OY, those modern window AC units are horrible and really don't cool worth a s**t! I have a cheap Haier 5000 BTU unit down in the shed, which was supposed to be the appropriate size, and it takes FOREVER to cool the place down (but that will change once the dividing wall is up). Heaven forbid you open the door when it's finally the right temperature! I definitely need to find a way to put the Carry-Cool in down there...or get one of those fancy Friedrich units!
We have two central AC units for the house; a large Trane XL1400 (installed 1994-5) which cools the original 1967 section, and a small Rheem unit that cools the pantry, laundry room, and back room (where the Whirlpool and GE Portable reside; added on in 1991 before we moved here). Not sure of the tonnage; will look when I get back tomorrow.