Sir82, I find your replies to my query to be quite derogatory, as well as uninformed. If you consider the theories applied in selecting construction materials and the principle practices of heating and cooling you will note:
a. hot air rises and therefore the greater heat loss will be through the roof. Hence, heat gain also due to the large surface area of the roof during the cooling season.
b. During mild weather the "windows" could be opened to allow "free cooling".
I tend to think from your replies that crosses may intimidate you.