Single-Family Home

Startup’s Prefab Home Design Has a Carbon-Negative Footprint

Seattle’s Olson Kundig has a long history creating houses with wood, stretching back almost 60 years. It’s that experience that led Mountain View, California-based Aro Homes to hire the architecture firm to design a 3,000-square-foot home that is manufactured through a hybrid oﬀ-site/on-site construction strategy.

Aro Homes utilizes the prefab light-frame approach to set it itself apart from a housing construction market it considers to be inefficient, slow, and costly. Optimized by machine learning, its factory-based construction promises a drastically reduced construction timeline and carbon-negative footprint.

The two-story house features a clean and simple contemporary expression inside and out. “We strike this balance where it’s a pretty broadly appealing aesthetic,” Olson Kundig Principal Blair Payson says. “It could be a good neighbor next to a Craftsman; it could be a good neighbor next to a mid-century modern house.”

Aro Homes

Photo Credit: Matthew Millman

As designed, neither the modularity nor the prefabrication is obvious in the house. While it’s primarily built in a factory, the Aro House uses conventional stick framing methods. The team felt that prefabrication and modular construction was enough innovation. “The early decision was, ‘Let’s not do experimental construction because prefab modular is plenty enough to tackle,’” Payson says. Wood’s versatility ensured that their design could be realized even with conventional materials.

Construction on Aro homes is done indoors on a regular schedule that’s not subject to the whims of the weather. “From a labor perspective, there’s this predictability about always going to a dry condition site,” Payson says. “It’s more of a nine to five approach to working. [It’s] more predictable, which is different for that trade.”

The first Aro House is composed of seven modules of 15 feet by about 30 feet, sized so that each module can fit on the back of a flatbed truck. Houses destined for the Bay Area are prefabricated in Sacramento, but as Aro Homes expands, the plan is to locate factories within a 70-mile radius of a particular market.

Building Systems Diagram

The freestanding house features four bedrooms and an oﬃce space that can become a fifth bedroom. The architects employed three steel beams to create a few big spans, but otherwise it’s all wood-framed construction. The exterior is clad in light-stained horizontal wood siding, a material that ages naturally and brings the warmth and character Olson Kundig seeks in its residential work. One slight deviation from conventional developer homes in the region: wood floors throughout in lieu of the usual laminate.

“It’s one of the most high performing projects we’ve ever done as an office,” Payson says. The home uses 67% less energy than the American Institute of Architects (AIA) 2030 Challenge Baseline for energy performance. A standard roof-mounted photovoltaic solar array will produce more electricity than the house uses in a year. The Aro Home will be carbon neutral after about 18 years, having offset its embodied carbon at that point—afterwards, the structure will generate about 20% more energy than it uses.

Aro Homes

Photo Credit: Matthew Millman

To date, Aro Homes is building the Olson Kundig–designed houses speculatively, and is already reducing the typical 18-month timeframe to buy a lot and build a house into a three-month process from start to finish.

Dreams of large-scale prefabricated design have thwarted architects and builders for more than a century. Aro Homes and Olson Kundig may just have discovered how to unlock that dream’s potential by reimagining how to meld traditional and innovative techniques to create a series of attractive new homes.