Before we dive in, we realize the obvious solution for cool, calm, and REM-ful sleeping is an air conditioner: These modern gizmos can keep a bedroom at the optimum sleep temperature (roughly between 60 and 70 degrees Fahrenheit), plus provide some nice white noise to boot. But even small window units use up tons of energy and jack up monthly electric bills. So what’s an environmentally responsible, budget-conscious sleeper to do?

Living through a hot summer without AC seems impossible but, hey, our grandparents did it all the time! Turns out, they learned a few things in the process. Here are all those tried-and-true DIY strategies for how to stay cool in summer.