The California wildfires are still ravaging the Los Angeles area a week after they started. The stories of residents who live in the area and have lost everything are heartbreaking.
Against this catastrophic backdrop, a lucky few houses were spared; for one reason or another, these residents’ homes are miraculously still intact.
But how can that be? Sure, there is advice on how to fireproof your home, with experts recommending everything from landscaping tips to the benefits of sprinklers.
However, some architects in the know recommend investing in what’s called a “passive home.” Though still a fairly new trend on the market, these types of homes are designed to be incredibly eco-friendly—and benefit from having some protection against fire damage.
‘Passive house’ survives California fire
The latest stats out of California project that over 40,000 acres have been scorched as of Jan. 14. The initial blaze in Pacific Palisades stands at 17% containment, with nearly 24,000 acres decimated.
A week after the fires started, winds were predicted to return with a force, which “could cause extreme fire behavior in the blazes or turn any new spark into a raging inferno,” according to CNN.
Greg Chasen’s house in Pacific Palisades, which he built in 2024, still stands while the neighboring homes burned down. The house on Iliff Street is the “single one” that “remains intact,” Mansion Global reported.
“If it weren’t for several fire-resilient design strategies, the home would have been destroyed,” Bloomberg reported.
Chasen, an architect who designed the house, said the home he built “for a dear friend” boasts several fire-proofing features. Several of these follow the principles of passive home design.
How a passive house is built
To qualify officially as a passive house, a home must meet certain criteria set by the International Passive House Association. The dwelling must consume 86% less energy for heating and 46% less for cooling compared with other code-compliant buildings in the same climate.
To reduce or even eliminate the need for heat in the winter and air conditioning in the summer, a passive house is built airtight, using strong exterior insulation, triple-pane windows, and construction methods that ensure no heat is transferred across the exterior of the building. No outdoor air seeps in, and no indoor air escapes.
This airtight construction is one of the reasons the house could withstand a blaze.
As Bloomberg reported, the house does not have eaves, overhangs, or attic vents “to allow sparks to get inside the roof, which is metal, with a fire-resistant underlayment.”
In addition, Chasen’s fire-proofing choices include “a protected area free of vegetation, fenced off by cast-in-place concrete garden walls.”
What are the passive house principles?
While nothing is entirely fireproof, there are several ways to protect a house.
For instance, following the five passive house principles—needed for a certification—can help. According to Passive House Accelerator, these are the principles:
- Superinsulated envelopes
- Airtight construction
- High-performance glazing
- Thermal-bridge-free detailing
- Heat recovery ventilation
Zachary Semke, director at Passive House Accelerator, tells Realtor.com® that many essential principles of passive house design help make buildings resilient to fire and smoke.
“Airtight construction helps stop embers from being sucked into building envelopes,” says Semke. “Simpler forms (fewer zigs and zags, bump-outs, etc.) mean fewer nooks and crannies for embers to take hold, plus less overall surface area exposed to fire risk.”
Stay up to date with the NYP’s coverage of the terrifying LA-area fires
Ignacio Rodriguez, CEO of IR Architects, designed nine houses currently in the Palisades-Malibu fire’s path, eight of which were still standing at press time. He says several passive strategies are now part of California’s Title 24 energy code, and his firm embeds these practices in its residential designs.
Rodriguez, who was forced to evacuate his own home during the Hurst fire, explains that tighter envelopes are the passive practice most relevant for fire resistance.
“The primary intent is energy efficiency to prevent heating and cooling loss from the home, but tight sealing also elevates fire resilience,” he says.
In addition, he says that windows are “keys to fire success.” While a structure might withstand flames, heat and wind can blow out windows.
“We’ve found that aluminum-framed windows are more resilient than vinyl frames,” he adds.
In addition, Rodriguez notes that his firm encourages clients to install one-hour fire membranes behind structural wood and treat exterior wood trim with a fire-retardant coating.
Finally, as Semke notes, these structures also feature energy recovery ventilation systems (HRVs and ERVs), which can be fitted with filters to remove smoke particulates and odors. This protects the health and well-being of occupants and building interiors from smoke damage.
Passive house cost
States such as New York, Massachusetts, and Pennsylvania have been early adopters of passive houses. As of 2023, “16,000 units of Passive House multifamily housing (apartments or townhomes) were built or are in the process of construction nationwide,” according to the Passive House Network.
There are currently 12 million square feet of passive house-certified buildings in the U.S., according to Semke. They’re a combination of single-family and multifamily buildings. Those projects are certified by one of two independent certifying bodies: Phius (based in Chicago) and Passive House Institute (based in Darmstadt, Germany).
Yet, one of the most significant drawbacks of these structures is their up-front costs.
According to Semke, these single-family homes are typically 5% to 10% more expensive when designed with cost optimization in mind. However, the upfront investment brings ongoing savings in utility bills.