The thought is... remove the fire place insert from pic-1 (this is an non chimney supporting insert), use this gap from the insert removal for the fuel input part of the J tube with the oil barrel and initial mass adjacent (where the duck head poker is). vent tube leaving the barrel heading nearly straight up to the second level. the existing bench would be renovated/excavated/replaced to include the exhaust pipe works, eventually exhausting into the second fire place.
Patrick Rahilly : Welcome to Permies.com and A Big Welcome to the Rockets Stoves/Mass Heater Forum Threads, with over 18,000 fellow members, you are supported by
a very diverse group who want to talk about what you want to talk about ! You will long remember your first Few exchanges here at Permies. Speaking about Which - you
should go to permies.com(s) sister site richsoil.com and click on/go to rocket stoves which will take you to a set of R.M.H. builds done by Professionals or as directed by Pros!
This is not the Jreck Videos from one-time-only contributors in U-Tube Land !
For a 1st project you have set the bar very high, It is difficult to tell From just the pictures we have seen so far, but I expect that to the left and above the bottom Wood Stove and the upper levels wood stove here is liable to be a rather large void, with some wasted space,however a re-fit that uses that area could create structural problems, and
Great care most be taken that we are properly creating air gaps,reflective radiant heat barriers, and insulating around any 2X4 wall studs and hangers. Do you have an
Inspection panel now that lets you look in there to see how your current system is laid out? You spoke about channeling the exhaust of the R.M.H. up to the second level to
create a Thermal Mass Bench, and then route the exhaust gas to the 2nd Wood Stove !
I am positive that your Two wood stoves have two separate chimneys, or at least did in the original Architects drawings, This is definitely the way to go here and I mention it
because you said you would run your pipe into the Second wood stove! If you don't have a clear way to see how the two wood stoves are piped now, I would climb up on the
roof and count the number of flue pipes within your chimney ! R.M.H.s should always have their own chimney !
Are both levels of your Split level setting on cement slabs, and how are they tied together ? OR, Is the second upper level setting above a full or part Basement with
conventional Wood structural 2 X (?)?
As a help to visualizing the amount of work and materials needed for this job, I would like to suggest going to ernieanderika.info, to copy a Set of D.I.Y. Site
Planing guides. To find this guide from their home page ( They are The Moderators of This Forum ) click on/go to 'Consulting and Booking Events' -upper left of page- and
again in the upper left- click on the site plans prompt ! This should help you visualize your project, and protect you from missed steps that can really mess up a R.M.H.
I have pointed out everything so far Not to be bossy or negative, just to help you visualize your project more completely, I do have a final question about why you want a
Rocket Mass Heater, and why in that location ! In the past has that been the most used room in the house, or if that becomes the center of the house is it going to interfere
with something important like meal preparation ?
In order to get maximum use out of your R.M.H. It will need frequent feedings of small very dry wood, at start up every 1/2 hr or so until you get a good bed of coals
and the fire brick inside are glowing red. Then you may get way with feeding it Larger wood every two hours! Again to get maximum heat this kind of feeding pattern must
be continued for 6 to 8 hrs To Get 24 hrs worth of Stored heat in your Thermal Mass. If you have picked this location because it is out-of-the way and are not willing to give
your R.M.H. Pride of Place in the center of your house where it can be easily fed, then the need to leave your location to frequently feed your R.M.H. will probably grow to
be a chore rather than a pleasure !
Is it possible that your second levels Wood Stove location would be better suited as the location of your R.M.H.? I hope that I have in some way helped you with this R.M.H.
project! For the Good of the Craft !
As always, your comments and Questions are solicited and are welcome ! Think like Fire!, Flow like a Gas!, Don't be the Marshmallow ! PYRO-Logically BIG AL
Success has a Thousand Fathers , Failure is an Orphan
Thanks for the reply, no bossy-ness or negative-ness taken.
The two fire-places do have separate flues but share the same masonry work. The fire places sit side-by side, albeit elevated on opposite sides of the masonry work.
The placement, the first fire-place where the thought of placement of the barrel and initial mass is in the kitchen/dining/entry area and is wanted for alternative cooking area and heating. the reasoning to go up to the upper bench for the remainder of the mass and exhaust works is the living area that has huge cathedral ceilings with a ceiling fan to help circulate air, but is a huge air void and expense to heat using conventional air heated systems, i.e. heat-pump. This placement is very much in line for function, but also should give it the much deserved "Pride of Place". The lower level floor space is about 250sqft, the upper about 350sqft
structurally, the sub-floor on the bottom level/first-fire place area is basement/garage below, the support beams are 2x12's with 10" spacing. On the floor level, the wall behind where the barrel would go, and the subfloor rests on a reinforced cement wall even with the floor, 18" out from the cement wall, even with the outer edge of the insert/chimney, there is a supporting wall beneath. ...moving to the upper level, there is a 3-4 foot crawl space, again with 2X12's at 10" spacing. The existing bench rests on the floor without any additional support below and is not structurally part of the chimney which is constructed with cinder-blocks and the brick facade (no bricks in the crawl-space, just bare cinder).
I hope this is clear and gives a better idea as for the want and helps with the feasibility aspect of my inquiries.
on another note, last winter (our first in this house) we went through 4 cords of wood and still had an astronomical heating bill. Beyond the hope of the RMH helping with the heat bill, I want to cut down our wood use load as it's collection or purchase is costly in time, energy, and/or pocket. I also, have worked a bit with coppiced culture and AF and hope to have our own regenerating forest to fuel the system in effort to be more self-sustained on our property.
Location: Northern New York Zone4-5 the OUTER 'RONDACs percip 36''
Patrick Rahilly : I am visualizing a rather steep building lot with access through a Garage with a split level building sitting above, am I even close ?
There is a very common type of 'Fossil fuel fired (hot air ) furnace' that pulls all of the return air, that is to say all the air that will be reheated- down
from the ceiling, Running it past the Heat Exchangers, and then discharging it at ground level, this system puts the force in forced air circulation !
To work well it needs to move a large volume of air, it can only do so one of two ways, ether with large sized, large volume duct works, Or by rapidly
flowing air at high flow rates ! This latter system is often noisy, and/or Drafty, to properly position, size and create adjustable flow rates, like is common
with most Air to air Heat pumps , requires a skilled HE.ating, V.entilation and A.ir C.onditioning (H.E.V.A.C. ) Technician who can follow the blue prints
created for that build by a artistically talented building Engineer who is well grounded in his Science, doing the ductwork so that it all works quietly is as
much ART as Science !
Ceiling fans are nice, I would first check that the are turning in the correct direction, In Summer you want them to encourage stratification of the hot
air at the ceiling peak and in the winter you want them to turn in the opposite direction to pull hot air down from the ceiling, and into the living space !
Take the time to prove to yourself that your fans ARE turning in the right direction for the ceiling, helium party balloons might be a useful tool !
Your local utility may have a plan to help you determine where and Exactly how to make energy saving improvements in your home ! They are
probably the best source of information in your area as to state and federal programs to reduce energy usage also ! I is possible that your local utility
is required to be a neutral third party in this, in which case you will have to discover on own own who can more cleverly find you savings before you
sign on the dotted line !
Your floor joists should easily handle the weight loads of a massive Thermal Mass Bench, and you should be able to recirculate all of your masonry
debris within, Please remember that you will need clean outs that are well placed to be accessible ! 600 square feet is easily within the heat range
of a well made 6'' system, if you can modify your Cathedral Ceilings stratification, and a 8'' system should allow a small bench on your 1st floor with
most of your thermal mass used on the second floor !
A word of caution, cement and especially cement cinder blocks will start to fail if exposed to long term Temperatures over 400 F !
You have convinced me that you are serious about a R.M.H. in your future, If you have not already done so, I would recommend going to -
cobcottage.com to pick up your PDF Copy $15.oo of Evans' and Jackson's Great Book-' Rocket Mass Heaters' , there is Still,
No Other Book in any language, with more Rocket Stove/Rocket Mass Heater family information ! (and I Don't make a dime !)
Please send us some more pictures, refer to my 1st Sentence, I am still guessing on your lay-out ! As always, your comments and questions are solicited
and are Welcome! For the Good of the Craft ! Think like Fire !- Flow like a Gas!- Don't be the Marshmallow PYRO - Logically BIG AL !
Flow like a Gas!- Don't be the Marshmallow
Success has a Thousand Fathers , Failure is an Orphan
well, you nailed it. Yes, this is a steep house, and yes there used to be an oil fed furnace that pulled spent air from the ceilings returning it to the furnace to be reheated, however, the system was revamped in 2009 (prior owner) with an electric heat pump, the ceiling intake vents were nixed and a new intake installed in the stairwell to the basement, hence the lack of air flow from the high points to the low points. We just put in the ceiling fan, this is the second, there are plans for 3 more additional fans, and yes I am familiar with the downward/reverse settings of the fans for summer/winter respectively.
We did have the power company out (which is actually a not for profit co-op! wow huh? I moved from the land of PG&E where they were trying to shut down all public utilities) and had an energy audit. All clues led to the furnace. There are new windows, thick insulation, essentially a green house buffer surrounding the building, but, yes, the lack of air flow from high to low killed it and to get an HVAC engineer out to fix the system is probably on the lines of 10k plus, which still doesn't fix the problem of trying to move a little more off the grid, hence, the RMH.
So, Yes I have bought the book (hard copy) and read it. It even came signed with a "good luck!". I came across Permies and E&E back in January, bought the book, and have contemplated the system with my wife since.
I have been in contact with E&E and hoping they will chime in at some point.
Thanks for the heads up about the cinder block heat threshold, we will have a lot of heat protection/insulation to do, but thinking about insulation cement doesn't come at the top of the list.
Next question, as I am to understand, the RMH system works with the exhaust ducts exit continually rising. If this statement is true, is there a problem with the initial out-take from the barrel going nearly straight up? Is there a needed length of run pipe post barrel to keep a hot spot from forming/melting the duct work? I would assume yes, but, has this been demonstrated or is it known (the necessary length of pipe run post barrel that is)? Perhaps, ensuring the install includes extra length of high heat tolerant stove pipe until the temps drop below 300 or so. Answers/speculations welcome!
Location: Southern alps, on the French side of the french /italian border 5000ft elevation
About the pipe raising all the time, no need. An 8 system can push nearly up to 40' of horizontal pipe. Can't push it against strong winds tho. An elbow sets you back 5' shorter, two 10' shorter iirc. You can gain "original" draft with a vertical chimney. Thought, if the gasses within the chimney are too cold compared to the outside air. It won't work at all. That happens sometimes in the summer. Hence the need of a primming door at the bottom of the vertical chimney.
There's some guys at Donkey's board thinking of retrofiting old cook stoves with a rocket burner too.
Question, is your wall, stone faced on one side, brick faced on the other; hollow? If yes, that would be a fantastic bell for an horizontal batch rocket. Problem might be up top, where joists might apear in the massonry.
Patrick : If the original duct work allowing air to be pulled down from your cathedral Ceiling is still in place and was not hooked up to the Replacement Heat Pump, you could try
a simple ducted fan with a multi speed motor to pull that air down into your living space, again you might end up with whistling ductwork or worse.I can't ignore the possibility
that you might find a small used air conditioning unit that would attach to your existing duct work, with its Heat sensor moved to a location in your cathedral space, and set for
moving air only-! You might be able to create a custom air recirculation system separate from, but working with the Heat Pump !
I really need to see a few more sketches/pictures of your layout, I am afraid I can't follow your description ! Trying to visualize the layout caused me to consider the following -
Some of these insert type of wood stoves have very poorly crafted dampers located in the smoke shelf area just above the wood stove, and there are even a few models that
rely on an Air tight-ness that is not really there, to close off their Vertical chimneys from exhausting all of your heated living space room air.
From your willingness to accept my description of the layout of your house, it sounds like you have an unheated garage/basement area that your Kitchen/Dining room Cantilevers
out over, that means the Kitchen/Dining room floor is an outside wall, Think about the sound deadening properties of good insulation, can you clearly hear when someone is in
that space from the kitchen ? Do you have an automatic garage door opener that alerts the house that 'daddies (or mommies) home !?!!
I understand some about Coppicing- it seems to keep certain types of trees 'forever young' and pollarding! but what is AF ?( We Need our own forum at permies )
Ernie and Erica Wisner have a site planning area at ernieanderica.info , It is a very useful D.I.Y. planning aid, I often recommend it to people to help them visualize their
R.M.H. build from the very beginning to The finish. It is possible that they could come and do a workshop for you, they came East Last year and I was able to assist on the Work-
shop and on the build, I learned tons more, and now consider them true friends ! Hope i helped a little - For the good of the Craft !
As always your comments and questions are Solicited / Welcome! Think like fire!- Flow like a gas!- Don't be the Marshmallow ! PRYO - Logically BIG AL !
Success has a Thousand Fathers , Failure is an Orphan
It does look like you've got a reasonable location in mind for the rocket mass heater - near the center of the space to be heated, and with the bench forming a useful piece of built-in furniture.
A few things I'd like more information about:
-- The foundations / load-bearing for the mass heater.
It sounds like there are a pair of existing, masonry, load-bearing walls below the lower hearth, and the upper hearth is also partially supported by the masonry wall of the garage below?
Although adding the rocket mass heater in place of the existing bench may change the weight location somewhat, it shouldn't be a huge change in the total weight to be supported. You might need to expand or beef up the support directly below the combustion area of the new heater.
-- Clearances to combustibles: It will simplify several things if you can remove any combustible materials in the immediate area around the rocket mass heater, for example by replacing the half-wall there with a masonry half-wall in the same style as the fireplace. It might pay to examine the floor structure from below, and see if it's practical to cut out a 4' by 5' box and re-frame the floor joists so you can support the heater directly on the masonry (non-combustible) structures below. People have built rocket mass heaters over wood floors before, it's not impossible, but it does turn out to involve a bit more work to protect the floor from the heat.
I don't think you'll gain much by removing the lower fireplace insert. To clear enough room for the new rocket mass heater could involve removing structural elements of the existing masonry.
I realize you're already committed to a fair amount of masonry alterations to hollow out the existing bench. I congratulate your ambition and hope you find the existing bench happens to be hollow; it would save a lot of work.
I suspect the structure of the two chimneys is tied in rather more closely than the bench. You'd risk possibly cracking part of the chimney lining if you do the work with rough-and-ready tools. Do you have access to a masonry saw or drill for cleanly cutting into the existing masonry? They can often be rented, or a local mason might be willing to do this aspect of the work on your behalf.
Making the rocket mass heater on two levels is well within the design parameters of rocket mass heaters, and has been done before.
-- The other thing I'd like more information about is the location and climate of the house. If you can find your nearest (climate-similar) weather station from this database: http://www.huduser.org/portal/resources/UtilityModel/hdd.html and describe briefly the insulation and wall structure of the house, it will help me give you a better idea what size heater may be appropriate. I understand the whole building, both levels to be heated, is about 600 SF with an unheated garage/basement below?
-- Finally, do you have any concerns about maintaining the building's insurance or up-to-code status? Rocket mass heaters are kind of an oddball category, some insurers respond well to them while others can be reluctant to insure them. Same with local building code offices. The heaters are exempt from EPA by weight, and most (but not quite all) of the building methods can be done so as to comply with the Masonry Heater ASTM standard. (There are a couple of points in the ASTM standard that are ambiguous when applied to rocket mass heaters.)
If you would need local approval in order to pursue the project, we can offer some documents by e-mail that might help with the initial conversations with any officials / agents.