The California wildfires are still raging in the Los Angeles area a week after they began. The stories of area residents who lost everything are heartbreaking.
Against this catastrophic backdrop, some lucky houses were spared; For one reason or another, these residents' homes are miraculously still intact.
But how can that be? Of course, there's advice on how to fireproof your home, with experts recommending everything from landscaping tips to the benefits of sprinklers.
However, some knowledgeable architects recommend investing in a so-called “passive house”. Although still a relatively new trend on the market, these types of homes are designed to be extremely environmentally friendly – and have some protection against fire damage.
“Passive House” survives fire in California
The latest statistics from California estimate that over 40,000 acres have burned as of January 14th. The first Pacific Palisades fire is 17% contained, with nearly 24,000 acres decimated.
A week after the fires began, winds were predicted to return at levels that could “lead to extreme fire behavior from the fires or turn any new spark into a raging inferno,” according to CNN.
Greg Chasen's Pacific Palisades home, which he built in 2024, still stands while neighboring homes burned. The house on Iliff Street was the “only one” that “remained intact,” Mansion Global reported.
“Without multiple fire-resistant design strategies, the home would have been destroyed,” Bloomberg reported.
Chasen, an architect who designed the home, said the house, which he built “for a dear friend,” has several fire-safety features. Some of these follow the principles of passive house design.
How a passive house is built
To officially qualify as a passive house, a home must meet certain criteria set by the International Passive House Association. The apartment must use 86% less energy for heating and 46% less energy for cooling than other standard-compliant buildings in the same climate.
To reduce or even eliminate the need for heat in winter and air conditioning in summer, a Passive House is built to be airtight, with strong external insulation, triple-glazed windows, and construction methods that ensure no heat is transferred through the outside of the building. No outside air enters and no inside air escapes.
This airtight construction is one of the reasons the house was able to withstand a fire.
As Bloomberg reported, the home has no eaves, overhangs or vents in the attic “for sparks to travel into the roof, which is made of metal and has a fire-resistant backing.”
Additionally, Chasen’s fire protection selection includes “a sheltered area free from vegetation, fenced in by cast-in-place concrete garden walls.”
What are the passive house principles?
While nothing is completely fireproof, there are several ways to protect a home.
For example, adhering to the five Passive House principles required for certification can be helpful. According to Passive House Accelerator, these are the principles:
- Super insulated envelopes
- Airtight construction
- High performance glazing
- Thermal bridge-free details
- Ventilation with heat recovery
Zachary Semke, principal at Passive House Accelerator, tells Realtor.com® that many key principles of Passive House design help make buildings resilient to fire and smoke.
“An airtight construction prevents embers from being sucked into the building envelope,” says Semke. “Simpler shapes (fewer zigzags, bulges, etc.) mean fewer nooks and crannies for embers to get stuck in, as well as a smaller overall area exposed to fire hazard.”
Stay up to date with NYP's coverage of the horrific fires in the LA area
Ignacio Rodriguez, CEO of IR Architects, designed nine homes currently in the Palisades-Malibu fire zone, eight of which were still standing at press time. He says several passive strategies are now part of California's Title 24 energy law, and his company incorporates these practices into its home designs.
Rodriguez, who was forced to evacuate his own home during the Hurst fire, explains that tighter enclosures are the passive practice most relevant to fire resistance.
“The main goal is energy efficiency to prevent heat and cold loss in the home, but a tight seal also increases resistance to fire,” he says.
Additionally, he says windows are “key to the success of fires.” While a structure can withstand flames, heat and wind can blow out windows.
“We have found that aluminum-framed windows are more durable than vinyl-framed windows,” he adds.
In addition, Rodriguez points out that his company encourages customers to install one-hour fire protection membranes behind structural wood and to apply a fire-retardant coating to exterior wood siding.
Finally, as Semke notes, these buildings also have energy recovery ventilation systems (HRVs and ERVs) that can be equipped with filters to remove smoke particles and odors. This protects the health and well-being of residents and building interiors from smoke damage.
Costs for passive houses
States like New York, Massachusetts and Pennsylvania were among the early adopters of passive houses. According to the Passive House Network, “16,000 Passive House multi-family houses (apartments or terraced houses) were built or are under construction nationwide” in 2023.
According to Semke, there are currently 12 million square feet of Passive House-certified buildings in the United States. They are a combination of single-family and multi-family homes. These projects are certified by one of two independent certification bodies: Phius (based in Chicago) and Passive House Institute (based in Darmstadt, Germany).
However, one of the biggest drawbacks to these structures is their upfront cost.
According to Semke, these single-family homes are typically 5 to 10% more expensive with cost-optimized planning. However, the upfront investment brings ongoing savings on utility bills.