The Future of Weather Files for Building Performance Simulation in New York State

Weather data has a wide range of applications in the built environment such as the analysis of energy efficiency measures, life cycle cost, and emissions. For the past 50 years, building simulation efforts have typically relied on typical meteorological year (TMY) or reference year data (Crawley, 2015), but recently some applications have switched to alternate weather files, such as actual meteorological year (AMY), extreme meteorological year (XMY), and future typical meteorological year (FTMY) data. This study explored the impact of switching from existing TMY datasets to more recent or future-looking datasets through a literature review, stakeholder interviews, weather file analysis, and a modeling exercise. The study summarized the current state of weather file availability and usage, data variation among available formats, impacts on projected energy use and peak demand, challenges to switching to new formats, and the implications for program and code development protocols for a state agency.