Air-conditioning plays an important role in protecting the more vulnerable segments of our population during heat waves. But that doesn’t warrant its lavish deployment throughout society for much of the year. Whether you live in a house on a shady lot or in a third-floor urban apartment, it’s possible to stay comfortable by reviving and updating simple hot-weather strategies that have been cast aside during the age of air-conditioning. And it can be done without costly equipment or home renovations....