Conventional wisdom says that if you put solar panels on your roof in the Northern Hemisphere, you should point them within 30 degrees of true south to generate the most energy in the course of a year. But a new study by Pecan Street Research Institute, an Austin, Texas-based research and development organization, suggests that most people may do better at covering their own electrical use and reducing stress on utility grids during summertime peak demand periods if they aim the panels westward instead. (See related quiz: What You Don’t Know About Solar Power.”)

Though the study has not been released publicly, Pecan Street provided a copy to National Geographic News. It analyzed 50 homes in the Austin area,