I recently bought a newer home in Pinal County north of Tucson, Arizona. As I look at my home and at almost all the other homes in the development, it appears that very few have any roof ventilatioin near the top/ridge/peak of the roof. Mine appears to have ventilation only only under the eaves/soffets. I've walked all along the roof, climbed up through the trap door into the area under the roof, and I can find no upper level ventilation. And the roofing material is concrete tiles. I've look closely, without removing any tiles, and cannot see any evidence that there is a vent all along the ridgelines as there is no extra gap under those ridge line tiles.
Yet as I drive around other developments on the north side of Tucson, in Pima County, most newer houses have some kind of upper level ventilation. Now I'm new to Arizona and warm climates. I come from the cold climate of Seattle, where very few houses had any air conditioning, and your furnace would be turned on from September 15th to June 1st. While the ceiling of my 2001 built house is well insulated, it just seems to me that not having any upper ventilation, the roof is trapping a lot of hot air which in turn would cause the house to be hotter than it should, and therefore making it more difficult to cool down.
Is there something wrong in my thinking?