRAE Standard 90.1-2007 and 90.1-2010, but does not include addenda, approved or otherwise. ASHRAE Standard 90.1 is under continuous maintenance. This means that the committee regularly develops, approves and publishes addenda to the standard. At the time of this writing, a number of addenda to Standard 90.1 have been approved and an even greater number is pending. ASHRAE gathers these addenda includes them in the next official publication of the standard.

The modeling rules and procedures in this manual are consistent with the Performance Rating Method (PRM) in Appendix G of relevant version of ASHRAE Standard 90.1

When Standard 90.1 does not establish a baseline, the PRM often gives the rating authority the ability to establish a baseline. In some instances, this COMNET manual establishes a baseline where one does not exist in Standard 90.1, thereby assuming the responsibility of the rating authority. Examples include plug loads and commercial refrigeration. In other instances, the baseline building specification in the PRM was not specific enough and this manual expands on the definition to eliminate ambiguity.2 The purpose of these elaborations and expansions is to reduce ambiguity and offer credits for energy efficiency measures not addressed by Standard 90.1. It is not the intent of this manual to change the baseline building defined by the PRM or the underlying standards. The COMNET manual is intended to work in series with, not in parallel with the PRM.

• 1. CBECS is Commercial Building Energy Utilization Survey, which is conducted by the federal Energy Information Agency (EIA) approximately every four years.
• 2. An example is the supply air temperature reset requirement for baseline building systems 5 through 8.