As the State of California increases energy performance standards through the triennial code cycle, early budgeting figures are constantly in flux. Project estimators and financial analysts must either rely on their own understanding of the changes in energy codes and/or engage with a team of designers or contractors to help assess first cost financial impacts.
Early energy modeling can save projects hundreds of thousands of dollars, if not more, and early energy design simulations can help with reducing additional stress on timelines and deliverables. Moreover, changes to prescriptive code required building components can be virtually modified to assess first costs and/or return on investment.
One recent example is a developer who saved approximately $900k in first costs by utilizing code and energy expertise to intelligently model prescriptive requirements to achieve energy code compliance. Without early energy modeling, the project would have installed a piece of equipment that is costly to build and operate.
Here are four energy performance areas that tend not to drastically alter design while delivering favorable energy compliance results:
Readjusting glazing factors after windows and walls locations are established is a simple modification. These adjustments are typically limited to modifying the specifications of products without the need to modify product dimensions, thus preventing cumbersome adjustments to the drawings. If the compliance margin for the building is strong, a different kind of window could be specified to help reduce first costs.
Insulation in Building Envelope
Proper insulation design strategies are critical for preventing heat transfer between conditioned and unconditioned space. The energy code is prescribing continuous rigid insulation for both wood frame and metal frame construction. Exterior double walls or staggered stud walls may help offset a lack of rigid insulation. High performance attics for low-rise residential projects and spandrel systems for metal-framed construction could improve performance with Title 24 energy modeling.
Domestic/Service Hot Water Systems
If the building envelope is providing a compliance challenge, energy credits can be earned through domestic hot water generation. A central high efficiency boiler is typically the simplest upgrade with solid return-on-investment since ownership is typically responsible for heating costs. Adding solar hot water pre-heat will provide solid compliance improvements, deliver rapid payback, and extend the life of the boiler systems. Roof space will need to be considered early.
Higher efficiency mechanical systems are available and costs may be reduced over time. Energy performance can be greatly improved through the careful assessment and implementation of mechanical systems while considering budget friendly alternatives above.
On some projects, under the current California 2016 Energy Code cycle, HERS (Home Efficiency Rating System) testing of mechanical systems can be taken to help improve the energy score and deliver a quality assurance process on installation and performance. HERS testing is a lower cost energy efficiency option than upgrading windows or insulation.
Your building is a system, and that system is impacted as each energy-related component is modified. Lights produce heat, which increases HVAC requirements in the summer. Well-sealed and well-insulated walls and ceilings reduce heating and cooling loads, which could help reduce the size of systems to be installed.
With budget and energy code compliance in mind, early energy modeling in schematic or design development can help remove blind spots and better align budget expectations.
Contributing Writer: Alejandro Gamas, Energy Modeler