RMH Minimum Footprint

Hi All,

I am closing on a new property Monday & am interested building a RMH. The living space is currently heated only by electric baseboard heaters (ouch!). The owners had a small wood burning stove which they took out because they got tired of feeding it. It is still there in the garage, and the stovepipe chimney is also still in place. I intend to hook it back up for the short term, but would really love to replace it with a RMH. The only concern I have is that I won't have a lot of space to construct one. So... the question is what would be the minimum effective footprint needed for a RMH. The living space is approximately 1280 sqft, two story, 640 downstairs, 640 up.

I'll have tons of bio mass to burn. The property is 8.4 acres, and there are very large piles of downed tree limbs all over. The thought of being able to heat the place on all this wood that needs to be removed anyway because it is a fire hazard is very appealing.

Thanks

Kevin, with a rocket firebox, either J tube or Batch, and a bell, you shouldn't take much space. Something like 10 to 15 sqft is totaly doable.

Kevin Millar : At the present time These Commercial models with bells instead of a cob thermal mass have the smallest size foot print and weight!

THis should give you an idea of what is out there . //// Link below :


http://www.dragonheaters.com/rocket-masonry-heater-products/


For a 1st time build it really is go commercial or build a more D.I.Y. Friendly 6'' J-Bend Rocket with Thermal mass bench ! For the Crafts ! Big AL

Hi Kevin

It seems that you are the first beneficiary of a post I intended to do about a minimal RMH. I'm not ready yet to do that post, however, I will give you some details and will let you know about the full description that I'll do later, fully illustrated with pictures.

I used firebricks (21.5 x 10.8 x 3 cm). The construction lasted about 3 weeks - 1 month, because it was my first rmh and I took my time. There are about 2 weeks I'm testing it, so take my word for this.

Feeding 10.8 x 5 cm, burn tunnel 10.8 x 7.8 cm, riser diameter 12 cm (+1 cm fire resistant mortar and an enclosing can diameter 14 cm, just to hold the mortar) and 32-33 cm of height (including the 3 cm of the brick, FYI), distance between end of riser-bottom of barrel is 5 cm, barrel diameter 23 cm, flue 12 cm (could have been lower, but I opted this way.

Footprint: 70 x 30 cm (including the elbow).

The result is this beautiful monster (not finished yet as regards aesthetics, but working like a charm).

Blendi

I don't know why the final and most important picture did not attach, it's my first post and maybe I did something wrong. however, here it is

allen lumley wrote:Kevin Millar : At the present time These Commercial models with bells instead of a cob thermal mass have the smallest size foot print and weight!

THis should give you an idea of what is out there . //// Link below :


http://www.dragonheaters.com/rocket-masonry-heater-products/


For a 1st time build it really is go commercial or build a more D.I.Y. Friendly 6'' J-Bend Rocket with Thermal mass bench ! For the Crafts ! Big AL

Allan, have you tried any of the dragonheater stuff?

Yes, Sending you a P.M.

Blendi - That's a nice looking little stove. We will be very interested in hearing as you continue testing how well it works. With so little mass, it can't give heat for long after the fire is out... how long does the masonry stay warm? What is your space like: size, windows, insulation, your climate (how cold has it been while you tested?)

There are a few details to mention. You say the burn tunnel is 10.8 x 7.8 cm - it has been found that if the burn tunnel is not square in section, that it works better if it is higher than wide.

A feed tube 10.8 x 5 cm is much smaller than the burn tunnel, and it is recommended that the burn tunnel be the smallest section if all is not uniform. The small opening will make it tricky to scoop ashes out of the burn tunnel - how is this working for you? How often do you need to add sticks to the fire?

The riser with only 1 cm of mortar on the outside sounds like it is not well insulated, while part of the performance is caused by a well-insulated riser that keeps the heat in. What material is the 12 cm diameter riser, and what kind of mortar is on it?

Lastly, even such a small stove should be more effective if it has enough mass to absorb most of the heat generated. How hot is the stovepipe as it leaves the mass?

Kevin
Can I hijack your thread? And use this one to post everything on my small RMH? After all, it's in your interest (I'm sounding like the government )
Blendi

The footprint on my first rocket is only a 15" diameter circle lol. But it only has about 350-400 lbs of mass.

Is there a hijack link to your stove , bendi? I am interested in more about it also

No, I asked the one who created the thread to post my stuff there, but he didn't answer so I didn't follow through. When I have time will do a new thread, or post it here.

Blendi