Zero-Energy Buildings Attainable Across Climates, Researchers Say
Energy use index (EUI) is a good indicator of whether a building is zero-energy capable; a maximum EUI of 35 kBtu/ft2 is recommended. The average for office buildings is based on the most recent Commercial Building End-Use Consumption Survey (CBECS).
By Paula Melton
Net-zero-energy commercial buildings are becoming more mainstream and don’t need to cost more, according to a recent report from the New Buildings Institute (NBI). The report compiles a list of 21 verified zero-energy buildings (ZEBs) and 78 zero-energy-capable buildings (ZECs) in the U.S. and Canada in order to discover what features the buildings share and to examine incremental costs.
“When we looked at the measures for constructing these buildings, there was nothing outside what’s available today,” said Stacey Hobart, communications director at NBI. Although they all use highly efficient equipment, there was no “super advanced technology that is not commonly known or used,” she told
EBN. And while the buildings tend to be small and some are unusual types, such as visitor centers and field houses, the number of larger net-zero schools and office buildings is growing.
While the buildings studied operate in many climates, they shared a few common strategies, particularly natural daylighting (85%), high-efficiency lighting (68%), and high-performance envelopes with increased insulation and well-insulated glazing (50%). Details on the cost premium associated with ZEBs and ZECs were harder to pin down because the set of buildings was so small, Hobart said, but it ranged from 0% to 10% compared with buildings of the same size and type in the same climate.
“The efficiency levels needed for ZEBs are readily obtainable, with current technology and at reasonable incremental costs, for many common building types,” the report concludes. The study recommends better practical guidance, better data collection, and better central repositories for that data to make benchmarking easier. NBI hopes to continue publishing regular updates about net-zero-energy buildings as they become more common. The researchers are asking building owners and design teams to help them discover the 100th building by sending their information through the NBI website, www.newbuildings.org.
The project team sought to create a healthy home for a family of four to live in as independently and with as little environmental impact as possible, situated on a sustainable homestead producing energy and food. The owners did not want to build on prime agricultural land, but chose a rural site that had good solar and/or wind resources, with space for animals and gardens. With the intention to use only as much energy as could be produced onsite, a building strategy was developed that reduced the amount of energy needed to run the household and used an appropriate site-specific renewable energy solution. This has helped the occupants cultivate a strong sense of stewardship of the local environment and given them the tools to help others do the same.