Globally, households are shrinking – more and more people are living alone. In 2016, almost two thirds of all households in the EU were composed of one or two people, with shrinking households also prevalent around the world. As countries move up the human development index, households are expected to continue to shrink. As households have got smaller, homes are getting larger. This increases energy and resource use, domestic waste and greenhouse gases. After all, most households have similar appliances like stoves and fridges, and cooled or heated spaces, regardless of how many people live there. There is also a tendency to share less within apartment buildings compared to previous decades. In Sweden, where once sharing a laundry room was the default, now more than 80% of newly built apartments have their own washing machine. Smaller households simply don’t benefit from the sharing potential of larger households. So it’s no wonder that shrinking household size is emerging as a fundamental challenge to reducing resource consumption and mitigating climate change.