alt Hacker NewsI just moved to Portugal and had zero issues installing a portable unit to help me survive the heatwave. For the hinged windows you just grab an installation kit that works with them and you're good to go. The only problem is that the portable AC I got is not a window unit (& it's single-hose), but I wanted to have it before the heatwave started and don't care too much about few percentage points in lost efficiency as long as it keeps me and my pets alive. Total cost was €320 with the installation kit for a 12000BTU unit.
I'm actually surprised you were fine with single-hose. I've never seen a single-hose portable A/C unit that did an adequate job. AIUC, the laws of physics make that rather difficult. In fact I've sometimes seen them actively make things worse. Whereas I have seen dual-hose do an adequate job.
Also note, "survive" is a rather low bar. We're talking about encouraging some of the world's top researchers to move from the US across the ocean. I'm admittedly not in their shoes, but I imagine mere survival isn't their criterion.