We retrofitted our 110 year old home with hydronic radiant heat and now I need to insulate the basement ceiling to reduce heat moving from the main floor slab to the unconditioned basement. I am considering spray foam insulation and roxul. The spray foam will cost me $1600 and is the ideal product however I am sure I could save some money by using roxul. The basement ceiling will remain open and I don't know anything about roxul and whether or not it will disperse fibres into the basement and if those fibres are harmful. Alternatively I could use fiberglass but I am even more uneasy about the glass fibres spoiling indoor air quality.

The spray foam would need to be covered for fire reasons. You might also look into spray cellulose - it can stick to ceilings with limited thickness. Or gypsum board over dense pack cellulose.

With cold weather fast approaching I had to make a decision. The main issue is that with all the mechanical and electrical and water/heating runs on the basement ceiling there is no way to cover the insulation. I found a fellow who did an exhaustive review of the science and found that Roxul (made from basalt rock and slag) is safe so I am insulating with R24 Roxul.