[Greenbuilding] "Succesful" Open Hydroinic Heating System

[Sacie Lambertson]

Our experience with an radiant heat system with material bought from
Radiantec and installed by ourselves in a three inch concrete floor one inch
below the surface, mirrors almost exactly Ken's in Montana.   We too heat
with wood primarily.  We have a four zone system with inexpensive air
thermostats sat at 60 degrees; the in-floor heat in two of the zones, about
1600 ft sq, and the majority of the main floor, almost never comes on
because the wood heat takes care of those spaces (we have fewer HDD in NE
Kansas than does Ken in Montana).  These rooms, btw have very high ceilings,
large windows and are generally open to each other and we run fans during
the winter  above the stove to distribute the wood heated air more evenly.
We also wear sweaters indoors during the winter.

The radiant heat is run by a propane-fired DHW heater  which had to be
undersized because the vent for it was spec'd at 3 inches.  The vent was
buried in a concrete wall during the framing and before I figured out which
DHW I would buy, so there's nothing that can be done about the need for one
larger.  The person who designated these details also spec'd 3" under floor
insulation for the main floor which according to Wat John also is
insufficient.  I put R 20 under the basement floor but would go higher the
next time and would use foam (rather than Roxul).

If we didn't have the wood stove, we would be SUTC.  Before next winter I
will have built/installed a solar panel system to provide pre-heated water
and this will make all the difference in both the amount of propane we use
each year (around 400 gals for all our hot water needs--we have an tankless
in the bathroom because the DHW could never provide sufficient hot water for
everything) and will also make the radiant system more efficient.

The Radiantec system requires incoming water around 120 degrees, (which we
can't maintain with our current DHW tank so the floors where there is
radiant heat never feel nicely warm).  Five years ago we had no difficulty
dealing with the Radiantec folks, found them courteous and willing to
respond to our many questions.  The pumps and manifold system they sent us
are of good quality as well.

I too would install the PEX closer together (there is a limit to its bending
ability though).

Cheers,  Sacie