This. - Leaky ("breathable") home constructions vs. air-tight tolerances required to code now. - Region-specific cooling and design practices which aided in t

This. - Leaky ("breathable") home constructions vs. air-tight tolerances required to code now. - Region-specific cooling and design practices which aided in the dead of the summer (or winter!) - More geographically-minded decisions: Mature, treed lots for shade (double points for deciduous trees in winter which let the sun radiate through), more E/W facing vs N/S. - Architecture: Smaller, closed off rooms (shut the door to trap the heat/cold), breezeways, enclosed porches all seemed a lot more popular then vs. now when keeping cool (or warm, in the rooms' case) was a priority. Of course, mileage will vary, but this is something interesting I've found comparing the house I grew up in (built 1952), my first home (1986), and our recent build (2018) which are all within <5 miles of each other. FWIW, if the HVAC doesn't run all day at the new home, it's a noticeable "stagnant air" when you get home.