"Jon Grimm" wrote in message
...
I am curious about hydronic radiant heat, and wonder if anybody here has
experience using a lesser quality tubing than PEX.

I won't get into judging better or worse, but I have installed, and am using
a hydronic heating system in my shop, and have already installed a portion
of an identical system in the new house we're building. The major
difference is the type of tubing used. My system is a Heatway variety, a
branch of Watts, who bought them out about three years ago. Heatway uses
a proprietary rubber hose made specifically for hydronic heating, by a very
well known American manufacturer. It has an oxygen barrier plus lamp black
in its composition to improve heat transfer, and consists of three
reinforced layers. It is available in various diameters, so pretty much
any size installation can be addressed.

Like Leigh's report, my system holds beautifully. It has been in service
for over three years heating our 2,600 foot shop and we've not had one drop
of solution (clear water) leak. I'm sold on the system, and have no
argument with the rubber hose they use. It is more expensive, although I
do not claim it is either better or worse. My one and only worry with the
PEX tubing would have been for an instance whereby the concrete floor
cracked and shifted. I feel rubber would be slightly more forgiving of that
scenario, but perhaps it wouldn't be. I installed 1/2" (#4) rebar @ 18"
centers both ways, so even if it cracks, it shouldn't lose alignment, so in
my case there is precious little about which to be concerned so far. The
concrete has cracked only where it was scored, and there has been absolutely
no settling of the 6-1/4" thick concrete.

I would suggest to you, or anyone that is interested in installing hydronic
heating, that there be no experimenting with tubing. Only accepted
materials with a good track record should be installed. Regardless of
whether they are poured in concrete or stapled up, a leak could prove
disastrous. I understand that the biggest problems they had with early
systems was the inability to make water tight connections. That has been
well addressed now and the systems, when installed properly, are very
successful.

Hope this helps~

Harold