Building Envelope
The Standards have both mandatory measures and prescriptive requirements that affect the design of the building envelope. These requirements establish a minimum level of performance, which can be exceeded by advanced design options or construction practices. Those design options that are recognized for credit in the performance approach are called compliance options. Compliance options have eligibility criteria that must be satisfied before compliance credit is offered.
Lighting
Indoor lighting is one of the single largest consumers of energy (kilowatt-hours) in a commercial building, representing about a third of electricity use. The objective of the Standards is the effective reduction of this energy use, without compromising the quality of lighting or task work. The Standards are the result of the involvement of many representatives of the lighting design and manufacturing community, and of building departments across the state. A great deal of effort has been devoted to making the lighting requirements practical and realistic.
The outdoor lighting and sign energy standards conserve energy, reduce winter peak electric demand, and are technically feasible and cost effective. They set minimum control requirements, maximum allowable power levels, minimum efficacy requirements, and require cutoff classification for large luminaires. The lighting power allowances are based on current Illuminating Engineering Society of North America (IESNA) recommendations for the quantity and design parameters of illumination, current industry practices, and efficient sources and equipment that are readily available. Data indicates that the IESNA recommendations provide more than adequate illumination, since a 2002 baseline survey of current outdoor lighting practice in California suggests that the majority of establishments currently are illuminated at substantially lower levels than IESNA recommendations. The Standards do not allow tradeoffs between outdoor lighting power allowances and interior lighting, HVAC, building envelope, or water heating.
HVAC
The objective of the Standards requirements for mechanical systems is to reduce energy consumption while maintaining occupant comfort. These goals are achieved by: 1) Maximizing equipment efficiency, both at design conditions and during part load operation 2) Minimizing distribution losses of heating and cooling energy 3) Optimizing system control to minimize unnecessary operation and simultaneous use of heating and cooling energy. The Standards also recognize the importance of indoor air quality for occupant comfort and health. To this end, the Standard requirements for outdoor air ventilation must be met during all operating conditions.
Water Heating
Water heating energy use is important in buildings. Standby loss is typically more than a quarter of a gas storage type water heater system's total energy use. However, when the system fuel is natural gas, there are no generation losses as are associated with electricity. Fuel type is very important in determining water heating energy use. While natural gas, LPG or oil can be burned directly to heat water, electricity is typically generated in a power plant. Approximately two thirds of the source energy used to generate electricity is lost in the generation and distribution processes. Any electric water heating system must automatically account for the inefficiency of the fuel type. Standard electric water heaters are not considered energy efficient for this reason. Electric heat pump water heaters, however, are closer to the efficiency of typical gas systems, because they use the outdoor air as a heat source in heating water. The relative values of the losses associated with different sources of energy are integrated into the TDV multiplier.