CREJ

30 / BUILDING DIALOGUE / September 2019 ELEMENTS Net Zero Net Zero Energy: Making a Positive Impact T wenty years ago, many people were not familiar with the term “sustainability.” Some had heard the word but didn’t know the real meaning. Now we know. “Sus- tainability” is a catch-all phrase that speaks to many facets of the work we must do to combat climate change. “Net zero energy” is a new phrase that many people have heard but may not know what it means. Synonyms are “carbon neutral” or “zero energy building.” Net zero energy is a term that we will know well in the coming years. A simple definition of NZE is: “a building which offsets all energy used in the building with renewable ener- gy created on site, calculated on an annual basis.” Buildings use energy. A lot of energy. Buildings use 40% of the primary energy in the U.S. (primary energy is the raw energy used to create electricity, gasoline or other refined energies that we use ev- ery day), and buildings use 80% of the electricity running through our power grid. As architects, de- velopers, builders, business owners and building users, we have the potential to make a real differ- ence in our nation’s energy usage. By creating NZE buildings ,we can have a positive impact. Creating a NZE building is no small task, but through careful design we have the ability to do that today. Almost any building can be Net Zero Energy, and the cost need not exceed the cost of a typical well-constructed building. How to Create a NZE Building These four steps to design a NZE building can be implemented by any knowledgeable design pro- fessional: 1. Use nature. Design the building to use the sun for passive solar heating and daylighting, mini- mize unwanted solar heat gain during the sum- mer, utilize cooling breezes or nighttime flushes, or other natural design techniques that will help the building perform better. 2. Seal the envelope. The “envelope” is the exteri- or walls and roof of the building. By using high levels of insulation and airtight construction, we can minimize the amount of heating and cooling that is lost through this envelope. That saves a lot of energy and reduces the size of mechanical sys- tems. 3. Use efficient all-electric systems. Most of our buildings use natural gas to heat the building or to heat the water used in the building, but there are a variety of very efficient electric systems that are now available to replace those gas systems. Ef- ficient systems will have a coefficient of perfor- mance of 3 or greater (a COP of 3+ means for every unit of electricity used, three units of hot air or hot water are created). We know we can’t produce natural gas on site, but we can produce electricity, therefore a true NZE building must be an all-elec- tric building. 4. Photovoltaics create electricity on site. Photovol- taic panels create electricity from the sun. When we perform these first three steps well, then we can install PV panels on the building to offset the electricity used in the building. If we don’t have a well-insulated, well-sealed, all-electric building that uses the sun and breezes (those all-important first three steps), then we will never be able to in- stall enough PV to offset the electric usage. Peter J. Ewers, AIA, LEED AP BD+Cn Ewers Architecture PC Joel Kivett A net zero energy residence in the foothills of the Rocky Mountains, designed by Ewers Architecture.