This article was originally published on The Passive House Network. The original version can be found here. For more information about rebuilding after a wildfire, visit their page here and follow PHN for updates.

Are Smoke-Tight Buildings Coming to California?
A review of California’s 2028
Building Energy code draft proposals

On January 8th, 2025, as a ring of wildfires devastated sections of Los Angeles, California’s Codes and Standards presented their first update of proposed measures being considered for the 2028 energy code. PHN was in attendance and offers the following review and comments on which measures we’ll be actively supporting if and when they progress:

Proposed measures for single-family homes, in order of our most preferred, include:

• Blower Door Testing: this measure proposes reviewing air tightness benefits and adding mandatory blower door testing requirements. The review team has proposed using non-standard modeling software to review the energy impacts of tighter building envelopes. [Hallelujah. We were jumping up and down at this proposed measure – particularly since the proposal includes using alternate software to CBECC-Res and EnergyPlus. Notably, this measure publicly flagged ‘potential software issues’ with CBECC-RES (and Energy Plus), which we have long suspected here in the Passive House community. We further note that our California affiliate, PHCA, has requested this measure be reviewed since 2010. We hope the current fires engulfing Los Angeles will finally convince all Californians that SMOKE-TIGHT construction—with measured verification —is essential in California and that we finally catch up to almost all other States where this is already required.]

• Removing Envelope measure trade-offs: this proposal will consider setting a baseline level of envelope efficiency for all buildings. [PHN heartily supports this measure of locking in baseline envelope efficiency. This will effectively replicate the Thermal Energy Demand Intensity (TEDI) measures in Massachusetts, where Passive House targets for insulation, thermal bridging, and window performance have guided code officials.]

• Exterior placement of electric domestic water heaters, especially for small buildings: this measure proposes to review exterior closet or sheltered placement of heat pump and resistance water heaters for smaller buildings without garages. [PHN endorses this proposal with reservations. Given that the placement of DHW units is driven primarily by zoning codes, where setbacks limit exterior placement options, we are skeptical of its viability. However, if California can build a connection between its energy and zoning codes, we believe this may be a groundbreaking measure. PHN notes that zoning codes nationwide are largely detached from energy impacts. Many zoning codes inadvertently lock in poor energy outcomes by prescribing complex shapes with inefficient massing. If California can bridge the gaping disconnect between zoning and energy codes, this may provide a notable opportunity for California to lead – especially for small, infill buildings, which are desperately needed everywhere.]

• Air-to-Water Heat Pump inclusion: currently, the code does not clearly define the use of air-to-water heat pump equipment as it is uncommon in California. This measure will review this equipment and provide options for inclusion. [PHN endorses the inclusion of these units, which are widely used in other states.]

• Heat pumps that work: this measure proposes to review existing installations of heat pumps to confirm efficiencies and further refine existing requirements and measures. [PHN is supportive, particularly units using lower global warming potential refrigerants.]

• A list of additional items for consideration was included, which we add below via a screenshot from the webinar. [Notable for PHN is the requirement to include heat recovery – we assume ventilation – in select climate zones, which we endorse heartily, with the caveat that recovery efficiency levels should exceed 75% to offset operational energy costs and effectively work passively.]

Our Endorsements

While PHN is pleased to endorse all these proposals, we are especially encouraged to finally see airtightness, blower door testing, and minimal envelope efficiency measures proposed. We note that not all measures always move forward. More troubling is that the measures that do move forward will only require enforcement in January 2030. (California energy codes are adopted in the title year – this one slated for 2028 – but only begin enforcement two years later.) By 2030, further floods, hurricanes, wildfires, and heat storms will impact many more Californian homes and businesses. Despite its much-vaunted leadership, California’s energy code has not kept pace with the health- and life-safety measures required for our buildings to remain occupiable and resilient in the face of an accelerating climate catastrophe. As long-time advocates for improved building resilience, we believe California’s energy code should already be looking to include other critical life safety and durability issues, such as thermal bridges and better exterior shading. The soonest these could possibly be addressed is 2031, which does not bode well.

Taking Action

As early as 2010, Passive House advocates in California politely asked the CEC to address improved building infiltration and begin to require blower door testing. This was fifteen years ago. We were relieved to finally see this measure being considered for the 2028 code cycle. While this certainly comes too late for many of our friends and colleagues in Los Angeles, we continue pushing for better building practices and adoption. PHN is now working with a growing coalition of climate and building advocates to ask our legislators to add a Passive House alternate compliance pathway into our building energy code. While this will not be an easier pathway, it will remove a barrier for those wanting to rebuild better by allowing them to use Passive House certification in lieu of the current Title 24 energy code. It will allow the CEC to add a pathway to accelerate better building practices by sending a signal to the marketplace. The bill simply removes one small barrier for front-runners to build smoke-tight, resilient homes.

We encourage you to support this collective effort by registering your support and contacting your elected officials to tell them about this draft bill to accelerate smoke-tight, safe, and climate-resilient homes.

January 9th, 2025

Bronwyn Barry, Policy Director

The Passive House Network