Paint / Coat roof to reflect sun's energy?

Unfortunately modernistic building practices do not lend themselves to the convection principles found in nature. They come from a time when a lot of homes had to be built in a hurry and affordably to keep up with a population explosion. In my region there are still homes being lived in that never had insulation in the walls or ceiling or floors. Single pane windows and an open crawl space foundation. Knob and tube wiring. One, although not lived in, still has its original 120 volt 30 amp utilities service intact.
 Several characteristics of these homes are high ceilings and tall windows close to the floor, as well as plaster and lathe interior wall finish. Some with Horse hair in the plaster. Large Oak trees all around, front porches and sheet metal roofs. Its a common site here in the Carolinas.

I can only imagine that they were very hot in the Summer and very cold in the Winter but that it made for a very interesting character, for those that lived in them back then.

Now, in contrast to that old style there is Earth sheltered homes. If only they had been the established way instead of the stick built homes.
http://www.daviscaves.com/index.shtml
http://www.thenaturalhome.com/
And then there is...
http://www.limsi.fr/Individu/mpons/solaradsor.htm

Mid-Missouri.  We have all four seasons here.  Sometimes in the same day.

I don't think they're much of an advantage in the winter.  As part of our off-grid home plan, we'll be switching from electric home heat to wood burning stove.  We'll keep the electric elements in the water heater and HVAC only as a backup.  We can take the home heat off the electrical load, but we can't do that with the A/C in the summer.  Evaporative cooling doesn't work in my area, since Missouri summers tend to be more humid than just hot.

I did find that the local Lowes has this reflective roof coating.  I picked up a 1 gal. bucket, and applied it to the roof.  At 83°F outside temp, and 125°F shingle temp, the coating on the roof was only 85°F !!  From 125 to 85 is a pretty huge difference, so I'm going to coat more of the south-facing roof.  Before I do, I'll take temp readings from the ceiling (gotta love my IR tire pyrometer) of all the rooms.  The idea would be that for the thermostat set at, say 80°, the ceilings, especially in rooms further from the HVAC blower, should be cooler after application.

I'll know by week's end.  It looks like tomorrow thru thursday should be rain-free, so I'm going to run to the hardware store and pick up more of the roof coating today!