If one designs a house with thick walls (good R factor) on a slab, you can have a very cool home. My place was designed to be non toxic, warm in winter and cool in summer, all without any air conditioning and minimum heat in the winter.
My next place will incorporate hemp as insulation. It is mold resistant as well as having a decent R factor. It is being used widely in Europe but isn't promoted much here. Lets see...good insulation = low gas or electric bills....ahhhhh that's why ;-)