If you change or go through value-engineering on any specifications, such as the solar-heat gain coefficient of glazing, for example, be aware of impacts on mechanical system sizing. Making changes like this might not pay off as much as it first appears. Of equal importance, make sure that any scope reductions or design changes don’t jeopardize meeting the ASHRAE 90.1-2004 requirements.
All compliance path options may require both the architectural and engineering teams to take some time in addition to project management to review the ASHRAE prescriptive checklists, fill out the LEED Online submittal template, and develop the compliance document.
Don’t plan on using onsite renewable energy generation (see EAc2) to make your building energy-efficient. It is almost always more cost-effective to make an efficient building, and then to add renewables like photovoltaics as the “icing” on the cake.
Remember that the ASHRAE 90.1-2004 mandatory provisions and prescriptive and performance requirements are a starting point for energy efficiency. Plan to exceed these to earn points under EAc1.
A poorly designed envelope with a high-tech HVAC system is not, on the whole, efficient or cost-effective. Start with building orientation and passive design features first when looking for energy efficiency. Also look at envelope design, such as energy-efficient windows, walls and roof, before looking at HVAC and plug loads. HVAC may also be a good place to improve performance with more efficient equipment, but first reducing loads with smaller equipment can lead to even greater operational and upfront savings.
If you registered before 2007, you have a lower threshold and can follow the AHSRAE 90.1 2004 prescriptive compliance path. You do not technically have to earn any points in EAc1.
Check the registration date of your project. If you registered after June 2007, you have to achieve two points under EAc1 as per USGBC addenda. There is lot of synergy between EAc1 compliance and meeting this prerequisite because of this reason. The prerequisite’s energy-reduction target (for EAc1 option 1) of 14% is not common practice and is considered beyond code compliance.
You will need to comply with the mandatory requirements of ASHRAE 90.1-2004, to bring your project to the minimum level of performance. The ASHRAE 90.1-2004 User’s Manual is a great resource, with illustrated examples of solutions for meeting the requirements.
