Casa Águila: A Resilient, Self-Sufficient Solution to Wildfires
In 2007, the Witch Creek fire destroyed 1,000 homes in northern San Diego’s San Pasqual Valley. When it came time for Amy McQuillan and Pete Beauregard to rebuild their house, they decided to do it with a purpose.
Today, their new 3,129-square-foot, 4-bedroom, 5-bath residence serves as a prime example of what’s possible when it comes to building fire-resilient structures. The couple achieved this with the help of architect Andrew Wilt, who designed the luxurious home, and Alliance Green Builders, who constructed it.
According to the home’s official website, “the homeowners, architect, and builders made fire-resistance a top priority incorporated into the architecture and material selection.” Fire-resistant construction materials, including stucco and concrete walls, metal roofing, high-impact windows, and stone and tile ground cover serve to make “Casa Águila” even more resilient.
The single-story ranch-style property, completed in 2016, is named after the golden eagles that soar through the surrounding hills, marking the first house in the entire county to be certified by the Passive House Institute US. Passive home design is a building standard that takes factors like energy efficiency, comfort, affordability, and ecological concerns into consideration — all of which are especially important in Southern California, where drought is ongoing and wildfires cause power outages that can last for days.
The home’s shell is both energy-efficient and fire-resistant. This one-two punch was achieved with help from the Department of Energy’s Zero Energy Ready Home program (ZERH). The wood framing within was treated with borate, a naturally-occuring compound that is commonly used to protect wood from termites, though it also prevents combustion while suppressing smolder.
Additionally, the interior walls and ceilings were fitted with sheets of plastic containing bio-based, phase-changing gel packets, which themselves offer an energy-efficient way to stabilize interior temperatures. More specifically, the gel within them “phases,” cooling the home when it melts and warming it back up when it solidifies.
“Bulletproof” Windows and Doors
You might think that a building’s exterior would be the first thing to catch during a wildfire, but because Southern California’s fierce Santa Ana winds are capable of lifting up debris and breaking windows, embers can actually spark up inside of homes, too. For that reason, Casa Águila has been equipped with Passive House-rated, German-manufactured Unilux windows and doors. The glass on these windows is tempered and protected by a laminated “bulletproof” outer layer, the likes of which should be able to withstand rocks and other wind-blown debris.
Self-Sufficient Means Natural-Disaster-Ready
Casa Águila’s average annual savings compared to that of a standard new home (due primarily to energy efficiency) is $11,700. All California DOE ZERHs are evaluated using the California Energy Design Rating (EDR), and this home received an incredibly low EDR of -92.
A 360-square-foot solar thermal collection system on the roof provides the home with radiant floor heat and hot water. With climate change in mind, two backup systems have been put in place to provide air and water heating and cooling. Builder Jeff Adams explains: “the system has been designed for a climate that could be dramatically different in 100 years or more.”
Drought-resilience and water self-sufficiency were achieved using five 10,000-gallon rainwater-collection tanks. Four more 10,000-gallon tanks collect storm water, while a fifth additional tank collects graywater from the washing machine, sinks, and showers. This water is filtered and reserved for irrigation and fire-suppression purposes. Blackwater from the kitchen sink and toilets is released into a septic tank before being aerated, filtered, and pumped into a final 1,000-gallon tank (also for irrigation use).
474 square feet of photovoltaic panels have been employed for electricity, each of them maximizing efficiency even on the rare cloudy days. The hill above Casa Águila is the site of the home’s other energy-collector, a helical, 45-foot-tall, 3.2-kW wind turbine. In total, the residence runs off of twenty twelve-volt solar batteries and can generate power for over twelve hours a day.
In 2016, the home gained LEED Platinum status and won the 2017 Department of Energy’s Housing Innovation Award. The homeowners continue to innovate and educate their community through home tours and workshops.