Are you looking to keep the place at 68F with solar-assist or are you simply looking for freeze control or...???
For a solar-heated ANYTHING, building to a high R-value is important if you want your solar fraction to be well into double-digit percentages. R10 mininum XPS under the slab, R20 at the slab-edges, R20 min clear-wall R-values (that's R-20 even after thermal bridging of framing elements are accounted for). Air-tightness & controlled ventilation counts too.
But if you're talking about an open shed with a radiant floor with solar snowmelt/freeze control it's a whole other issue. Can you be more specific? |