The companies say that you get something like an R32 wall, and that will make the basement nice and cozy when we have the radiant heat in the concrete floor down there!!
There are lots of folks building their houses completely out of the ICFs in areas of the country where it's hot most of the time, and you want the most efficiency out of the A/C. That would be the just the ticket for your Mom in AZ!
That's what we're hoping. Please keep us posted on how your installation goes- especially the DIY portion. We'll be looking for sweat-equity opportunities like setting the forms ourselves to keep costs low.