By Reilly Loveland
[Editor’s note: Reilly Loveland will be a presenter at a half-day Pre-Summit workshop on Zero Net Energy school retrofits on November 27, at the 2017 Green California Schools and Community Colleges Summit in Pasadena, California. This session is open to all attendees at no cost. Details here.]
While still nascent, the Zero Net Energy (ZNE) market is growing rapidly—nearly doubling every year in the numbers of verified and emerging projects. Education is a leading sector with 88 projects across the U.S. that are achieving ZNE or have a stated goal of ZNE performance, according to New Buildings Institute (NBI), a nonprofit organization that tracks the ZNE market. Of those buildings, nearly 60% represent K-12 schools. (NBI, 2016). Studies show that classrooms with sustainable attributes contribute to improved knowledge gain by providing a more comfortable and healthier environment for students and teachers (Heschong Mahone, 1999; (Bakó-Biró, et al., 2007). Specifically, sustainable schools designed with advanced energy features provide first-hand insight into how a burgeoning market for ZNE buildings is taking shape. This market calls for highly efficient buildings that can meet all their energy needs with on-site renewable resources. It is a segment of green building that has emerged in the last few years through advancements in technology and growing pressure to address climate impacts from buildings, which now account for 40% of carbon emissions in the United States.
In addition to the well-documented financial benefits delivered by energy efficiency (EPA, 2015), the ZNE classroom offers a healthier and more productive learning environment. Resources to improve student learning are continually being developed and evaluated, but what if school buildings themselves became a tool to enhance student learning? ZNE schools become a living laboratory for students to better understand the nexus of technology, innovation, and the environment, bringing home the impact that our built environment can have on natural spaces. Students are exposed to a real-world application that spans math, science, and engineering curricula and the interconnectivity aspects of 21st century smart buildings. These smart facilities interweave the natural environment with technology to provide such benefits as better indoor air quality (Joseph et al., 2016) and acoustics which contribute directly to enhanced student and teacher performance (Nelson & Soli, 2000). Fewer sick days for teachers and students means a better education for our future generation.
Effects on Health in Zero Net Energy Schools
Over the last two decades, school community stakeholders such as school board members, school occupants and designers have become increasingly aware of the correlation between the quality of the school environment and the effects on health. With students spending approximately 1,000 hours per year in school buildings (Hull & Newport, 2011), transforming classrooms into healthy and productive spaces is of the utmost importance, especially when the long-term and short-term health of students and staff is at risk (Lawrence Berkeley Labs, 2016). Studies demonstrate that students in classrooms that are well-ventilated and daylit are more comfortable and less prone to illness (see sidebar: Health and Education in Green Schools Fast Facts). Turns out that ZNE schools feature both the passive ventilation systems such as natural ventilation, dedicated outdoor air systems (DOAS) and demand-control ventilation along with daylighting strategies that enable these benefits.
Indoor Air Quality and HVAC Systems
There are several key concerns when it comes to indoor air quality and health in schools, but most important is the direct relationship between carbon dioxide (CO2) levels and human cognition and brain function. A study completed by Joseph G. Allen, et al. from Harvard showed that occupants in ventilated spaces with low CO2 and low volatile organic compounds had improved scores in crisis response, information usage and strategy ranging from 100 to 300% (Allen et al., 2016). Alternatively, excess CO2 can slow student cognitive function so they are less attentive with memory and concentration levels going down significantly (Bakó-Biró, et al., 2007). Additionally, studies have shown that students in poorly ventilated spaces have 50 to 70% more respiratory illnesses.
Traditional HVAC systems that help reduce CO2 concentrations can be noisy. Teachers struggling to maintain student attention sometimes preferred to suffer in a hot, cold, or stuffy room rather than teach over the noise. “The HVAC [unit] is so loud, I heat the classroom before school starts, but then I just leave it off when I’m teaching,” a teacher from the Oakland Unified School District told Will Gorrissen with Stok (Karolides, 2017).
Overriding the HVAC system obviously challenges the fresh air exchange. Silent, low-energy passive design options such as wind ventilation, stack ventilation or night flushing coupled with efficient mechanical ventilation can be a good solution to both the indoor air quality and noise issues of traditional HVAC systems. They provide clean, fresh air at a stable and comfortable temperature while reducing CO2 levels indoors and maximizing the free benefit of natural air movement.
Daylighting and Energy Efficiency
The quality of lighting in the classroom also has an enormous impact on student health. Up until the 1970s, daylighting in schools was widely utilized, but post-1970s trends favored highly conditioned spaces that drove smaller window-to-wall ratios to limit energy loss and heat gain. The unfortunate result of this design strategy was that schools constructed during this era were designed with significantly less access to daylight. Today, we know that daylighting designs, which allow natural sunlight to permeate deep into interior spaces, reduce the need for electric lighting and provide health benefits resulting from views and connection to nature, reduced glare, and access to natural light (Nicklas & Bailey, 1995)
Several case studies on student health and daylighting bear out these positive results. In Johnson County, North Carolina, students exposed to daylight or full spectrum lighting, which mimics daylight via energy efficient lighting installations, attended school 3.2 to 3.8 more days per year. These lighting features also produced better moods in students and had significantly lower noise levels (Healthy Schools Network, Inc., 2012). In Wake County, North Carolina, middle school students exposed to lighting systems focused on harnessing the benefits of natural light were more attentive and overall exhibited lower levels of hyperactivity in the classroom (Healthy Schools Network, Inc., 2012). Another study noted that children exposed to only moderate light levels (a combination of daylight and electric light) earlier in the day exhibited increased body mass, whereas children who received the largest amount of light exposure such as a mixture of daylight and efficient electric light were slimmer and had a healthier body mass index (Pattinson, et al., 2016).
Health and Education in Green Schools Fast Facts
- Studies have shown a 50-70% increase of respiratory illness in spaces with low ventilation rates (Lawrence Berkeley Labs, 2016).
- Occupants have faster and more accurate responses to a cognitive function test at high ventilation rates Bakó-Biró et al., 2007).
- Students exposed to daylight attended school 3.2 to 3.8 more days per year (Healthy Schools Network, Inc., 2012).
- Students in daylit schools progress 20-26% faster on test scores (Heschong Mahone, 1999
Effects on Education in Zero Net Energy Schools
In addition to the health benefits, qualities of ZNE learning spaces can offer students a leg up on academic success. The next generation of schools will house our future governmental, business, and environmental leaders and warrant investments in classrooms designed to encourage student performance at the highest standards. Students themselves understand the positive outcomes of hands-on opportunities that give them practical experience. This can be delivered through the “bricks and mortar” of the school itself. Using the building as a tool for energy literacy, supported by curriculum integration, can deliver the societal changes necessary to be responsive to energy goals for 2030 and beyond.
Educational Outcomes from Building Design
Imagine the type of school our students need to achieve the best educational outcomes. A daylit, passively ventilated, comfortable, and collaborative space. Students are working with access to natural areas outside and have the ability to mold their space to fit their educational needs. The windows in the room are large, insulated, and operable with shading options when needed, but oriented so that glare is minimized and daylight is available to students all day. In our ideal classroom, the space is also passively ventilated so that traditional HVAC noise is nonexistent and the air is a constant temperature, reducing distractions and optimizing focus and learning outcomes.
An early study conducted by Heschong Mahone Group and NBI revealed that students in daylit environments showed a 20-26% improvement on test scores compared to traditionally lit environments (Heschong Mahone Group, 1999). Specifically, students with access to skylights that provided diffused light showed19-20% more improvement than those without a skylight; students in classrooms with operable windows progressed 7-8% faster than those without operable windows; and students with access to the most daylighting performed 7-18% better in math and reading than those without.
The quality of the aural environment also has a serious impact on student’s cognitive performance, concentration, and achievement (Nelson & Soli, 2000). It has been widely reported that noisy HVAC systems comprised of compressors and fans running off and on all day provide a constant stream of distracting mechanical noise of varying sound levels in the classroom. A study conducted by Ana Maria Jaramillo demonstrates that students exposed to the noisiest HVAC systems underperformed on achievement tests relative to those utilizing quieter systems (Jaramillo, 2013). Brains that are actively developing, such as those of young students, are not able to recognize speech to help fill in gaps of missed information until they are in their teens. Background noise can inhibit students from fully comprehending lessons to draw future connections and build on their existing knowledge (Crandell & Smaldino, 2000).
Zero Net Energy Schools as a Living Lab
While the non-energy benefits of ZNE schools are compelling, perhaps the most valuable aspect of these projects is the savings in operating cost and utility bills. Given that the educational sector consumes over 2,000 trillion BTUs (CBECS, 2012) of energy of all types per year, savings across a district could mean hundreds of thousands of dollars that go back into the classroom. For example, Boulder Valley School District (BVSD) in Colorado has an ambitious master plan to have its portfolio of more than 50 school buildings be ZNE by 2050. Preliminary modeling shows that just three of BVSD’s buildings have an achievable energy savings of 67% equating to $58,000 saved per year.
The energy savings and clean energy aspects of low-energy schools have inspired some educators and facilities staff to band together and make advanced energy schools a teaching tool. At Fayette County Schools in Kentucky, students, educators and staff become part of teams that perform waste and energy audits and study their research to form actionable recommendations about potential improvements. Schools are also encouraged to save via the “Go Green. Earn Green!” program where schools saving 5% or more energy in a monthly billing cycle will earn 10% of their savings to be applied towards student-driven sustainability improvement project.
Many ZNE schools are controlled by energy management systems that offer real-time feedback on energy performance of rooftop solar panels and energy use across the building. The ongoing data stream provides students with opportunities to crunch the numbers, apply statistical principles, and problem-solve around unexpected results proving that as technology becomes a more integral part of daily life, building technology provides a natural extension for learning. Students learn where energy comes from, how it is generated, the societal and environmental effects of different fuel choices, and the cost impacts on their daily lives in school and at home.
In Shelby County, Tennessee, where 75% of the energy supply comes from coal, a curriculum module was designed so that students could understand what is going on behind the scenes when they turn the lights on and off, and that every choice they make affects “A-Z” from the source to delivery. “From a personal perspective, students learn best when they have a hands-on model,” says Tracy Leaks, Shelby County Schools Green Schools Project Leader. “It’s one thing to read out of a textbook, but it’s an entirely different level of autonomy when they are visualizing where energy comes from when they turn this light switch off. They realize when they turn this light switch off not only are they saving energy, but they are turning off a circuit!” (T. Leaks, personal communication, May 26, 2017).
Building on this new understanding, Shelby County students identified opportunities for saving money by cutting energy waste and doing their part to reduce greenhouse gases. These student “green teams” routinely check for indoor air quality and energy efficiency improvements around their school. They perform air quality checks by measuring and documenting light levels, temperature of classrooms, and humidity levels.
Through this kind of experiential learning, students become engaged occupants who can support the necessary behavioral changes that allow a ZNE school to meet performance targets. Students learn that their actions, even small changes, can have a large, cumulative impact on results. Technology advancements in thermostats, lighting controls, and monitoring systems offer immediate feedback on impacts of different actions—both positive and negative. Either way, teachers and students inhabiting the classroom are given a sense of control and ability to monitor their own energy use.
Vanessa Carter, Environmental Literacy Content Specialist at the San Francisco Unified School District likes to see students digging in on building operations. “Not to overlook the benefits of technology, but I fear the ease with which we all survive each day without much awareness of the systems that support us and how they work. For students to get a window into how the building uses energy leads to numerous educational opportunities and even career development.” (V. Carter, personal communication, May 25, 2017).
ZNE schools are the future. They provide a level of design, technology integration, and measurement and monitoring beyond what the average building affords. Teachers can leverage these tools to drive experiential learning about passive design, on-site energy generation and storage, cutting-edge technology, community integration, and the natural environment. They provide a learning lab far more effective than any textbook.
Most importantly, using a school and its daily operations as a tangible, hands-on learning tool increases student performance and lesson retention in comparison to traditional lecturing practices (Freeman et al, 2013). Students are given the opportunity to grasp 21st century skills like teamwork, research gathering, time management, information synthesizing, independence, and utilizing the high-tech tools of today. This greater understanding and deeper knowledge of concepts like science, math, and technology in relation to their surroundings give students the confidence to take leadership roles in their schools as advocates for environmental sustainability and their own learning needs.
Zero Net Energy Building Technologies in Schools
ZNE schools are low energy buildings coupled with renewables that provide a ready generation resource. A school achieves zero net energy when the energy produced meets or exceeds the energy used over the course of a year. It’s important to note that while ZNE is the end game for building sustainably, it is a process and can take time to accomplish. When designing for ZNE, implement your energy efficiency measures first, engage and educate occupants, and then install renewables later if it is too cost restrictive in the original design-build process
The most integral part of ZNE is the design which brings to the table all disciplines and key stakeholders that inform a building. The approach brings everyone involved in the project from the design phase to construction to the day-to-day operations and occupants to set goals and collaborate on ideas and solutions right from the start. Frequently, typical processes fail to recognize that buildings are large, complex and dynamic where all systems work together as a whole entity. The integrated design approach fully integrates systems to achieve maximum efficiency. Some examples of these systems and technologies are:
- Building Orientation, Window to Wall Ratio, and Glazing Location/Optimization
- Highly Efficient Thermal Envelope
- Ventilation: Natural, Dedicated Outdoor Air Systems, Demand Control Ventilation
- Conditioning: Ground Source, Radiant, Chilled Beams
- Controls Integration
- Daylighting Access and Controls
- Solar and Glare Control – Shading
- Energy Recovery Systems
- Plug Load Reductions
- Energy Management Systems
- Building Dashboard
To learn more about ZNE schools, check out New Buildings Institute’s website for more information and resources like fact sheets, case studies, presentations, and messaging guides: http://newbuildings.org/hubs/zero-net-energy/
Reilly Loveland (firstname.lastname@example.org) supports the project management team at the New Buildings Institute (NBI) on various K-12 schools related projects including Prop 39 Zero Net Energy School Retrofit work in California. She designs and develops NBI workshops, public engagement materials, and other technical and market transformation resources. Prior to joining NBI, Reilly worked for the Integrated Design Lab and Washington Green Schools doing research and energy analysis, developing and maintaining databases, and designing energy focused K-12 curriculum. Reilly has a background in finance and lending as a result of her work as a sustainability consultant for a Real Estate Investment Trust in Los Angeles, California where she was the USGBC-LA Green Schools Co-Chair for Los Angeles County. She has a B.S. in Geophysics, Environmental Science, and Resource Management from the University of Washington; holds accreditations, certifications and licenses in Real Estate, ArcGIS, and LEED; and is a Green Classroom Professional.
Allen, J. G., MacNaughton, P., Satish, U., Santanam, S., Vallarino, J., & Spengler, J. D. (2016, June 1). Associations of Cognitive Function Scores with Carbon Dioxide, Ventilation, and Volatile Organic Compound Exposures in Office Workers: A Controlled Exposure Study of Green and Conventional Office Environments. Retrieved May 20, 2017, from https://ehp.niehs.nih.gov/15-10037/
Apte, M. G. et al. (2003, June). Simultaneous Energy Savings and IEQ Improvements in RelocatableClassrooms. Retrieved May 25, 2017, from https://indoor.lbl.gov/publications/simultaneous-energy-savings-and-ieq
Bakó-Biró, Zs., Kochhar, N., Clements-Croome, D.J., Awbi, H.B. & Williams, M. (2007, January). Ventilation Rates in Schools and Learning Performance. Retrieved May 20, 2017, from https://www.researchgate.net/publication/242261403_Ventilation_Rates_in_Schools_and_Learning_Performanc
Commercial Buildings Energy Consumption Survey (CBECS) (2016, May). Total energy consumption bymajor fuel, 2012. Retrieved May 31, 2017, from https://www.eia.gov/consumption/commercial/data/2012/c&e/cfm/c1.php
Crandell, C. C., & Smaldino, J. J. (2000, October 01). Classroom Acoustics for Children With Normal Hearing and With Hearing Impairment. Retrieved May 23, 2017, from http://lshss.pubs.asha.org/article.aspx?articleid=1780236
Environmental Protection Agency (EPA) (2015). Energy Efficiency Programs in K-12 Schools: A Guide to Developing and Implenting Greenhouse Gas Reduction Programs. Retrieved July 20, 2017, from https://www.epa.gov/sites/production/files/2015-08/documents/k-12_guide.pdf
Freeman, S., Eddya, S. L., McDonough, M., Smith, M. K., Okoroafor, N., Jordt, H., & Wenderoth, M. (2013, October 8). Active learning increases student performance in science, engineering, and mathematics. Retrieved May 31, 2017, from http://www.pnas.org/content/111/23/8410.ful
Healthy Schools Network, Inc. Daylighting. (2012). Retrieved May 25, 2017, from http://www.healthyschools.org/downloads/Daylighting.pdf
Heshong Mahone Group. (1999, August 20). Daylighting in Schools: An Investigation into the Relationship Between Daylighting and Human Performance. Retrieved May 20, 2017, from http://h-m-g.com/downloads/Daylighting/schoolc.pdf
Hull, J., & Newport, M. (2011, December). Time in school: How does the U.S. compare? Retrieved May 20, 2017, from http://www.centerforpubliceducation.org/Main-Menu/Organizing-a-school/Time-in-school-How-does-the-US-compar
Jaramillo, A. M. (2013, March 22). The Link Between HVAC Type and Student Achievement. Retrieved May 23, 2017, from https://vtechworks.lib.vt.edu/bitstream/handle/10919/50565/Jaramillo_AM_D_2013.pdf?sequence=1
Karolides, A. (2017, May 25). Zero Net Energy Schools. Lecture presented at A Technical Deep Dive into ZNE School Retrofits in The Environmental Innovation Center, San Jose, CA.
Nelson, P. B., & Soli, S. (2000, October 01). Acoustical Barriers to Learning: Children at Risk in Every Classroom. Retrieved May 23, 2017, from http://lshss.pubs.asha.org/article.aspx?articleid=1780235
New Buildings Institute. (2016, October 13). 2016 List of Zero Net Energy Buildings. Retrieved May 30, 2017, from http://newbuildings.org/resource/2016-list-of-zne-buildings/
Nicklas, M. H., & Bailey, G. B. (1995, December 31). Student Performance in Daylit Schools. Retrieved May 20, 2017, from http://www.ncef.org/content/student-performance-daylit-schools
Pattinson, C. L., Allan, A. C., Staton, S. L., Thorpe, K. J., & Smith, S. S. (2016, January 6). Environmental Light Exposure Is Associated with Increased Body Mass in Children. Retrieved May 23, 2017, from http://journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0143578
 These numbers reflect the current amount of ZNE Verified Buildings as verified by New Buildings Institute and are higher than those in the Getting to Zero list from 2016. An updated version will be published fall of 2017.