The Persians had this figured out rather neatly. The dome architecture you see in the middle east had a purpose. As the sun heats the one side, the shaded side remains cool, causing air to circulate, keeping the occupants nicely cooled. Courtyards were constructed to provide a shady spot on a sunny day in an arid and dry land where trees were few. Later, wind catchers, towers with shaped designed to capture wind from any direction and route it under ground, over a pool in a lower chamber and up through the house made what we might call today an evaporative cooler - the first nature powered air conditioning. We typically don't do these things today because we don't need to. Could we? You betcha, and probably more efficiently than 4000 years ago. Could we use less electricity? Yes. Should we force people to (I ask rhetorically, in reference to the EU)? Probably not. Heat waves killed thousands in France several summers back because of mandatory power usage reductions. For some, keeping cool isn't just about comfort, it's about survival.