Case Study: Zero Energy

John Lewis Elementary

District of Columbia Public SchoolsWashington, DC

The First Zero Energy, WELL Certified School

In January 2019, Washington, DC, passed one of the most ambitious clean energy laws in the United States. In the interest of modernizing their approach to educational facility design and performance, the District of Columbia Public Schools (DCPS), in conjunction with the Department of General Services (DGS), also began implementing new energy standards for their facilities. These requirements include ambitious energy and carbon reduction rates and enhanced sustainability features in their new and existing building modernization projects.

As DCPS’s first ground-up elementary school, John Lewis Elementary School sets a new bar for sustainable projects within the district. This project aims to become the district’s first triple-certified building, pursuing LEED Platinum, Zero Energy, and WELL Platinum certifications. Named after John Lewis, the Georgian Congressman and civil rights activist, the new 88,588 SF school establishes best practices for educational spaces while pushing the boundaries of improved indoor environmental quality and high-performance design.

The Challenges

  • Design a zero energy school on budget and on schedule
  • Prioritize occupant health and wellness
  • Create a built learning environment that provides access to building operational information within the classroom
  • Pursue ambitious sustainability goals
Created with Sketch.

These high-performance designs require incorporating new philosophies, a higher level of detail, and collaboration between disciplines.... CMTA has helped DCPS achieve unprecedented results while maintaining schedules and budgets and ensuring ease of operations and maintenance. Created with Sketch.

Stephen Kitterman

Project Manager, Department of General Services

The Solutions

Operating at 140 EUI, the original building was a 1960s-era open plan school that presented a challenging educational environment for today’s teachers and students. To assist with paradigm shifts in the approach to DCPS’s building designs, CMTA conducted extensive Zero Energy/Carbon charrettes to bring all building stakeholders into the conversation. By including design and construction, operations, sustainability, educators, dietary, and information/technology stakeholders in the design process, John Lewis was able to maximize both its energy efficiency and occupant health and wellness. The new facility prioritized a modern design that reflected 21st Century Learning environment guidelines, as well as educational and programmatic space needs as specified in DCPS Educational Specifications.

Designed to be highly energy-efficient, the facility produces onsite, carbon-free renewable energy in an amount sufficient to offset the school’s annual energy use via a 650kW photovoltaic array. CMTA designed the facility’s high-performance building systems, including a high-efficiency geothermal HVAC system. The decision was made to use a primary-secondary pumping system that decoupled the building loop from the wellfield, instead of a single variable-speed pumping system. In this setup, one set of variable-speed pumps circulates the primary building heat pump loop. This eliminates the wellfield pressure drop from the primary building loop. When the building loop temperature exceeds the defined controls sequence range, the wellfield pumps pull water from the building loop and send it to the wellfield, providing loop heating or cooling. By implementing an innovative geothermal pumping configuration, the facility’s energy use and utility costs were significantly reduced.

CMTA also provided energy efficient LED lighting design and natural daylighting modeling for integration into the building’s architectural design. The combination of reducing lighting intensity and conducting extensive daylighting studies to maximize natural light resulted in a strategy that drastically slashed interior lighting energy consumption, achieving an overall installed lighting power density of 0.44 W/SF. Additionally, CMTA evaluated the building massing and site’s geographic orientation, performing multiple energy model iterations to optimize the building window-to-wall ratios for each building face. These studies helped maximize daylighting while minimizing the peak HVAC load and associated energy consumption.

To achieve zero energy and zero carbon, the building was provided with a 650 KW solar array on the roof, which was installed by a third party under a power purchase agreement. Having the building operate for a year allowed for system optimization, helping the team right-size the PV array to achieve zero energy as cost-effectively as possible.

Because the project had a significant focus on health and wellness, improving the school’s indoor air quality was a top priority at the outset of design. Since the previous building experienced issues with maintaining and controlling proper ventilation, rather than providing code-minimum ventilation air as required by ASHRAE Standard 62.1-2010, the decision was made to increase ventilation air by 30% in all occupied spaces. To achieve this, the building’s ventilation was provided by a 17,000 CFM dedicated outside air unit with energy recovery, located in the lower-level mechanical room. It provides intake air away from adjacent streets, parking, or other concentrated sources of air pollutants. This unit serves a demand-controlled ventilation system with CO2 sensors in each space. The sensors are set to maintain a maximum of 800 PPM of CO2 in occupied spaces.

While increasing ventilation air resulted in increased energy consumption, the benefits of reducing room CO2 levels—namely, the positive impacts on the indoor environment and improved cognitive learning—were a priority. While the building design was completed before COVID-19, this additional ventilation, along with an upgrade from MERV-13 to MERV-14 filtration throughout, helped to reduce the spread of airborne particles and allowed the building to open to students during the pandemic. To be sure, enhanced air quality testing was performed to confirm that the building met the airborne particulate matter thresholds of PM2.5

SPHERE: An Interactive Learning Dashboard

Designed to serve an underprivileged area of Washington, DC, this project aimed to create a facility to help positively transform the surrounding community. The project team also wanted to design a facility where the building could be used as a teaching tool. The result was an interactive, curriculum-integrated building dashboard for both students and teachers. Far from a typical energy dashboard, this interface incorporates all of the project’s sustainability aspects, highlighting the environmental impact of both the building systems and ways students can help. This dashboard has ten different subject interfaces, each with a tab explaining how students can positively impact the environment in that subject area. By teaching elementary students how to be environmentally conscious, the dashboard cultivates environmental awareness and builds sustainable practices into their lives at a young age.

Additionally, the dashboard contains 360° images of multiple areas of the building, showing what each space looked like during construction compared to the final product. This feature allows students to see where, for example, a geothermal well was drilled directly below the playground. The system is accessible from any computer to be used by students as a learning tool, while also being a valuable addition to teachers’ curriculum.

Click here to see John Lewis Elementary School’s SPHERE dashboard.

The Results

CMTA was proud to partner with DCPS on their first Zero Energy school. After the first year of occupancy, the performance of the new building improved by 40% compared to the original school building's performance. The predicted energy usage for the building was 24 EUI and, after 12 months of data, the building is operating at 22.3 EUI—making John Lewis Elementary School the second-best performing school in the district, after Banneker Academic High School. Additionally, despite the school’s location in a disadvantaged area of Washington, DC, it has seen a 20% increase in enrollment since its opening in August 2021.

The building has also eliminated 1,500 metric tons of CO2 from the community due to its drastic energy reduction and solar energy system. It has recently obtained LEED certification and is currently striving to achieve both WELL certification and the title of Washington D.C.'s first Zero Energy School. As a result, John Lewis Elementary is not only a state-of-the-art, 21st-century learning environment, but it also aims to become a national K-12 leader in sustainability.

John Lewis Energy Consumption vs. Production


John Lewis Elementary's photovoltaic array was strategically sized to overproduce solar energy. This excess renewable energy allows DCPS to meet their zero energy goals by compensating for Banneker High School. Banneker's urban location limited the number of on-site solar panels required to offset 100% of the building's energy use.