Systems are described as the next frontier for energy efficiency policy, offering the potential to unlock huge energy savings in equipment-based energy-using systems. In this summary we highlight some of the key findings from 4E’s investigations over several years. This includes estimates of savings potential, options for overcoming some of hurdles to regulation and the identification of system types most amenable to regulation. This work is ongoing and 4E welcomes interaction with others interested in investigating this topic more widely. Download the report from our Publications page – Progressing Energy Efficiency Policies for Systems.