The latest version of California’s Title 24 (T-24) energy code was released last year. As we near 2030—a major milestone year for California’s climate targets, including doubled building energy efficiency—commercial construction project practitioners are wondering how they’ll be affected. We sat down for a Q&A with Rahul Athalye, Program Director of Codes & Standards at NORESCO, to dig deeper into the 2019 code update as well as what we can anticipate for the upcoming 2022 code cycle.
1. First, some context. Why does California need its own building energy code and how is it different from codes in other states?
The origins of California’s energy code go back almost a century when fire and seismic safety were becoming larger concerns, but the movement really gained momentum in the 1970s with the Warren-Alquist Act. Addressing concerns over the wasteful use of energy and power within the state, the act established the California Energy Commission (CEC) to address the state’s unsustainable growing energy demands through building standards. A similar movement happened at the national level with ASHRAE 90.1, but California has always had its own code. What we’re seeing in the latest version is that all codes are beginning to merge into similar requirements. There are some structure- and location-based differences, but the requirements are starting to converge.
2. What metrics does Title 24 use to verify if a building meets code or not?
There are two main compliance paths for a building:
#1: Prescriptive: Prescriptive code is just like a medical prescription: take this pill and these specific symptoms will get better. For buildings, the prescriptive path outlines specific requirements a building must follow to comply with code. If you follow the requirements, you’ll meet code.
#2: Performance: The performance path allows you to do things outside of the prescriptive requirements. For instance, a large commercial office may have a higher window to wall ratio than is outlined in code requirements. The performance path allows design teams to make various tradeoffs within the building’s features to comply without sacrificing the window to wall ratio.
This flexibility is governed by an energy budget (i.e. your building can use x amount of energy) that your project must stay below in order to comply. The primary metric for the energy budget according to T-24 code is TDV: Time-Dependent Valuation. TDV values energy differently at different times of day and this valuation also varies across the state. It accounts for climate zones and long-term forecasts to inform how much energy your project can use. New prescriptive requirements are set based on cost-effectiveness, which also uses the TDV metric, and thus both code compliance pathways are based on TDV.
3. What tools and resources does the CEC provide to help project design teams verify compliance with Title 24 2019?
Actually, a lot! There’s a hotline you can call for questions about T-24 Part-6, Blueprint newsletter about compliance and code interpretations, Energy Code Ace, which is a website developed and provided by the California Statewide Codes and Standards Program. CBECC-Com and CBECC-Res are CEC-provided tools that can be used by project teams to show compliance using the performance option within Part-6 of Title 24 code. Alternatives to the state-provided tool like IES-VE and Energy Pro are also available for project teams.
4. How does Title 24 code vary for different building types? What are the building types that are currently not covered by the code?
Any building with heating or cooling is now covered in the 2019 version, including hospitals and data centers. Hospitals were previously excluded (and regulated by other codes). Code requirements definitely vary by building type. For example, a restaurant may have large amounts of exhaust, so there are specific requirements for commercial kitchen exhaust in restaurants. Many requirements—like envelope insulation, window U-factors, and lighting—apply to all buildings, but vary slightly across individual building design.
5. What are the changes to Title 24 Part-6 code in its latest 2019 version that will impact design teams for commercial projects?
There are many changes in the 2019 version. The biggest one is the drop in lighting power allowances, which keeps up with the trend in new commercial buildings where nearly every project team uses LED fixtures. The Energy Code Ace website provides a fact sheet describing the updates in the 2019 edition. Several other requirements were brought in from ASHRAE 90.1, including waterside economizers and transfer air. Other areas of improvement in the latest update to Title 24 code include changes in air filtration requirements to address indoor air quality of spaces, updated fan power limitation requirements, and motion controls for exterior lighting.
6. How will Title 24 2019 help the state of California move towards its 2030 climate goals?
There are several policies pushing California toward decarbonization and doubling energy efficiency by 2030. T-24 2019 is a step in that direction. A lot of the new requirements introduced in 2019 will drive building energy consumption lower, moving toward increased energy efficiency.
The CEC also does an impact analysis comparing the new version of the code to the previous one to calculate the statewide energy savings, which helps illustrate how the code is moving California toward its aggressive 2030 goals. According to this study, single family homes built to meet T-24 2019 code will use 7% less energy than those built under 2016 code. Once rooftop solar generation is factored in, this number jumps up to 53% less energy than those built under 2016 code. Non-residential buildings built per 2019 code are expected to use 30% less energy than those built per 2016 code, mainly due to lighting upgrades.
7. What areas is Title 24 code looking to improve upon for its next iteration? How will design teams be impacted by these improvements?
There are a lot of measures being proposed for the 2022 code cycle, so it’s still a little early to say what will make it into the code. One likely change on the horizon is a two-metric approach to show compliance. In the past there’s been a single TDV metric that governs compliance, but the CEC is now looking to adopt a metric that supports the objectives of all the new statewide mandates. So, there may be a two-metric approach: TDV and source energy.
New requirements in the code that have not been widely implemented in the field can sometimes face challenges (for example, when daylighting control requirements were first introduced). However, design teams quickly learn to design and specify to the new requirements. Requirements in the energy code must be cost-effective, and thus, state-of-the-art measures that are not mainstream are unlikely to become part of the minimum code.
8. How are updates to Title 24 code made and how can someone in the industry be involved in the process?
Anyone can propose a change to the CEC, and they are ultimately responsible for adopting changes to the code. Cost effectiveness is always the primary criteria for new measures, but there are also many other criteria like environmental impact, impact on jobs and the economy, and supply and demand. The best way to get involved in changing the code is through the Codes and Standards Enhancement (CASE) process, which is led by utilities within the state.
9. What are reach codes and how are they different from Title 24 code?
Energy reach codes are sets of requirements that go beyond the minimum requirements of Title 24. Individual jurisdictions within the state can adopt requirements that are more stringent than the state’s energy code. The reach code requirements can be mandatory or voluntary.
10. Enough about energy codes… how do you like to spend your energy outside of work?
I love building speakers and amplifiers in my spare time! Unfortunately, the amps I like to build are not very energy efficient and use a lot of energy while producing very little output power, and so are not the best choice from an environmental perspective. But I try to make up for it in other ways, by driving less and using public transportation.
Contact our team to learn more about how to optimize your project’s energy performance.