"Frank Cusack" wrote in message
...
I've been thinking about retrofitting a hydronic radiant floor heating
system into my existing house with hardwood floors everywhere except
the baths. My contractor is experienced with the staple-up systems.

Compared to "infloorboard"
(http://www.warmzone.com/hydronic-radiant-floor-heat.asp), does anyone
have a feel for the efficiency lost by being under the subfloor vs
above it?

That product looks just like WarmBoard. www.warmboard.com

Or is that part about the same ... given that you'd lay
another subfloor on top of the thermal board before putting down
hardwood planks. (yes? or only for tile?) What about over the tiled
rooms?

The other issue is that being on top of the subfloor gives better
insulation from below, right?

I know the retrofit cost is going to be much more than an original
installation cost, but what I'm trying to determine is (ROUGHLY!) how
much more expensive will operating costs be? Slightly more than a
new install, or MUCH more?

thanks
-frank