Five ways we can think differently
#1 Set a clear goal. The first step of a successful ZNE design process is committing to a clear goal, making sure it’s the right goal, and that it’s backed up by a hard commitment. Unfortunately, funding and municipal green building requirements do not tend to be based on EUI targets. Energy metrics are usually based either on a California Title 24 compliance margin or PV offset, neither of which prioritize the right efficiency measures. The goal should include a target EUI and as much PV as the owner can possibly afford, but the goal should also set the groundwork for these next steps.
#2 Evaluate value with cost. The second step is to use design processes and tools that allow the team to evaluate design options on the basis of value—a measure’s ability to enhance the quality of the project—rather than cost and compliance tools by themselves. For example, whole-building, predictive energy modeling, comfort, and life-cycle cost information should out-weigh energy code compliance modeling as a decision tool.
#3 Tie value to social equity. How the team defines “value” should be based on an examination of residents' improved access to opportunity and be mindful of the complicated relationship between social equity and to technological innovation.
Coliseum Place taught us that energy efficiency was actually the least important selection criterion for residential heating, cooling and ventilation systems. Because HVAC system options are limited and bring enormous cost implications, resident health, comfort, resilience and sense of dignity and control, must take precedence. The good news is that you usually don’t have to trade efficiency for human benefits. But the attitude and approach matter. This logic should extend to all areas of design if we recognize all the ways in which the design of our homes and neighborhoods impacts our quality of life. The more that residents have to cope with a home that is isolating, unhealthy, or unsafe—or that becomes unsafe in a disruptive event—the harder it will be to reduce the overall, long-term footprint of housing.
To successfully reduce emissions in the multifamily sector, we should strive to give people of all incomes and abilities equal and fair access to technologies that allow them to adapt and thrive in a changing world. The COVID pandemic has thrown this imbalance of access into high relief. It also highlights a relatively cheap measure that might seem way outside the scope of a ZNE discussion: high-speed internet and virtual mobility. Many low-income households lack access to this essential service, which, pandemic or not, limits the community’s ability to thrive. Buildings can’t solve systemic inequities, but this represents the kind of blindspot we can have when global, greenhouse gas reduction goals define how we think about sustainable housing.
#4 Remember carbon. It’s important to remember that ZNE buildings can have very different carbon reduction profiles because ZNE buildings still use grid electricity, even though they contribute to an overall greener grid. Strategies to load shift and add storage can not only deepen emissions reduction, but also save the owner utility costs and contribute to community resilience.
Embodied emissions, which compete for more of our attention as our carbon-neutral deadline looms closer, is another factor. Coliseum Place taught us that, while we might assume there is not much room to reduce embodied emissions in a typical multifamily building, we can’t forget to have a conversation about our options. For a wood-framed building with one level of concrete, our structural engineer, KPFF, revealed that meeting achievable cement replacement levels would save about 175 metric tons of CO2e, which happened to be the very same reduction our ZNE measures would achieve by 2030, based on a crude, back-of-the-envelope estimation.
#5 Commit to verification. The last and most important change to our process is not new, but puzzlingly new to this sector: verification. This would include basic but thorough examinations of things like envelope framing efficiency, insulation installation and air tightness, efficient hot water distribution, and systems commissioning. The cost of the actual inspection and testing is minor within the context of large systems decisions, and setting the tone influences everything from more effective pre-construction meetings to successful hand-offs with building operators.
If Coliseum Place meets its ambitious EUI goals, it will be because the unconventional, distributed hot water system works optimally, which relies on the building manager’s understanding and compliance with the design intent.