I hope I can help - I've had a good look at the various options this summer.
Essentially there are three differenet solutions :
1. Fans (including Dyson prodects) - these have no actual chiller/cooler unit - they work purely by moving air around and cannot actually change the overall temperature of a room.
What they do do, is create a feeling of coolness by blowing air across your skin - which cools you slightly by evaporating any sweat - and we seem to be programmed to feel that a breeze (however warm) is helping with heat.
I have a big problem when these are labelled as 'coolers' (or even worse, 'chillers') - they're not - they just move air aound.
2. Evaporative Air Coolers - these are also fans - but with the addition of a tank of cold water (or ice). The fan blows air across the water/ice and produces a stream of air with some genuine cooling effect - not a lot, but better than a pure fan unit.
These are a decent solution in moderate heat - but seem out of their depth when the going gets really hot. I also worry about the water vapour being emitted in the airstream - it has to condense somewhere ...
3. Real Air Conditioners - containing a proper refrigerating unit.
These are the only solution which genuinely chills the local environment - I've got one and it has reduced my living room temperature from around 29C to 22C on the hottest days this last week.
The downsides are :
a) noise (they are not quiet)
b) cost (they are not cheap)
c) ventilation - they produce a stream of (very) hot air via their exhaust tube - this needs to be directed out of the room - either through a purpose built hole in the wall (expensive) or via a partially opened window screened with curtains or similar (with obvious security issues in some locations).
As far as BTU is concerned, 9,000 BTU will cool a bedroom or small living room, you need 12,000 or 14,000 to cool a decent sized room on a scorching day.
As regards finding one in a hurry - you need to look around - I was assured by all and sundry that "they are sold out everywhere" - but I ordered one for a friend on Thursday and it arrived by 9am on Friday. There's also some nasty 'opportunistic' pricing going one - be careful not to get ripped off too badly.