Control technology is constantly increasing in sophistication. Innovation is leading the way to energy savings and reliable ease of use of complicated building features. As a result, interest is growing in smart controls that both speak to multiple features within the building, such as HVAC and lighting, and also help manage the energy use of a building.
The 2022 California Building Energy Efficiency Standards, also known as Title 24, Part 6 and referred herein as the Energy Code, exists to increase energy efficiency, reduce the carbon footprint of buildings, encourage energy innovation, and advance state energy policies. This article explores the minimum building control requirements of the Energy Code and what optional controls or control features can be used for compliance flexibility when using the performance approach as “extra credit.” Project teams anywhere, including outside of California, should consider following Energy Code control requirements to achieve extra energy savings.
Projects that are required to pull a building permit must complete two overarching steps to comply with the Energy Code.
First, they must meet all mandatory requirements. Most building features and systems have minimum requirements that must be met either by the manufacturer of the equipment or by the designer of the building. For example, HVAC equipment has minimum efficiency requirements that are established by the U.S. Department of Energy Appliance and Equipment Standards. Circumventing mandatory requirements is impossible. However, designers can choose to exceed the minimum HVAC requirements by specifying HVAC equipment with higher-than-minimum requirements that could be used for compliance flexibility via the performance approach.
Second, the project must comply via one of two methods: the prescriptive approach or the performance approach.
- Prescriptive approach: The prescriptive approach is considered the most direct path to compliance. It is a set of prescribed performance levels for various building components, where each component must meet the required minimum efficiency. This is a simple method of showing compliance; no energy modeling software is required to document compliance to the Energy Code. For example, in commercial buildings, economizers are prescriptively required for HVAC equipment over a certain size. Designers can choose to specify economizer equipment that exceeds the prescriptive economizer requirements and gain extra credit via the performance approach, providing compliance flexibility for the project.
- Performance approach: The performance approach builds on the prescriptive approach by allowing energy allotments to be traded between building systems. Teams can propose energy use trade-offs among features of the building envelope, domestic water heating, and space heating and cooling equipment serving the conditioned spaces of the building. This compliance approach requires using energy modeling software that has been approved by the California Energy Commission (CEC).
When considering how smart controls can and should be used to support a building, the design team must consider the needs of the building operator, tenants, and owner. Some control improvements can provide compliance extra credit when using the performance approach. Other control improvements can provide comfort, ease of use, and utility savings above and beyond what is regulated by the Energy Code.
The following tables summarize most of the Energy Code controls requirements associated with single-family, multifamily, hotel/motel, and nonresidential projects, while also suggesting how a design team may claim credit via the performance approach when design flexibility is needed or to support the owner’s desire for a smart building.
As the building industry and Energy Code evolves, more opportunities will arise for manufacturers and designers to go beyond minimum requirements, increase potential energy savings for owners, and improve occupant comfort. Smart controls are continuously being integrated into more appliances, including dishwashers, refrigerators, washers and dryers, and HVAC equipment; and they provide the opportunity to improve energy savings when correlated to utility time-of-use rate schedules. What will manufacturers come up with next?