Smart meter data reveals not only when people are home, but what they are doing.

In a landmark Seventh Circuit ruling, the court applied EFF's recent SCOTUS victory to conclude that this data is protected by the Fourth Amendment.
https://www.eff.org/deeplinks/2018/08/win-landmark-seventh-circuit-decision-says-fourth-amendment-applies-smart-meter

Win! Landmark Seventh Circuit Decision Says Fourth Amendment Applies to Smart Meter Data

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...