Living in a "temperate zone" often means cold winters and hot summers, with short interludes of perfect temperatures in between. While that breaks up the monotony, the power bills at the extremes can be terrifying. Nolan Gray is studying for a graduate degree in city and regional planning from Rutgers. Inspired by an interlude living in Guatemala City, he looked around the world for places where you can live comfortably without using a heating system or an air conditioning system. He found 13 cities that fill the bill, and quite a few other places where you don't need much temperature control. That resulted in an interactive map where you can select a place to live where the temperature doesn't fluctuate much from comfortable. Find those 13 cities and look around the map at Medium.
That said, there are times when I could use AC, but you can always just head down to the beach.