What you need to know about net-zero energy buildings
The building industry has a huge impact on our planet – about 30 to 40% of all of the primary energy used worldwide is used in buildings. This energy usage directly correlates to climatic changes and air pollution, as non-renewable energy production continues to dominate the market.
As people gain a better understanding of the impact that the building industry has on our planet, governments at the local, state and national levels are taking the initiative to make buildings more environmentally sustainable, developing codes and standards to lessen the impact. At the forefront, California has a stated goal of requiring all residential buildings to be “net-zero” by 2020, and all commercial buildings will have to meet this same standard by 2030. With these deadlines quickly approaching, building techniques are adapting to meet these goals, and net-zero certified buildings will start to become more and more common. But what exactly does net-zero mean?
According to a paper from the National Renewable Energy Laboratory and the US Department of Energy, “A net zero-energy building (ZEB) is a residential or commercial building with greatly reduced energy needs through efficiency gains such that the balance of energy needs can be supplied with renewable technologies.” Put simply, net-zero energy buildings produce as much energy as they consume. This is no happy accident – precise planning and calculations are required to get a building to this standard. Strict attention must be paid to the way a home or commercial space is constructed to ensure energy consumption is kept to a minimum, and additional systems must be designed to enable the building to also produce energy.
Net-zero building design must be viewed holistically – energy saving systems can be employed everywhere, from early in the structural design process down to the finishing details. At the macroscopic level, design decisions must take into account the huge amount of energy required to regulate the internal temperature of a building. By thinking about this from the beginning of the design process, residential or commercial buildings relative orientation to the sun can be set to maximize or limit the amount of solar light and heat. Elements such as overhangs and well thought-out placement of doors and windows can also greatly contribute to internal temperature maintenance. Additionally, the type of insulation and construction materials used, as well as the quality of glass can all be major factors in regulating temperature and energy use. Additional energy consumers such as appliances and lighting must also be taken into account, and there is a growing market for energy efficient options for both.
Net-zero energy buildings will typically produce renewable energy on-site, usually in the form of wind turbines, solar panels, and/or solar water heaters, which will provide for the building’s energy needs. The energy created onsite can be used for the building’s immediate consumption, and excess power can either be stored for later use or fed back into the electrical grid. Most net-zero homes alternate between a give and take with the electrical grid depending on the efficiency of their on-site renewable energy systems, which can vary with the season. In regards to the net-zero standard, energy consumption versus production is calculated on an annual basis, which takes into account periods of both high production/low consumption and high consumption/low production; the total sum at the end of the year must be zero for a home to truly be “net-zero”.
In addition to being environmentally friendly, net-zero buildings also bring huge cost-savings to the client over time. Knowing all of this, one might wonder why net-zero homes aren’t yet dominating the market. In reality, traditional home building methods weren’t designed to be net-zero and most of the industry has not yet converted to designing and constructing buildings with these standards in mind. Aside from design, it’s difficult to find contractors who are interested in stepping outside of the status quo to learn different, energy-efficient building practices.
BONE Structure’s innovative approach provides significant advantages for the client interested in energy-savings, and is moving toward net-zero homes as the norm, not the exception. BONE Structure homes can actually reduce heating and cooling loads by up to 90% when compared with a traditional house, making net-zero a much more achievable option. The system is also easy for contractors to assemble, removing yet another barrier.
With standards and regulations moving quickly toward requiring all new buildings to be net-zero, the industry is being forced to change and adapt to what will become the new status quo – BONE Structure homes are already raising the bar for what’s possible.
Wikipedia – Zero-energy building
National Institute of Building Sciences, Whole Building Design Guide – Net Zero Energy Buildings
National Renewable Energy Laboratory – Zero Energy Buildings: A Critical Look at the Definition (2007)
United Nations Environment Programme – Buildings and Climate Change (2007)
California Energy Commission