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Radiant floor heating from a wood stove ?

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Posted by CALS on August 30, 2006, 1:20 am

Hello all,

I am proud to say that I didnt turn on my oil burning furnace on once
last winter !  We only heated our entire house with our wood stove
along with a few blowers and fans to move the air around.  If you know
the winters in Quebec, Canada at all, you know that can be a challange.
One of the problems is that some rooms are too far away and get very

My question is this, I would like to harvest some of the radiant heat
from the stove from a small grill on top of or beside the stove.  This
adjustable grill (1/4") copper tubing will be hooked up to a pump that
will circulate the warmer liquid through 60 feet of crawl space to heat
the floorboards of our bedroom through radiant floor heating pipes in
between the floor joists.

Do you think this would work ?


Chelsea, Quebec

Posted by DJ on August 30, 2006, 3:15 pm

CALS wrote:

Hey Marc. atleast SOMEBODY is happy with all the rain we've been
getting ;-).

Yeah, it will with provisos. As per the grill, though, bigger is
better, and hotter is better. A recirc loop right inside the woodstove
box would be better, and stainless steel more reliable than copper.
Heat transfer can be pretty low for a situation like that.
You're thinking something like an automotive transmission cooler or
such in the space between the heatshield and the stove?
Might want, also, to consider hydronic baseboards instead of radiant
flooring to do the job of heating. Wood floors and radiant flooring
don't work well together, especially when the tubes are, I think, going
to be put on the unheated side of the floor? Be perhaps a good idea to
insulate the crap out of the underside of the floor instead and put in
a radiant baseboard in the room.

Another thing some folks do is use the woodstove to heat the hot water
heater, and the hot water heater to run the hydronics (with a heat
exchanger and a pump) in the distant rooms.
Done a few like that over the years.


Posted by Bruce in Alaska on August 30, 2006, 6:16 pm

In my cabin we use a 6" OD, 6 turn, 5/8" Copper Tube Coil mounted inside
the first section of the 6" Galvinized Fluepipe above the woodstove.
I bring the coil pipes out the back of the fluepipe and use
thermosyphan techniques to circulate the hot whater to a 50 Gal Holding
Tank.  Then, I have a secondary 30 turn, 3/4" Copper Coil inside the
Holding Tank that feeds PEX Tubing under the cabin floor, but above
4" of Hard Pink Insulation, and 6" of Fiberglass Batts, insulating the
cabin floor. The secondary loop has a small 12 Vdc diaphram pump that
is switched with a Air Temp Thermastat. Keeps the cabin toasty, even
long after the fire has burned down, and works well down to -15F.....

Bruce in alaska
add a <2> before @

Posted by sitkasue on March 27, 2012, 8:30 pm
 responding to
sitkasue wrote:
Bruce  in Alaska wrote:

Hi Bruce I was wondering if you wouldn't mind telling me a little bit more
your in floor heating system?  I am in the process of designing a cabin
thinking about in floor heating but cannot go electric as electricity is
$.75/kwh where I am at. We were thinking of having the coils in the
behind the wood stove but not sure weather this would produce enough heat
to make
a difference especially since we are at the waters edge and built on
pilings with
only 2"foam insulation underneath the floor. The guy in this equation
(owner/builder) wants to "keep it simple" and is not real excited about
tanks, expansion tanks, pumps etc. Mind you not that he is incapable
because he
is very but he just doesn't want to do anything that will be too elaborate
(anything that is a pain in the ass) Any input from others who have first
knowledge, pros and cons would be greatly appreciated. ~ Vic in AK

Posted by Ecnerwal on March 28, 2012, 2:53 pm
Sometimes complexity is needed to keep things simple.
The storage tank can accept heat when the stove puts it out, and
distribute it when needed. An expansion tank is needed on any
closed-loop system. The only way you could hope to avoid pumps would be
to move the fire downstairs (evidently into a boat at your site as
described - or make it a two-story cabin.) Even then thermosyphoning to
a whole floor is tricky to engineer and may involve very large (and
expensive) pipes.

As for getting the heat in the first place, the greater the temperature
difference, the smaller the heat exchanger can be for the same output.
Getting useful heat from "warm walls" is a lot harder than from a hot

Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

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