New California ADU Legislation Taking Effect

As we all know California has needed, and has been pushing for, the construction of more housing across the state. Over the last few years, we at In Balance Green Consulting have seen a significant rise in the construction of accessory dwelling units (ADUs) in our Central Coast area. This has been widespread throughout the state since ADU laws changed and became more viable for existing lots. The cost value proposition of adding an ADU has become more favorable both to adding income-earning dwelling units and to avoiding high rent rates for a family member. At the end of 2024 Governor Newsom signed three more ADU bills that all took effect January 1st this year. Based on our work and how these will play into new projects, we thought it timely to provide a quick overview.

AB 2533 – Unpermitted ADUs and JADUs

The previous code 66332 prohibited local agencies from denying a permit for unpermitted ADUs constructed before 2018 due to non-compliance with building, state or local ADU standards. AB 2533 is an amendment to 66332 which:

·       Adds JADUs to this exception

·       Moved the construction cutoff to January 1st 2020

·       Replaced an exception that allowed denial of a permit based on health and safety of the public and/or occupants. The exception now requires that the project correct any violation of the Health and Safety Code section 17920.3 (substandard buildings) before it can be permitted.

·       Mandates new public notification requirements about the limits on local regulation, pre-application inspection by a private contractor, and substandard-building criteria.

·       Defines the scope of city inspections and limits on remedial action (Gov. Code, § 66332(a)-(f))

Our initial opinion is that much of this legislation will fall on the shoulders of public sector staff to update and improve their county’s and city’s compliance. However, the inclusion of JADUs should make the permitting process and improvement of the many unpermitted JADUs currently in use.

SB 1211 – Replacement Parking Requirements and Multifamily

The replacement parking section of SB 1211 amends the existing 66314(d)(11), which prohibited local agencies from requiring off-street parking spaces to be replaced when an existing parking structure is demolished or converted to an ADU. The amendment also prohibits replacement parking being required when an uncovered space is demolished or replaced with an ADU.

Also under SB1211, the term “livable space” was previously not defined by state ADU law, creating a difficult gray area that local jurisdictions had to navigate when addressing new ADUs proposed in basements, garages, passageways, etc. SB1211 now defines “’Livable space’… [as] a space in a dwelling intended for human habitation, including living, sleeping, eating, cooking, or sanitation.” (Gov. Code 66313€).

SB 1211 also increased the quantity of detached ADUs allowed on existing multifamily dwellings from up to two detached ADUs to now up to eight detached ADUs (or as many detached ADUs as there are primary dwelling units on the lot, whichever is less, see 66323(a)(4)(A)(ii)). A new construction multifamily project remains limited to two detached ADUs.

We always appreciate when California’s legislating bodies issue clarification within their amendments; consistency between jurisdictions and projects makes the permitting and design process much easier. We also anticipate many existing multifamily projects will be adding more ADUs in the near future.

SB 1077 – State Coastal Zone Guidance

Coastal Commission approval is a process that has proved difficult for many projects in the Central Coast and until now has been providing conflicting guidance. With SB 1077, the Coastal Commission must work with Housing and Community Development (HCD) to “develop and provide guidance for local governments to facilitate the preparation of amendments to a local coastal program to clarify and simplify the permitting process” by July 1st, 2026.

There will be at least one “public workshop to receive and consider public comments.” We recommend any interested parties participate in that workshop. Watch the Coastal Commission’s and HCD’s websites for when it will be held.

Although July 2026 seems far off, and we anticipate many projects looking for this resolution sooner, the fact it is being addressed should be reassuring.

Let's Get Some Fresh Air in Here: Operable Window Automation for IAQ

In November, I shared information about our visit to Living Places Copenhagen, a demonstration home in Denmark addressing energy efficiency, environmental impacts and indoor air quality. Using the project as a ‘living laboratory’, the Living Places team collected data throughout the project and has now published the results. Through my weeklong stay at the house and subsequent review of the data, I found the approach to, and results of, the indoor air quality (IAQ) design particularly informative and inspiring.

Typically, we rely on one of two approaches to IAQ in residential projects: an open window or mechanical ventilation.  Opening a window is great but relies on humans to be present and aware of indoor conditions. Mechanical ventilation is also crucial, especially balanced ventilation with heat recovery, but unless you’re actively heating or cooling the building, mechanical ventilation expends unnecessary energy. A third option is the one used in Living Places – operable fenestration (windows or skylights) linked to CO2 sensors to open and close automatically. In that project, the automation is also linked to temperature and humidity sensors for thermal comfort.

CO2 Data Collection and Analysis

The two occupiable homes in Living Places were designed with discreet differences so they could analyze components in isolation. For IAQ, they set up one house to only use the automated skylights, while the other house used a hybrid, adding mechanical fans as well. CO2 levels were measured with calibrated environmental sensors placed in habitable rooms of occupancy. After two months, they found that both homes meet the European Standard (EN 16798-1:2019) for indoor air quality! The European standard is generally equivalent to 750 ppm or below.

Two caveats: First, the homes are designed for effective air movement throughout all spaces, incorporating the stack effect to connect all three floors. Other homes may not have enough connectivity to achieve adequate air movement.

Second, the study was conducted over the summer in Denmark. Air conditioning was not installed or needed, based on the climate and the passive thermal strategies. The home is extremely well insulated and designed for passive heating in the winter, but the homes were not tested for IAQ with thermal comfort demands during winter conditions.

Note that, in California, operable windows and skylights do not replace the code requirement for mechanical ventilation.

Comfortable Personal Experience

For those of us staying in the house, we all felt comfortable and appreciated the indoor conditions. Throughout the day, we would see individual skylights and roof windows open and close. We had remote controllers to override the automation at any time if desired, and the units include weather sensors to automatically close skylights if there is rain. The sensors throughout the house were tied to an app that we could check at any time. Use of the app, along with directly observing the automation, helped build awareness as we ‘tuned in’ to our activity levels, the number of people in the room and changes in temperature, and the collective impact on our comfort.

Using automation for operable skylights and windows can support comfortable temperature and indoor air quality under many conditons. Our experience in the home was for Velux brand of products, but other automatic operation systems are available. One more tool in shared toolbox!

For more information on the project analysis, see “Learnings” on the Velux website.

Questions about optimizing IAQ for your project? Reach out.

All-Electric Remodel Construction Site Tour - February 11

Do you love visiting construction sites? We do too! So we’ve partnered with 3C-REN to offer tours of high performance, all-electric projects on the Central Coast.  The first will be in San Luis Obispo on February 11 at 3:30pm, visiting a major residential remodel. The builder, Mike Horgan of Cairn Collaborative, will lead us through the energy efficiency and electrification upgrades, providing first-hand information on implementation, lessons learned and best practices.

Topics covered include:

• Installation requirements and options for heat pump mechanical systems.

• Observe an installed heat pump hot water system and learn the space and location requirements and potential pitfalls to avoid.

• Discuss ventilation and indoor air quality and different options appropriate for retrofits versus new construction.

• Review wall, floor and roof assemblies for both insulation and air sealing best practices.

Project location will be provided to registered participants. To register for this free program, go to the 3C-REN calendar page HERE.

Stay tuned for tours in Santa Barbara and Ventura Counties. Have a project you would like to include on a tour? Let us know!