The Seventh Circuit just handed down a landmark opinion, ruling 3-0 that the Fourth Amendment protects energy-consumption data collected by smart meters. Smart meters collect energy usage data at high frequencies—typically every 5, 15, or 30 minutes—and therefore know exactly how much electricity is being used, and when, in any given household. The court recognized that data from these devices reveals intimate details about what's going on inside the home that would otherwise be unavailable to the government without a physical search. The court held that residents have a reasonable expectation of privacy in this data and that the government's access of it constitutes a "search."
This case, Naperville Smart Meter Awareness v. City of Naperville, is the first case addressing whether the Fourth Amendment protects smart meter data. Courts have in the past held that the Fourth Amendment does not protect monthly energy usage readings from traditional, analog energy meters, the predecessors to smart meters.