I have only one room with A/C, and it's the study, not the BR. The worst of HHH here on Long Island is mid-afternoon, so the study becomes the "Refuge" for a few hours then--a desk to work at and a sofa to sit or lie (nap, actually) on.
A powerful whole-house exhaust fan cools things down a bit after sunset, and the BR is sleepable with a window fan, and nights that are really uncomfortable are rare. One benefit of the Northeast over the South is that although we get weather like the South on and off in the summer, we also get bursts of frontal passage Canadian air from time to time that are blissfully pleasant spells, even in the midst of August.
However, although I keep the Refuge A/C set at 73 or 74, if it were not for the horrendous cost of electricity, I'd prefer to keep the room at about 62, which is what I keep the house at all winter, and find perfectly comfortable. It's easy to get warm--just add some clothes; it's difficult beyond a certain point to get cool--I'm sitting in the un-A/C'd computer room, not the study, and although I'm wearing shoes and sox, the rest of my clothing is a thin film of sweat--and while today's high is only predicted to be about 87, we're not there yet!
