With either the prescriptive or performance compliance paths, there are mandatory measures that always must be met. Mandatory measures include infiltration control, lighting systems, minimum insulation levels, and equipment efficiency. The minimum mandatory levels are sometimes superseded by more stringent prescriptive or performance requirements.
The prescriptive approach (composed of requirements described in Chapters 3, 4, 5, 6, 7, and 10) requires each component of the proposed building to meet a prescribed minimum efficiency. The approach offers little flexibility but is easy to use. If the design fails to meet even one requirement, then the system does not comply with the prescriptive approach. In this case, the performance approach provides more flexibility to the building designer for choosing alternative energy efficiency features.
A. Building Envelope. The prescriptive envelope requirements are the required thermal performance levels for each building component (walls, roofs, and floors). These requirements are described in Chapter 3. The only flexibility is if portions of an envelope component do not meet a requirement, a weighted average of the component can be used to demonstrate compliance. The stringency of the envelope requirements vary according to climate zone and occupancy type.
B. Mechanical. The prescriptive mechanical requirements are described in Chapter 4. The prescriptive approach specifies equipment, features, and design procedures, but does not mandate the installation of a particular HVAC system.
C. Indoor Lighting. The prescriptive lighting power requirements are determined by one of three methods: the complete building method, the area category method, or the tailored method. These approaches are described in Chapter 5. The allowed lighting varies according to the requirements of the building occupancy or task requirements
D. Outdoor Lighting. Outdoor lighting standards are described in Chapter 6, setting power limits for various applications such as parking lots, pedestrian areas, sales canopies, building entrances, building facades, and signs. The Energy Standards also set minimum requirements for cutoff luminaires and controls. Detailed information on the outdoor lighting power allowance calculations is in Section 6.4.
The performance approach (Chapter 11) allows greater flexibility than the prescriptive approach. It is based on an energy simulation model of the building.
The performance approach requires an approved computer compliance program that models a proposed building, determines its allowed energy budget, calculates its energy use, and determines when it complies. Design options such as window orientation, shading, thermal mass, zonal control, and building configuration are all considered in the performance approach. In addition to flexibility it helps find the most cost-effective solution for compliance.
The performance approach may be used for:
•envelope or mechanical compliance alone;
•envelope and mechanical compliance;
•envelope and indoor lighting compliance; or
•envelope, mechanical, and indoor lighting compliance.
Indoor lighting compliance must be combined with envelope compliance. The performance approach does not apply to outdoor lighting, sign lighting, exempt process load, some covered process loads (e.g., refrigerated warehouses), or solar ready applications.
Time-dependent valuation (TDV) energy is the “currency” for the performance approach. TDV energy considers the type of energy (electricity, gas, or propane) and when it is saved or used. Energy saved when California is likely to have a statewide system peak is worth more than when supply exceeds demand. Appendix JA3 of the Reference Appendices has more information on TDV energy.
See Chapter 11 if the performance approach will be used for additions and alterations.
1.6.3.1 Compliance Options
The Energy Commission has a formal process for certification of compliance options for new products, materials, designs or procedures that can improve building efficiency. §10-109 allows for the introduction of new calculation methods and measures that cannot be properly accounted for in the current approved compliance approaches. The compliance options process allows the Energy Commission to review and gather public input about the merits of new compliance techniques, products, materials, designs or procedures to demonstrate compliance for newly constructed buildings and additions and alterations to existing buildings.
Approved compliance options encourage market innovation and allow the Energy Commission to respond to changes in building design, construction, installation, and enforcement.