My hubby designed and built our home. He used RASTRA as shown in this lengthy infomercial. Yes, lengthy infomercial. Still, it's chock full of good information and drives the point home with lots of facts and a not-too-annoying voice dude. :)
They start explaining what Rastra is around 4:10 in part 2. I made a playlist thingy so I hope it works.
If you are interested in this kind of thing, and especially if you are planning to build a new home any time soon...you should look into this for sure. We live in a high desert climate, which means it gets cold every night (even in the summer) and warm during the day. With the home made of Rastra, we have found no need at all for air conditioning (leave the windows/doors open all night to cool off the house in the summer, close 'em when the sun comes up...hardly gain 5 degrees by the time the sun goes down, and that's probably from going in and out the doors). It's like living in a syrofoam cup in terms of insulation, even from noise.
We have a radiant heat system set up under the brick floors, so in the winter we open the place up during the day (and house is angled to optimise the full sun through the windows only in the winter, so that warms things up) and find that having the radiant heat on just between 3-4 AM keeps the subzero temps away during the coldest weeks of the year.
Couple the choice of building material with solar water heating/electricity sources and you've seriously done yourself and the planet a big favor for not much effort, yes?
I guess I'm just posting this FYI in case you didn't know 'bout it. :)