As much as we rarely get these days, I still have my portable aircon units that I wheel out for a few days each year, they cost me £160 each about 12 years ago, and I can keep two rooms nice and chilly.. last night the bedroom was 28 degrees, after 30 mins that was down to a reasonable 21 of crisp cool air..
I've also got some proper split airconditioners I bought back from Spain when they where selling them off for 99 Euros, I keep thinking of getting those fitted but to be honest the decent portable ones do a good job and then wheel them back in the cupboard when not in use..