slab on grade, single story, new build 1700 square foot home- just picked up the plans from my architect and he says I don’t need insulation under the slab only at the edges?!?

I’m aiming for a net zero energy home, building with R30 ICF blocks and european tilt-turn windows- curious what the group thinks my slab insulation should be?

considering using Glavel or foam, just not sure what R-value I should be aiming for- and don’t want to disqualify my house right off the get go with the slab.

Thanks!