Time to get heat and insulation variable

Hi dear explorers

I'm discovering the RMH. I love the benefits and above all to help us disconnect from the Matrix by doing better

I need some help to understand 2 concepts please.

If I compare RMH with an efficient modern wood stove, what would be the difference between them for the heat generation ?
Would we get the room warmed faster with one or the other ? Do we have to wait the phase shift from the mass the get heat or is the room heated already directly like the wood stove ?

And is a RMH appropriate for insulated homes ? I've heard about people who needed to open windows because it was too hot with them
Is there a simple way to manage them properly ? and is there some situations where a simple wood stove would be enough ? or would a RMH always be useful ? in which ways ?

Sorry for my multiple questions but it was what came in the moment from a beginner explorer

Thanks in advance for any insight
Cheeers
Yvan

The conventional stove will put more heat in the room short term assuming same size pipe etc.   The rocket mass heater will produce as many or more BTU's but it goes into the mass being stored reducing the "instant" BTU's in a room.  So the apparent heat will be greater from conventional wood stove.  But the house will cool down rapidly after the fire goes out while the mass from the RMH will keep releasing heat from its mass.  The barrel style of RMH puts a certain amount of heat in room fast as the barrel radiates the hottest part of the heat from the sides of the barrel.  That heat being radiated actually helps the RMH rocket by cooling the smoke the first step helping the stove to draw.

Hello Yvan Rkm. Welcome to Permies! You ask excellent questions.

C. Letellier's analysis is valid.

I have long experience with high-efficiency wood stoves. They are amazing -- but expensive -- and good value over time IMO! But not everyone can afford the up-front cost.

The whole concept of the RMH is that is is not expensive to build, and available to anyone.

Another option: Sometimes people use an old wood stove for quick heat, but port the exhaust into a tonne of mass that will capture and deliver slow heat over time.

If you tell us your objectives, I think we can suggest a solution that will work. Cheers!

I agree with everything that C. Letellier has stated with one exception.

An RMH with an exposed barrel will create massive amounts of radiant heat.
With my digital temp gun, my 8" J-Tube RMH would create an orange glowing circle above the riser that read just over 1100F.
The barrel sides were 500+F easily. The rest of that heat is stored in the mass.

Your traditional box stove might run 500F+ on its top but it is not going to read 1100F
All of its heat is racing up the chimney and leaving the house.
It creates creosote, it goes cold within an hour or less of going out.
It belches clouds of toxic fumes that stink up the neighborhood.
Occasionally it catches the chimney on fire, sometimes burning things down...

There is just no comparison between the two.

A mass heater releases its warmth over the next 12 + hrs with no fire.
The chimney temp on a proper RMH is 140F-200F,  
No creosote ever, no risk of chimney fire.
A fraction of wood is used compared to a box stove.
Very little ash is left to clean out.
No clouds of stinky smoke wafting about the neighborhood.
You have this awesome incredible stove that attracts attention from all who hear of it!
Your fame grows as you become the super smart guy who built that awesome stove.
People come from near and far to see your creation and learn how to build their own.

Yvan,

Insulated or not, the calculations should follow this way:
-determine the heat loss of your house or room during the average coldest day of the year
-match the power of the heater to the heat loss
-in case of masonry heaters, select the correct size of firebox and bell thickness to reflect your climate and needs

For the first item, you may use online calculators. House with thick interior walls will distribute heat differently than a house with some paper thin dividers, so more than one heater may be needed.
Power of the masonry heater can be increased by firing it more often, for example two double firings per 24 h instead of just two single firings. It can increase the heat output by around 50%.
If you want to heat a workshop that is not used daily - you want quick heat - thinner bell, for living quarters larger mass can be used.

thomas rubino wrote:There is just no comparison between the two.

With all respect, I think this is a false dichotomy. There is a third option. A box stove is entirely different from a well engineered high-efficiency wood stove.

I ran a high-efficiency stand-alone wood stove for 15 years (Regency). I would buy one again, in a second.  Once up to heat, you would throttle it back and most of the flue gases would redirect to the firebox, and be reburned with superheated air. I shone a spotlight up the flue every year, and never needed to clean out any creosote. Not once in 15 years.

My father ran a fireplace insert with blower from the same company. He burned enormous amounts of wood (harvested and cured by his own hand). We ran a brush though the flue once a year for safety; it was one of those corrugated inserts inside a masonry chimney, so some creosote would build up. Still, super-efficient.

Granted, none of these provided 12-24 hour heat in the way that a mass heater would. But they were damn effective and efficient nonetheless. Not inexpensive though, and for many that counts! That's where RMH's come in.

Hey Douglas;
After I wrote that post I realized he was referring to one of the new cat stoves and not an old box stove.
Indeed the Cat stoves are very efficient, but you must admit they still send too much heat up the chimney compared to an RMH.
I have been told they can be fussy to get the sweet spot.
And as you mentioned, the cost is a factor for many folks.

As far as my statement about no comparison between the two stoves...
I stand by it, as long as it is a box stove vs an RMH...

Hey Thomas:
Given the comparison between a dumb metal box and a RMH, I think we generally agree.

The OP did mention an efficient modern wood stove, so I tossed in my 2c based on my personal experience. The right tool for the job etc.

BTW my stove didn't have a catalytic converter. But it did have an operator who paid close attention to fuel quality and proper operation -- which applies across the board.

Hi great people,
Thanks a lot for your answers and your wish to help
Sorry I don't know how to tag people so I will paste your names.

C. Letellier
Thanks.
If the barrel radiates heat, then we nearly have the same apparent heat as traditional or efficient wood stove ?

Douglas Alpenstock
thanks for the "excellent questions" it is just that I became really interested, Paul is a great motivational priest LOL
Yes I was talking about an efficient wood stove. I saw A Charnwood c-six (1500euros) my friends have.
There is indeed a difference between "a BOX stove" with an "efficient stove". I like the terminology for the first one
Like you say, the choice would be the upfront cost. The RMH would be around ... how much ?

thomas rubino
here is the super fame guy I love how you sold the tech
Thanks for this info with the gun ! Good to know.
You compared with a traditional stove. And it is really clear in this case indeed.
I'm talking about a modern high efficiency one, yes
Like the Sharnwood I mentioned above ...
Maybe I can test the heat going up their tube/chimney. If it burns it means too much heat is leaving above ?

Cristobal Cristo
Yes I suppose the adjustments will be done auto while feeling the heat we need. Depending on the house.
But the question would be how do we know what size of mass we need to build for our RMH ?
What do you mean by "thinner bell" ?

Cheers to all of you
Yvan