We are considering our 1st project w/Radiant hydronic heating. A few questions to the sagely/&brave:
1.Is floating gypsum fiberglass the best option over existing concrete slab?
2. I understand the earth temp is a constant 55 degrees 8~10Ft down I am placing an artesian grey water/rain gutter collection well in the earth, would it also function to cool the house with radiant if I pumped through coils under the well? Has anyone did this or heard of someone else successfully doing? We are in a low humidity state, I understand you do not want to try this in High humidity.
3. Worst mistakes one could do with radiant? Zinc/metal vs. plastic goose necks on PEX? Companies to use/stay away from?

Thanks Guys!