building a rmh for a wood frame house

New here to these forums. I have a few newbie questions about building a rmh for my house.

My two biggest concerns are the weight and the heat of it.

I have an old wood frame house and i need to make this as light as possible, im not sure how much one of these could weigh when finished.

My other concern is the heat it will produce on the back wall it sits next to. I like the idea of the wood frame. In fact, i can't think of a better way to build it in a house like mine. but i would like to know how hot the wood would get.

This isn't something i could make too big either, not only due to weight but just taking up such space. so i may have to have less thermal mass

also what would i use as the thermal mass? i dont know if there is much clay in my ground around here, and concrete from what i understand isnt great to use, and it weighs so much!

and what is the "chimney" part in the combustion chamber made out of if you arent using fire bricks?


Im also not against paying for rmh plans, but I need to make sure i can even build one before i buy anything. If i had alot of money to spend, i would get a new furnace first,lol.
Heck, i would gladly just donate as well..

thanks for the help in advance!

here's what i was thinking... i know there would be very little thermal mass. but i only plan to use it as a supplemental heat source, not a sole heat source. so i would just be needing the additional heat during the day

do you think this would work? does someone already make something like this i could buy that you know of (i lack a welder)

Details of your particular house would be very relevant here. You own the building, have full control of it, right? Also the presence of code enforcement in your community is relevant and any plans you may have for selling the house in the medium/long term.

Thermal mass is.... MASS. <g> It's going to weigh in proportion to its effectiveness. The first obvious thought is to build a good foundation up from the ground (your basement?) to hold whatever is going to really heavy and hot. Structural wood floors can be built to carry a lot of weight but considering you want thermal mass also, building up with masonry probably makes more sense. I believe there may be pics on site here of somebody who built their foundation up from the basement. "Search" is your friend.

The immediate area around the "fire box" needs to be fire proof.

To get the most from your heat you want it to radiate from the center of the space, not from against one wall - that wall gets toasted and the heat then proceeds to the outer yonder. But I know, sometimes a central location is not practical.

Just the most basic thoughts. Those that actually know will have to advance your answer from here on.

Cheers

Rufus

Rufus Laggren wrote:Details of your particular house would be very relevant here. You own the building, have full control of it, right? Also the presence of code enforcement in your community is relevant and any plans you may have for selling the house in the medium/long term.

Thermal mass is.... MASS. <g> It's going to weigh in proportion to its effectiveness. The first obvious thought is to build a good foundation up from the ground (your basement?) to hold whatever is going to really heavy and hot. Structural wood floors can be built to carry a lot of weight but considering you want thermal mass also, building up with masonry probably makes more sense. I believe there may be pics on site here of somebody who built their foundation up from the basement. "Search" is your friend.

The immediate area around the "fire box" needs to be fire proof.

To get the most from your heat you want it to radiate from the center of the space, not from against one wall - that wall gets toasted and the heat then proceeds to the outer yonder. But I know, sometimes a central location is not practical.

Just the most basic thoughts. Those that actually know will have to advance your answer from here on.

Cheers

Rufus

yes, i do own the house and I do plan on selling it someday, that may be a while though. i would love to buy some land and move off the grid. but that may take a while. The way my house is set up, it seems it would not be feasible to have it in the center of the room. maybe i'll eventually take a few pics of my place to show what im working with

Joshua

I am really not especially RMH knowledgeable, although I have been working in the trades for 30 years. As I understand the RMH concept it's a method to burn a small fire _very_ hot for a short time and capture 95%+ of the heat into thermal mass before it leaves the building. W/out the thermal mass you're not going to capture the heat even a relatively small very hot fire gives off - and your efficiency just goes up the chimney. Even in order to radiate the heat as you burn you will need a lengthy "flue" from which to give up the heat into your house. There may be ways to make this compromise work out but I'm not competent to say how.

Thermal mass can be had many different ways as you may know. One way is a thick masonry floor. Another, a thick masonry partition wall in the house. Look through all the many ideas in the RMH forum and I think you might find people who have some of the same issues you have.

Best luck.

Rufus