I've mentioned this a few times before in other posts, when I built our home I didn't install central heating and no AC, all we do is just when things start cooling down toward evening is to open a lot of windows and a sliding glass door in the bedroom, turn on a few small fans and a couple of ceiling fans (only 9.5 watts each on low). At about 8 in the morning we close all the windows and even on a 104 degree day it's never gotten more than 80 inside. It would probably be cooler if I would have built all of the roof as a cold roof, but just having the North roof a cold roof has made a tremendous difference, when I built the addition to the South side I couldn't afford putting a cold roof on, it's also twice the surface area, at least I've got plenty of attic insulation there and I'm sure that helps, as it was I think I was also running up against the rainy season and was pressed to get the roof done, ASAP. Thinking of those old houses, many were built with tall windows that could be opened at the top as well as the bottom, I remember that the elementary and high schools I attended had those kind of windows and no AC, still got hot but it could have been worse without constant air flowing into the rooms because of those kinds of windows.