You're getting the gist of my point. I bring up being in a place hotter than Boston to point out that it's high temperatures that strain the value of a window u

You're getting the gist of my point. I bring up being in a place hotter than Boston to point out that it's high temperatures that strain the value of a window unit, not mild or cold temperatures. A lot of Europeans defined by the context of this post are dealing with rapidly rising temperatures. Combine their generally unaccomodating architecture (very prevalent on the quite ancient Mediterranean coast) and rising temperatures put them in a place that window units do little to solve. That's not to say they're uniformly useless, but that certain groups of people are going to gain little from adopting them.