Guys, I've got two questions on hydronic radiant. 1. When using a gas boiler/IDHW (Prestige Excellance) will that unit make continuious hot water like a tankless when the tank is depleted? 2.How is engineered wood flooring over slab with radiant, I've heard of problems that can develope? Building a ICF home with spray foam roof and blow-in to raise to R50+. Is it worth the money to use radiant in the garage if using for the rest of the slab?

Hey Fred;

the excellence is like an on demand, with a limit of roughly 3GPM of hot water output in most areas.

engineered wood varies in quality. good quality wood is no problem.

if you want to continuously heat the garage, it's hard to beat adding some pipe to concrete you're going to pour and insulate anyway. if not, slab radiant may not be the way to go (but piping it is still cheap and nice "just in case").

be aware superinsulated homes don't get toasty feet. you get comfort, but 'invisibly', so don't expect a "happy hotfoot".. floor temps are relative to the heat load and floor area servicing the heat load.

hope that helps!

Thanks Rob, for your opinion! People in my area aren't to familiar with these systems and the cost is pretty steep. Just wasn't sure I could justify the cost and also have AC to which I'll need.
I know it's a real comfortable heat and energy efficient, but on the other hand I didn't want to over extend myself!

Thanks again
Fred

Any one know what is the best flooring to have with the radiant heating.? We are putting in the radiant heating now and flooring next.

We are putting in radiant heat in our new home. Someone suggested to me that it's better to the tubing above the slab and then encase it 2'' of floor leveler. His reasoning is there is less condensation created when the styrafoam insulation is warmed by the heated slab. Also if there is any leaks it is a much easier fix than having to bust up the slab. I have also heard about the fin system where the tubes run through the joists. How good is that system? Any comments would be appreciated.

if you are pouring concrete anyway, it almost never makes sense to do radiant via any method other than putting tubing in the concrete.