Next year will bring another update to California’s well-known building code, Title 24, specifically Title 24 Part 6 the building energy efficiency standards. The Title 24-2019 standard will go into effect on January 1, 2020 and will apply to any project that goes in for its first plan check on January 1, 2020 or later. Title 24-2019 continues to raise the bar that its predecessors set—moving California toward a more energy efficient (and eventually net zero) future. Within Title 24 there are separate codes for low-rise residential, which the code defines as 3 stories or less, and all other types of buildings. We’re going to focus on the nonresidential code updates here.
But, before going into code updates it’s important to understand the three types of code requirements in Title 24: mandatory, prescriptive, and performance. Mandatory measures are just what they sound like, where every single building must meet that measure, unless they conform with an exception that is explicitly listed within the code. Prescriptive and performance measures depend on what approach your project is taking to comply with Title 24. The prescriptive path allows projects to meet each and every prescriptive requirement in the code in order to comply with Title 24, while the performance path allows projects to take a comprehensive whole building approach. With the performance path you can substitute lower performing glazing for higher performing HVAC, as long as the trade off is at least as energy efficient. Most new construction projects will take the performance approach, since it lets a project use a window to wall ratio (WWR) above 40%, have different envelope assemblies, and can avoid any potentially problematic prescriptive requirements. Tenant improvement projects regularly use the prescriptive approach since they only need to meet the lighting and HVAC requirements, but can use the performance approach as well.
The updates in Title 24-2019 fall into these categories as well. Of the major changes, all HVAC systems, whether a large air handler in an office building or a small fan coil in a hotel room, will require MERV 13 filters. Previously the requirement was MERV 8 filtration and that was in the California Green Building Code. MERV 13 filters are standard in commercial office buildings, so this change will have minimal impact for those building spaces. However, high-rise residential and hotel buildings typically use MERV 8 filtration, so this will be a major change for those spaces. Argento/Graham talked to a mechanical contractor who is installing MERV 13 filtration on all heat pumps in one of our high-rise residential projects. The mechanical contractor said that as long as the correct equipment is chosen during design and the design engineers account for the MERV 13 filters that it’s easy to build. All of the design engineers we know will easily be able to accommodate this change and design accordingly, so the change to MERV 13 won’t be too difficult. The only potential issue is that it might eliminate a few HVAC models as options, but we’re sure that all or most HVAC manufacturers will create a model that can handle MERV 13.
Another major change in the 2019 code is the reduction in allowed interior lighting power densities. The cuts are quite drastic compared to the 2016 code. For example, nonornamental lighting in a family restaurant will be limited to 0.50 watts per square foot, while the 2016 code allowed 1.0 watts per square foot. Open office areas will be limited to 0.60 watts per square foot while the 2016 code allowed 0.75 watts per square foot. The new allowances are all achievable – otherwise they wouldn’t be in the code – but it will take a thoughtful lighting design to meet code. One area where issues may arise could be for luxury projects with lighting designers. A darker color scheme and a high-end lighting design may not be able to achieve the required lighting power densities. The new code may force designs to make energy efficiency as important as illuminance and aesthetics.
Additionally, interior lighting is one of the items that can be traded off when a project takes the performance approach to compliance. Right now, most projects will easily meet the lighting power density requirements, which can allow that project to make a tradeoff elsewhere. One common energy tradeoff is for the WWR, since code limits the WWR to 40%. With the new lighting power density requirements projects won’t be able to take as much credit, which will require projects to decrease their WWR or to purchase higher efficiency HVAC systems. I can already hear architects practicing their HVAC sales pitches.
Another major change is that the energy code now covers more occupancy types. Specifically, I-1 and I-2 have been added, which cover hospitals, nursing homes, assisted living facilities, and much more. These occupancy types have a good number of exemptions throughout the code, but they are now covered and will require an energy efficient design.
There are many more changes to the 2019 energy code, so please reach out to Argento/Graham if you’d like to learn more or prepare your project for Title 24-2019.