Well we do not have an attic, just the ceiling which is pitched like the roof. The ceiling , just like the walls are plaster. I reckon that the ceiling is plaster, and airspace and then the roof deck and then the tar paper and shingles. house was built in 40's so doubt if there is insulation in the roof deck space . rafters are 2x6. About 3 years ago we had the outside wooded siding removed and replaced with composite siding. When old siding was removed our contractor noticed that there was zero insulation, which was not uncommon in the 40's . Did not really have insulation much back then. Anyway we had contarctor blow in wall insulation. inside walls were plaster, then air space, then wood boards then siding over that. Of course with new siding they also put on house wrap which they did not have back in the 40's. I am thinking that the oly way would be to tear the whole roof off and try and add insulation to the space of the roof deck. Probably not worth it. I am 58 and as soon as daughter graduates from college in about 3 years we plan to sell home and move into apartment. we want to travel more and not have to mess with home maintenance. oh we do aslo have a 5,000 BTU window ac as well in a bedroom upstairs as well, but we only run that on days that are 100 degrees which is only maybe 5 or so days per year. Our central unit does fine keeping main floor and basement cool, but on days when it above ohh 95 plus the upstairs just does not stay cool without the window units to assist. for the most part here in lincoln NE that is about mid June to mid to late july. This week is lower 90's and my wife kept the window units off. I am guess that many homes that do not have an attic probably tend to get quite warm, now way to really insulate the roof deck. Yes I cannot really tell how much cooler the reflective shingles are making. compared to last summer maybe a couple of degrees, but not really enough to make much difference, but certainly cooler than dark shingles. though here in Nebraska when it snows tha dark shingles have a slight advantage. Our central AC and furnace was sized correctly for our house by the furnace AC company, but on real hot days 95 to 100 plus it cannot make up for that non insulated roof deck with no attic for air ventilation.Our windows are insulated Pella installed about 10 years ago and never ice up or leak. most of the heat radiates from the roof I think. Our walls are now insulate with blow in, not sure how much that helped. Our electric during summer is about $130 during the hottest time and probably be about $110 -120 for aug and then will drop to probably $70.00 during fall winter and spring.