Energy and Indoor Air Quality Benchmarking of the NIST Net-Zero Energy Residential Test Facility (NZERTF)
Tania Ullah, Dustin G. Poppendieck, William M. Healy, Arthur H. Fanney, Kevin Y. Teichman
The National Institute of Standards and Technology (NIST) designed and built a residence that could generate, through the use of renewable energy systems, the amount of energy required by a virtual family of four over one year. The Net-Zero Energy Residential Test Facility (NZERTF) utilizes enhanced air sealing techniques, high levels of thermal insulation, and high- efficiency equipment to meet the comfort levels and functions of the virtual occupants while lowering energy consumption. Adequate ventilation and reduced indoor contaminant sources were also key design features to support occupant health and comfort. The purpose of this paper is to assess how current and new approaches to benchmarking apply to high-performance homes. This study compares the annual energy use intensity (EUI) of the NZERTF (33.8 kWh/m2 or 10.7 kBtu/ft2) to the EUIs of existing single-family detached homes in the Mixed-Humid climate zone and the entire United States. The study presents the NZERTF's Home Energy Rating System (HERS) index (-6 with on-site power generation, 31 without), Home Energy Yardstick score (10), and the HUD Energy Benchmark Tool score (97). In contrast, indoor air quality (IAQ) benchmarking is challenging and not yet standardized. Concentrations of formaldehyde in the unoccupied NZERTF are typically above long-term non-carcinogenic relative exposure limits, but in the lowest 10th percentile compared to recent surveys of new, occupied homes. Concentrations of other volatile organic compounds (VOCs) in the NZERTF tend to be higher than these other homes, but below concentrations resulting in health concerns (except for acetaldehyde). A truly high-performance residence must exceed both energy and IAQ benchmarks, as well as those related to thermal comfort, water consumption, and others. This work highlights the challenge in finding appropriate benchmarks to which a high-performance home should be compared.
Proceedings of the 2016 ACEEE Summer Study on Energy Efficiency in Buildings
August 21-26, 2016
Pacific Grove, CA
2016 ACEEE Summer Study on Energy Efficiency in Buildings