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).
If you are earning two points at 14%, the first round of the model should aim for a minimum 16%–17% cost savings. There may be reduction with changing design or modeling mechanism. Also remember the energy cost savings typically involve the building systems and assume 25% process loads fixed between design and baseline.
All compliance path options may require both the architectural and engineering teams to take some time in addition to project management to review the prescriptive checklists, fill out the LEED Online submittal template, and develop the compliance document.
Option 1 energy simulation often requires hiring an energy-modeling consultant, adding a cost (although this ranges, it is typically on the order of $0.10–$0.50/ft2 in North America, depending on the complexity). However, these fees produce high value in terms of design and decision-making assistance, and especially for complex or larger projects can be well worth the investment.
Option 1 energy simulation provides monthly and annual operating energy use and cost breakdowns. You can complete multiple iterations, refining energy-efficiency strategies each time. Payback periods can be quickly computed for efficiency strategies using their additional first costs. A building’s life is assumed to be 60 years. A payback period of five years is considered a very good choice, and 10 years is typically considered reasonable.
Options 2 and 3 require additional consultant time from architects and MEP engineers over typical design and documentation commitment, which means higher upfront costs.
Meeting the prescriptive requirements of Options 2 and 3 is not common practice and requires a high degree of attention to detail by your project team. (See the Documentation Toolkit for the Core Performance Guide Checklist.) These paths are more straightforward than Option 1, but don’t think of them as easy.
