If your project combines new construction and existing building renovation then whatever portion contains more than 50% of the floor area would determine the energy thresholds.
Hotels, multifamily residential, and unconventional commercial buildings may not be eligible for either Option 2 or Option 3, because the prescriptive guidance of these paths was not intended for them. Complex projects, unconventional building types, off-grid projects, or those with high energy-reduction goals are better off pursuing Option 1, which provides the opportunity to explore more flexible and innovative efficiency strategies and to trade off high-energy uses for lower ones.
Option 3: Prescriptive Compliance Path: Advanced Buildings Core Performance Guide is another, more basic prescriptive path. It’s a good option if your project is smaller than 100,000 ft2, cannot pursue Option 2 (because there is not an ASHRAE guide for the building type), is not a healthcare facility, lab, or warehouse—or you would rather not commit to the energy modeling required for Option 1. Your project can be of any other building type (such as office or retail).
Complying with Option 2 earns 4 points, and with Option 3, 2-5 points and Option 4, 1 point. If you are committed to greatly reducing energy usage and earning a higher number of points, then follow Option 1 for compliance with both EAp2 and EAc1.
Option 2: Prescriptive Compliance Path: ASHRAE Advanced Energy Design Guide for Small Office Buildings 2004 refers to design guides published by ASHRAE for office projects of 20,000 ft2 of less. These guides outline strategies to reduce energy use by 30% from ASHRAE 90.1-2001 levels, or an amount equivalent to a 10%–14% reduction from the ASHRAE 90.1-2004 standard. If you choose this compliance path, become familiar with the list of prescriptive requirements and commit to meeting them.
Option 1: Whole Building Energy Simulation offers the most points, but it requires estimating the energy use of the whole building over a calendar year, using methodology established by ASHRAE 90.1-2004, Appendix G. Option 1 establishes a computer model of the building’s architectural design and all mechanical, electrical, domestic hot water, plug load, and other energy-consuming systems and devices. The model incorporates the occupancy load and a schedule representing projected usage in order to predict energy use.
Find the best credit compliance path based on your building type and energy-efficiency targets. Use the following considerations, noting that some projects are more suited to a prescriptive approach than others.
An automated building management system (BMS) can significantly reduce building energy use by turning down air conditioning and turning off lights during unoccupied hours, along with other similar measures. Occupancy sensors, timers, and temperature sensors feed into the system to switch off lights and fans when not needed. Note that controls can be counted towards energy reductions only through energy modeling.
Note that energy efficiency is not just about efficient boilers and chillers. To achieve high targets, the design of the building has to help reduce dependence on mechanical heating and cooling throughout the year, through measures like orientation, moderate glazing areas, and self-shading.
