Hot Tip

The model you need to develop for EAc1 is the same as for EAp2 unless you’re on a district energy system.

Besides energy modeling, you may need to use the exceptional calculation methodology (ECM) when any of the following situations occur: 

The energy model itself will not account for any change in plug loads from the baseline case, even if your project is making a conscious effort to purchase Energy Star or other efficient equipment. Any improvement made in plug loads must be documented separately, using the exceptional calculation methodology (ECM), as described in ASHRAE 90.1-2004.

LEED divides energy-using systems into two categories:

For existing buildings, the baseline energy model can reflect the pre-renovation features rather than a minimally ASHRAE-compliant building. This will help you achieve additional savings in comparison with the baseline.

Energy modeling can inform your project team from the start of design. Early on, review site climate data—such as temperature, humidity and wind, available from most energy software—as a team. Evaluate the site context and the microclimate, noting the effects of neighboring buildings, bodies of water, and vegetation. Estimate the distribution of energy across major end uses (such as space heating and cooling, lighting, plug loads, hot water, and any additional energy uses), targeting high-energy-use areas to focus on during design.  

Use simple computer tools like SketchUp and Green Building Studio that are now available with energy analysis plug-ins to generate a first-order estimate of building energy use within a climate context and to identify a design direction. Note that you may need to refer to different software may not be the one used to develop complete the whole building energy simulations necessary for LEED certification.

The architect, mechanical engineer, and lighting designer need to familiarize themselves and confirm compliance with the mandatory requirements of ASHRAE 90.1-2004, sections 5–9.

Some energy conservation measures, such as energy recovery ventilation or a highly insulated building envelope, add to both construction and design costs, though with an integrated design process these costs might be recouped through savings elsewhere, such as through reducing the size of the mechanical system. The most effective approach is to have your building owner and design team together evaluate both the first costs of the energy-saving measures and their effectiveness at reducing operating costs. 

Under Option 3 for compliance with the Core Performance Guide, you can earn 2–5 points. It’s a good option if your project is smaller than 100,000 ft², is not health care, warehouse or laboratory and you’d rather not commit to energy modeling (Option 1).