Are you considering a mobile air con unit?
We have a Princess one which can be moved from room to room as required.
If so, consider a few things….they are quite heavy but most are fitted with wheels. Getting our upstairs was quite a struggle so it’s now in permanent residence there.
They require a window vent to remove the hot air so you need to position it fairly close to a window. Most come with window kits.
They are noisy, I cannot sleep if ours is working but as it has cooled the room by the time I’m ready to sleep this is ok for me.
We have only used ours for one day this year so far, so cost of electricity isn’t worrying.
To be honest I would get one now while there are are variety to choose from.
OH was having Chemotherapy last year and it was a godsend.