"AIA Architect" | How design adapts to the Sonoran Desert

HK Associates, the architecture firm co-led by Michael Kothke, professor of practice in the School of Architecture, and Kathy Hancox, was recently featured in AIA Architect, the digital publication of the American Institute of Architects (AIA).

The feature highlights Barrio Histórico House, an HK Associates project that serves as a case study in sustainable desert living, showcasing the firm’s innovative approach to climate-responsive design.

Article excerpt (read the full article): 

By Kathy Hancox, AIA

Image

In the heart of Tucson's Barrio Historico, a neighborhood known for its rich cultural heritage and historic Sonoran architecture, a modern residence subtly honors the past while embracing the future. Barrio Historico House offers a future-forward interpretation of traditional courtyard architecture, blending seamlessly into its context and exemplifying the benefits of sustainable, resilient design. 

A modern take on historic traditions

From the street, the award-winning Barrio Historico House by HK ASSOCIATES is modest and respectful of its surroundings. Built on an infill parcel with zero lot lines, the front facade adheres to neighborhood guidelines, with proportions and window openings that echo the rhythm of the area's historic homes. The design blends the home into the streetscape rather than competing with it. 

Step inside, and you encounter something entirely different: a serene courtyard focused on the expansive Sonoran sky and a lap pool that invites year-round indoor-outdoor living. At the heart of the home is an interplay of light, shadow, and reflection, creating framed views that constantly shift with the changing desert sky. One particularly unique feature is the rooftop periscope over the kitchen, which captures distant mountain vistas, transforming these views into a dramatic interior focal point. 

The merging of indoor and outdoor spaces, along with the careful curation of framed views, gives the home a tranquil, almost meditative quality—an oasis of calm in the bustling heart of Tucson. 

Resilience and sustainability: Building upon passive wisdom

In an era where climate change and environmental degradation are pressing concerns, Barrio Historico House is designed to withstand and adapt to these challenges by building on the wisdom of the past. Just as the design honors the physical historic context, the home's resilience and sustainability features amplify the passive environmental traditions of Sonoran courtyard architecture. 

Courtyard microclimates: The home's interior is sheltered by perimeter walls that define two courtyards, each benefiting from year-round shade that tempers the surrounding environment. In the main courtyard, a lap pool brings cooling through evaporation, moderating the hot, arid outdoor temperatures. In the smaller courtyard adjacent to the primary bedroom, lush native desert plantings—nourished by harvested rainwater—offer a similar cooling effect. 

ICF walls: Insulated Concrete Forms (ICF) were selected as an update to the Sonoran tradition of plastered, thick adobe brick walls. The high thermal mass and excellent insulation properties of ICF maintain a stable interior temperature year-round, even in Tucson's extreme heat. Situated along a busy street, the ICF walls also provide significant acoustic benefit. 

Passive solar design: The house is thoughtfully designed with minimal west-facing windows to reduce heat gain from the intense afternoon sun. The south-facing terrace of the main living space is artfully shaded to block the intense summer rays, while allowing the low-angled winter sun to enter the sun, warming the exposed concrete floor. Together with the high thermal performance of the ICF walls, the passive solar design allows the homeowners to enjoy comfortable indoor temperatures during the winter, with minimal need for active heating. 

Solar power: The power of the sun is also harnessed for energy generation via a roof top photovoltaic (PV) array to offset the majority of the home's electrical needs. In cooler months, the swimming pool also takes advantage of solar heating integration, further reducing reliance on traditional energy sources. 

Water conservation: In Tucson's arid climate, water is a precious resource. The home features a rainwater harvesting system that captures rainfall to irrigate native xeriscape landscaping. Additionally, passive stormwater management techniques, such as a decomposed granite driveway and unpaved yards, ensure that all rainwater is absorbed on-site, reducing runoff and recharging the local aquifer. 

Taken together, these sustainable design solutions—rooted in the wisdom of desert traditions—enhance daily living and comfort while reducing dependence on natural resources.