That R70 number does ring a bell. Also, I was standing in the unfinished second floor talking to him and it was very hot outside but the room was quite comfortable. He wasn't running any air, it was just well insulated. And it was quite in there, a large truck drove by and I barely heard it.
He was saying he would use a whole house fan but had an a/c unit he could use for the few really hot weeks in the summer.
It was a really neat home, on a small lot, with a great view. Small lot was why he was building up.