While Harvey West and DBA’s previous affordable housing projects share many similarities, there are some significant differences needed to meet this project’s goals. DBA has been working with RDH Building Science as its Phius consultant to optimize the envelope and mechanical systems. In keeping with Phius requirements, the Harvey West project will rely on ERVs—one per residential floor—to supply constant fresh air while minimizing heat gains and losses through the ventilation system. Another difference this project will feature is a layer of continuous exterior insulation—but only one inch. At present a mineral wool product is specified.
WUFI modeling is showing that double-pane windows will be sufficient to meet the heating and cooling criteria. Custom-designed folded metal panels will shade the south-facing windows, while a vertical shade on the western facade will reduce overheating. To ensure that the building’s occupants stay comfortable, RDH ran an overheating analysis for Santa Cruz’s current climate and future climate scenarios. “Santa Cruz has a wonderful climate when looking at current conditions, but what we learned is we really do want conditioned air for future proofing,” says Bloomer. Each studio apartment will be equipped with its own packaged terminal air conditioner (PTAC) unit. A VRF system will be used to condition the ground-floor spaces.
Two Lochinvar heat pump water heaters, installed on the roof, will supply the building’s domestic hot water. The residences are so small that all of the plumbing runs will be in small shafts that project into the corridor.
While DBA’s ambitions are centered on creating buildings that work to mitigate climate change, this project also realizes other DBA priorities. “We want people to notice the building, and for it to bring visibility to housing scarcity and homelessness,” Bloomer points out. Situated at the intersection of two busy roadways, the building will inevitably draw passersby’s attention. Its attractive, harmonious façade hopefully will inspire appreciation and pave the way for additional efforts to address housing shortages.
David Baker Architects’ Sustainability Commitment
"DBA is dedicated to the understanding that the housing crisis and the climate crisis should be addressed as one problem,” explains Katie Ackerly, principal and sustainable design lead at DBA. Toward that goal, DBA developed its own framework to ensure that its projects are guided by critical questions that reflect the most important long-term needs of a community (see Figure 1). In her work guiding DBA’s sustainability progress, Ackerly has been posing the question: Is it time to shift the emphasis of sustainable design away from making incrementally better buildings and toward deconstructing barriers that stand in the way of stronger communities and ecologies? “If we take our story of “co-benefits” seriously,” Ackerly says, “perhaps we could lead with human needs—like resilience, refuge, health, access, and ease—and allow carbon savings to be the inevitable co-benefit, garnering broader acceptance, mobilization, and scalability of climate-positive housing solutions.”
Aiming for consistently improving the firm’s portfolio-based track record, DBA has been tracking actual energy use of those completed projects whose data it can access (see Figure 2), in keeping with the AIA’s 2030 commitment. Edwina Benner Plaza stands out from the crowd both for its close match between actual and modeled energy use and for its substantively lower EUI than the other built projects. It is also one of the first all-electric affordable housing projects in California—which partially explains the match-up. “Edwina Benner Plaza benefited from being part of a California Energy Commission heat pump water heating demonstration project,” explains Ackerly.
Being part of a demonstration project meant that DBA was able to take advantage of technical assistance on the front end—optimizing the design of a novel water heating system, including the plumbing distribution—and monitoring after the project’s construction. Fine tuning the water heating system included programming the water heater’s storage and run times to avoid operating during peak hours when electricity is most expensive, thereby saving money for the client and increasing acceptance of a new technology. The demonstration showed that post-construction commissioning, which is a rare practice in the affordable housing sector, is as valuable, if not more valuable, than new technology. “The commitment to understand what is happening impacts climate adaptation and mitigation in our community-based housing,” Ackerly notes.
One technological change is significantly affecting multifamily housing in California: all-electric central plants. “We are not seeing any new projects now that use gas, and that’s news,” Ackerly points out. Only a year ago a major affordable housing client backed out of an all-electric development, because it was still too new for them, but 2021 has already brought a greater acceptance of the fuel switch to California’s affordable housing market.