Americans are using less energy — paradoxically, by spending more time indoors, according to a new study in the journal Joule. But researchers point out that keeping more lights on was offset by lifestyle changes that kept people inside instead of roaming around offices and retail stores — like, say, online shopping and working from home. Despite energy consumption worldwide increasing every year, this slight uptick in American hermitage reduced national energy demand by 1.8 percent over a year.