"with a hard vacuum between"!!! LOL!!
Now that's what I'm talkin bout!! 
Since I've 'discovered' Solar screens, I'm pretty sure that a good design idea
for this area is, loads of south facing multi-pane windows for winter heating.
With full solar screens, that cut down solar gain by 80% to 90% during the summertime.
And of course a modern mini-split as the main heating system.
Maybe a gas backup for the super cold days..
Without that solar gain, that Zero house would have been a lot cooler after
a week without heat..