RMH for 3000sq ft

Six yrs ago I started my project. It took a while as I did most myself from the driveway to the building. Over the yrs the rmh always caught my attention. I’m at a point to where I want to try and build one. I’ve only done simple research but ready to get a plan on building one. I do like the batch box idea due to the size. I have estimated 37k cubic ft, good insulation but none under the concrete. I’m located in TN and winters aren’t that bad. Last yr heating the building with a torpedo for a 8hr day took around 1-1 1/2 gallons per day. The coldest week it never got below 50 during the night at knee level. Please share your info and links that I can read upon so I can have a intelligent conversation.

Hi Andy;  Welcome to Permies!  And Welcome to the wonderful world of rocket science!
Here is a link to Peter Bergs batchbox site)  http://batchrocket.eu/en/
Here is a link to Matt walkers site) https://walkerstoves.com/index.html

Matt builds riserless cores and sells detailed plans on building them

Peter is the batchbox innovator.  His site has multiple different  designs  with detailed measurements on building.

Let us know what your thinking and please send photo's when you start building!

Thank you Thomas for the links. I’ve found Peter’s page but not the other. I’m leaning towards a barrel type. Just not sure it will be big enough for the size I need to heat. I have the ability to weld and fabricate with metal but I’ve never worked with blocks and mortar.  I think that will be the hard part for me.

You would be amazed how much heat is radiated from the barrel from burning just a small bundle of "kindling." It really surprised me the first time I felt it.

Jordan you are probably correct as I’ve never been around one. I have been around a double barrel type heater.  I’m curious as how a thicker bell would do. Maybe a 1/8 or 3/8 Think bell/ barrel and how long it would take to heat up and store it longer. Most that I find on barrels are for small houses. I do have a couple old propane tanks laying around. I found Peter Berg YouTube page and like his double shoe box that he did with the barrels.

My only reply will be, big batch.

https://permies.com/t/44806/Cobbling-workshop-heater-cooktop-oven  

Heating 635m3 iirc. Going sometimes down to -20c°

Satamax Antone wrote:My only reply will be, big batch.

https://permies.com/t/44806/Cobbling-workshop-heater-cooktop-oven  

Heating 635m3 iirc. Going sometimes down to -20c°

Thanks for the link. That is a big boy. How was the steaks?  I like the idea of cooking on a stove.

Andy Bhill wrote:

Satamax Antone wrote:My only reply will be, big batch.

https://permies.com/t/44806/Cobbling-workshop-heater-cooktop-oven  

Heating 635m3 iirc. Going sometimes down to -20c°

Thanks for the link. That is a big boy. How was the steaks?  I like the idea of cooking on a stove.

It's hard to learn to cook on it. Controlling the temps, or even knowing the temps is complicated. But i get better at it. The oven was a lovely addition. The top of the firebox plate, is perfect for stews, and sizing steaks. Thought, that stinks the whole place.


The things i would do differently now, is less, metallic surface, for less fast heat. Because it overheats the place, and more mass. I think leaving just the firebox and oven door, plus the cooking plate is sufficient for my fast heat needs. Mind you, when it's real cold, it might not be. It's hard to find a happy medium.

Satamax Antone wrote:

Andy Bhill wrote:

Satamax Antone wrote:My only reply will be, big batch.

https://permies.com/t/44806/Cobbling-workshop-heater-cooktop-oven  

Heating 635m3 iirc. Going sometimes down to -20c°

Thanks for the link. That is a big boy. How was the steaks?  I like the idea of cooking on a stove.

It's hard to learn to cook on it. Controlling the temps, or even knowing the temps is complicated. But i get better at it. The oven was a lovely addition. The top of the firebox plate, is perfect for stews, and sizing steaks. Thought, that stinks the whole place.


The things i would do differently now, is less, metallic surface, for less fast heat. Because it overheats the place, and more mass. I think leaving just the firebox and oven door, plus the cooking plate is sufficient for my fast heat needs. Mind you, when it's real cold, it might not be. It's hard to find a happy medium.

How big of area are you heating? As I search it’s hard to get all the info on people builds. Knowing you go down to -20c helps me. My winters average around freezing at nights. Couple yrs ago was the coldest in 20yrs. Had about 7-9 days below freezing dipping down to -10c at nights. Shop never go below 11c last winter. I have to covert as I’m use to Fahrenheit here.

Hi Andy. My shop is 113M², and i heat the flat above with the rocket too. I have 54m² approximately.

That's about 1200 and 600 sqft. Floors of the flat are wooden, and insulated with 14cm wood fibers.

Barely any insulation on the hollow brick walls, besides the strawbales i've piled up against these. 12cm of cork panels in the roof. Nowhere near enough for here. That's a workshop i bought from a pothead, with no concrete pad on the floor, nor doors. It's been a chore to work with the hollow bricks, since i got it.

I get cold inside, when it reaches -18, -20. I have then to redo a burn in the morning, and three loads of the firebox at night. With -20, in the morning around 8 o clock, it's down to 17c° It wouldn't go two days, then; without burning.

I have R6 US value, approximately in the brick walls. May be R7, at the flat's height, with the wood siding. And little insulation behind. R17 us, in the roof. No insulated concrete pad.

When the actual norm calls for R34 US, in the walls, and R45 US in the roof. For my location and altitude. Which means i have nowhere near enough.
http://www.myonlinediary.com/index.php/Insulation/US-EuropeanRValueConvertionTables

HTH.

Thanks Satamax for the info. I decided to just build what I’ve been thinking about. So I pull the tank out and put in on rollers so I can start cutting the extra junk off and remove the paint. I figured I’d post pics as I build it and people could give advice or straight up tell me I’m wrong.

This evening I made a base and added a way to level it once tank is welded to it. Thought this would look good.

Thought I’d update this thread. I’m unable to build this and use it due to insurance company. Even though the local office that I deal with did take the time to learn about this style of heater, he likes the idea and understands how it works. He actually wants one now. We spent several days discussing it and it basically came down to the underwriters didn’t want to insure it because of ul approved. I do understand their point and they understand mine. I have to have insurance!!  Want to thank everyone for your time and help.

Sadly Andy you are not the only one that had to cancel a RMH build due to insurance.
Nice your agent was interested enough to learn about them!  Too bad he could not convince the underwriters they are safe.
Don't give up hope. The more folks that learn about these amazing stoves the better.
Rome wasn't built in a day and stodgy old insurance underwriters retire and young progressive ones take over.
Laws were meant to be changed as needs change... lets hope this law changes soon!  

I'm wondering if this is one of those instances when calling it a masonry heater might have eased any regulatory concerns.  RMH's are, at their most basic level, masonry wood burning appliances. I don't think we need to rewrite the building codes, we just need to make them work in our favor, and that means applying the appropriate language to achieve the desired outcome.

Thomas Tipton wrote:I'm wondering if this is one of those instances when calling it a masonry heater might have eased any regulatory concerns.  RMH's are, at their most basic level.  Masonry wood burning appliances. I don't think we need to rewrite the building codes, we just need to make them work in our favor, and that means applying the appropriate language to achieve the desired outcome.

Yep, and going batch too. J tubes scare insurers.

Andy Bhill wrote:Jordan you are probably correct as I’ve never been around one. I have been around a double barrel type heater.  I’m curious as how a thicker bell would do. Maybe a 1/8 or 3/8 Think bell/ barrel and how long it would take to heat up and store it longer. Most that I find on barrels are for small houses. I do have a couple old propane tanks laying around. I found Peter Berg YouTube page and like his double shoe box that he did with the barrels.

My barrel is 12mm thick Andy and it has somewhat of a lag time before it radiates, but once up to temperature, it holds it for hours.