As a side note, it's nearly impossible to buy a dual-hose portable AC in the UK and Europe. For whatever reason, the market has converged on inefficient single-hose portable ACs.

People on here will literally write walls of text over the most mundane nonsense.

Get a free standing unit like this: https://i.imgur.com/giewYeK.png

Shove the plastic tube outlet out of a window. End of installation. You're welcome.

Seriously why is this so difficult and what is this learned helplessness? You would rather be miserable than do literally anything?

you don't need that on balcony, most of the apartments have balcony, stupid excuse, same applies for historical buildings with balcony

If a tree falls in a forest and no one is around to hear it, does it make a sound?

If there is a balcony and you install it there, so nobody can see it from the street, is there an AC installed? Can you even use your balcony the way you want and place there big cardboard box if you need? Same thing. Facade is a one thing, balcony is something completely different, if you can't even use it, what's the point in having it.

Where? The only mobile split unit i can find is 899

Realistically a decent mini-split that won't break in a year and won't make too much noise starts at ~€600-800 + €400 installation in a low-labor-cost country (Latvia), in high-labor-cost countries such as Germany the installation bit might be twice-thrice as expensive.

It's not the money. In many places you need to go through permitting to get it and they do not want to give it to you. Often you also need a signed approval from every person in the building.

Sounds good! It was a waste to begin with. They can handle first-class.

My multisplit system costs <€60 a month to run even during the hottest months, which is way below heating costs during winter. And that's keeping entire apartment at constant 22ºC - people with higher "comfort temperature" can keep the bill significantly lower.

unless they also come w/ rooftop solar?

new mini splits are way more efficient than older systems as well.

insulation in older homes/buildings might be an issue though

Ironically- while often having solar on the roof.

I got a 7000BTU one last week. One of cheapest I could find (I suspect some price gouging given the timing of my purchase). Very small, works in one small room. It was about £400. None of my family or friends have £400 sitting around that they can spend on a whim to save them a few weeks of suffering. A huge number of people live paycheque to paycheque and have no savings or credit lines available to them.