In which country do you live? In Austria you're not allowed to install an split unit AC due to building regulations. You could if you own your own single family house but you need to be very wealthy for that, beyond the average tech worker. Tech worker is blue-colar work here.
I think it's somewhat rare in Germany and Austria, but you don't need to be very wealthy to own a house in France or Belgium for example. And you are allowed to install A/C, in fact heat pumps are very much recommended for new builds, almost mandatory even given the tight energy requirements today and it's becoming common enough to use a reversible one.
(Japan also only has the kind that doesn't do anything. No personal experience elsewhere.)
In my case the entire building I live in has "central A/C". I'm not an expert, but I believe it works by circulating cold water in the pipes and then each apartment has fans in the ceiling that blow cool air. You regulate it by setting the desired temperature in each room using a thermostat. IMO it works very well.
Majority of other buildings with A/C have a more traditional A/C units like in the US that blow air outside.
Like I mentioned in the first paragraph, A/C is non-standard in the country I'm currently in. Some of my friends who don't have A/C use devices similar to humidifiers, but you put ice in them instead of water. They say it's good enough to cool down one room in a an apartment (like a bedroom or an office).
