When summer comes to mind, we almost always focus on picnics, days lounging on the beach, and tasty iced drinks. But hot weather has a gnarly side too. We’re talking about the real dog days of summer, when intense heat and humidity make it impossible to sit comfortably, let alone sleep through the night. 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