Achieving Net Zero: The Future of School Design

Designing more sustainable buildings is not a new concept. Leveraging the built environment to protect the natural world has been a modern industry focus since the 1970s, originating from the birth of the Green Building Movement. Followed by a second-generation movement in the 1990s and 2000s—in part supported by new LEED rating systems—the built environment has further evolved to incorporate the following considerations: active and embodied carbon reduction, materials transparency, health, wellness, and resiliency towards climate change adaptiveness. Significantly, successful implementations of these strategies have been envisioned through a holistic design approach.

Today’s most urgent facet of green design involves Net Zero Energy (NZE), meaning a building is designed to produce as much energy as it consumes over the course of a year. To see NZE strategies applied in impressive and accomplished ways, we need to look no further than our local Massachusetts school buildings. With K-12 design at the forefront of the growing NZE movement, we should ask ourselves:

What makes a school Net Zero, and how can we use these facilities as teaching tools for both students and the larger community?

Classification & Definitions

The US Department of Energy (DOE) NZE classifications and definitions are used by the majority of the design practice nationwide.

Net Zero Energy Schools Strategy SMMA

A Five-Step Strategy

The biggest challenge in NZE school design is ensuring that the primary function of the building serves and fully supports the student learning experience. This means that designers must be prepared to make decisions along the way that may not provide optimal net zero solutions, balancing sustainability needs with the building’s educational programming. In general, a flexible five-step approach can be taken to achieve these goals while still giving stakeholders choice in what decisions could, and should, be applied. Even if clients were to only achieve the first four steps, their building would be established as a Net Zero Energy Ready (NZER) school and be prepared for future renewable energy additions outlined in the fifth step:

1. Reduce Demand
The building enclosure plays a considerable part in reducing the overall energy consumption of the new school facility. A highly insulated building enclosure, including triple glazing systems, will contribute to reducing the heating and cooling demand. This strategy is a key investment in the facility’s 50-year life cycle.

2. Harvest Site Energy
Harvest ‘free’ energy on site where possible through passive solar and cooling strategies. Classroom designs should optimize abundant daylight harvesting while being mindful of energy performance impacts, locating fenestration where needed. Lighting design can take advantage of available daylight harvesting through reflective interior surfaces. The building orientation can also be optimized to locate occupied spaces to the north and south exposure within the limits of the site’s constraints.

3. Maximize Efficiency
Once the building energy load reductions are implemented, the project design must incorporate efficient lighting, HVAC equipment, and appliances to maximize benefits. Enhanced user-friendly control systems are key to ensure that efficiency measures are fully implemented and monitored during occupancy.  

4. Efficient Operations and Maintenance
The best design concepts will not deliver performance if they are not installed and maintained properly. Building commissioning, training of staff, and ongoing preventative maintenance—combined with monitoring of ongoing performance—can ensure that energy efficiency gains are realized. Building enclosure commissioning and airtight building strategies such as those of the Passive House standard are critical in achieving reduced energy use and demand.

5. Renewable Energy
After maximizing the building’s impact in the steps above, the project design may consider and explore generating energy on site by using renewable energy technologies. This is best achieved after capturing all available building systems and design energy savings. Solar photovoltaic (PV) systems are currently the preferred technology, due to PV’s affordability and feasibility for most clients.

Net Zero Energy Icons
Person Using Energy Regulation App

Net Zero Considerations

Though it may seem like there are many boxes to check off, there are a few key considerations that stakeholders and designers should acknowledge. First and foremost: only build the building that is needed, since area and volume matter directly in energy consumption. This also implies the building should be flexible and expandable to better balance programming with sustainable needs early on in the design process. 

Since the air tightness of the building is critical, investing in full commissioning of the building’s envelope and systems alongside whole building air infiltration testing is also critical. Successful highly efficient enclosures allow for the reduction of equipment size, thereby prompting the use of all-electric HVAC systems. To truly achieve net zero, a building cannot use fossil fuels. 

The final consideration is user behavior and participation in the energy savings goals. Occupants of the building need to be made aware that they are using a net zero building, and each of their actions is important in upholding its status. Daily habits such as turning off lights, closing windows, and using the building after hours can all contribute to the school’s overall functionality: a net zero building will have many controls, and users must make sure they maintain those controls.

Clarifying Perceptions

There are many benefits that come with schools designed for Net Zero. It is critical that designers work with clients to provide clarity and help navigate potential obstacles, spanning cost, energy demand, capacity for harvesting energy, and renewables. For example, while NZE buildings often require higher up-front costs, payback will occur within just a few years, creating significant savings in the long-term. Designing for NZE requires a commitment to a rigorous design process to ensure effective and efficient space usage to reduce energy demand, as well as plan for potential future additions. Part of this process often includes making significant investments in a robust envelope and systems, such as on-site clean energy supplies and evolving technologies to conceive a high-performing, cost-efficient building.

Net Zero Energy Data and Payback

A Revolution in Progress

SMMA’s K-12 Studio has used its integrated approach to successfully implement net zero strategies in the towns of Concord, Lincoln, and Wellesley, MA. These projects have set a standard for sustainability and resiliency, as well as the firm’s school designs moving forward. Net Zero Energy schools are leading by example across the building industry, proving that extreme efficiency is doable and can be used as a building block for what’s to come. 

In the near future, design professionals can anticipate a new Net Zero Energy Stretch Code, supported by multiple community-driven movements and government-mandated goals to reach carbon neutrality by the year 2050. 

Having been involved in several technical advisory groups related to NZE school design as well as current proposed language for the new Stretch Code, SMMA’s Sustainability Group and K-12 Studio will continue to remain ahead of the curve in ensuring that students and their communities benefit from highly efficient and highly sustainable schools.