When most people hear the words “net zero” they picture solar panels and wind turbines. In reality, one of the first and arguably most important steps to getting to net zero involves optimizing the building envelope and reducing loads. While adding renewable energy is certainly beneficial, it is only one part of the equation. Many net zero buildings start with a reduction of 60-70% compared to the median building by optimizing the envelope and maximizing energy efficiency. By reducing the amount of power generation required to offset the building’s consumption, the required physical footprint and financial cost of the generation system becomes much more feasible for a wider number of building sites and styles.
There are many definitions of net zero ranging from energy use to cost to carbon emissions. For the purpose of this discussion, we will focus on net zero energy, meaning the total amount of energy consumed by the building on an annual basis is roughly equal to the total amount of renewable energy created on the site. While the number of certified net zero projects around the country is still small (43 verified projects with confirmed and measuring energy data across the country according to the New Buildings Institute, the number will continue to rise as cities and states approve policies that push owners to meet these standards. One such example is California’s Title 24, which will require Net Zero residential buildings by 2020 and commercial buildings by 2030.
According to NBI, schools continue to be the largest building category to achieve and target net zero (NBI 2016 List of Zero Net Energy Buildings) with California leading the way in number of net zero buildings overall. Buildings consume approximately 40% of the energy use in the United States, and for school districts, the cost of energy is larger than that of salaries and textbooks. By allowing a school district to spend its money on what matters, the opportunity to reduce or offset these energy costs can have a tremendous impact on education. Additionally, the actual building elements that help to achieve net zero can be used as educational tools, helping to create student innovators who embody the principles of sustainability. These elements can be featured in curriculum and programming that teaches about conservation, energy, health, and collaboration. In Higher Education and Career and Technical Education (CTE) there are linkages between net zero and STEM education and workforce development, as sustainability is increasingly important in a number of career pathways including automotive technology (electric), renewable energy, and landscaping.
Examples of ways that a building can start to achieve the first step of net zero by reducing their loads include:
Orientation/Massing
- Orient the building so that the longer wall exposures faces North and South
- Create a compact design, both in plan and volume with reduced perimeter wall surface area
- Utilize existing trees and natural features to provide shading and windbreaks
Building Envelope
- Increase R-values of walls and roof assembly to provide an efficient building envelope.
- Utilize reflective (white or light-colored) materials for roof and hardscape to reduce cooling loads
- Specify energy-efficient windows with low U-values and Solar Heat Gain Coefficient (SHGC) and reduce the amount of glazing
Daylight and Lighting Reduction
- Configure the building to allow maximum daylight without overheating or creating glare (exterior shading devices, louvres, and light shelves can be used)
- Reduce lighting levels in classrooms and add occupancy sensors and dimmable multi-level switching
- Consider the use of skylights and solar tubes to add natural daylight to interior spaces
Heating/Cooling
- Groups of classrooms should be zoned for Heating and Cooling
- High efficiencyheating and cooling equipment coupled with controls and sensors for conserving and monitoring energy use and energy recovery
Technology and Plug Use Reduction
- Implement wireless computer technology and use Energy Star appliances to reduce plug load and aid in the efficiency and performance of the building.
Operations and Maintenance
- Enable control systems that will monitor and control every electrical device throughout the building
- Provide Occupancy and motion sensors, as well as CO2 monitoring, to maintain an optimum learning environment and reduce the system's power demands.
- Schedule operations to determine areas that require continuous heating, cooling, and lighting at what times of the day, week and year.