Installing Wood Stove in Camping Van
DingusMcgee last edited by toby
Why do this when I already have a Suburban propane heater? Radiant heat feels so much better than forced hot air convection furnace warming. Your cheeks report this fact as soon as sun rays or hot stove rays hit them.
Wood vs. Propane. Wood is free and so is solar but there are too many cloudy days during winter here in SE WY to depend on solar. I have tried a solar heated van and know. Propane heating may be a little more efficient than wood heating but using propane introduces more carbon from the deep fixed state into the surface cycling state of carbon that trees use.
There are a lot of design considerations to work through when doing such an installation to get a safe working system without to much cost and work overs. I will report on my endeavor to achieve a good system with more posts as there is to much to put in one post. Feel free to chime in any time.
There are sort of 3 types of wood stove designs that may seem suitable for a van installation.
Cast iron wood stoves are expensive ($900.00) and are likely to perform the best with little modification. Think air tight. They are the heaviest for a given size combustion chamber but the cast iron door and frame will heat warp the least compared to steel doors. Warped doors leak smoke.
Mild steel plate welded box stoves are much cheaper and lighter than cast iron stoves. You must get one with a cast iron door and cast iron door frame to minimize smoke leakage. I choose for installation the one cubic foot Guide Gear stove as it comes with a cast iron door and 75" of 3.5" diameter stove pipe for $128.00 on eBay. And it did need some modifications and tuning -- China made.
Can Stoves are made from various steel cylindrical forms such as barrels, drums and 5 gal buckets. The thin metal will likely burnout sooner than mild steel plate stoves unless the material is stainless steel. I do not know how the air tight the doors remain on the stainless steel models. There is a marine stove can version made of stainless steel that looks promising at $600 but the combustion chamber is somewhat less than one cubic foot. One cubic foot combustion chamber yields 25,000 to at best 33,000 BTU's per hour.
I did buy the EcoZoom stove thinking I could add a chimney. Before purchasing I could find no data on combustion chamber volume which now upon inspection is too small to heat a van. However it does make for one good small barbecue grill as it can do a good job with about 8 Charcoal lumps. Do not cook with this stove inside. Burning charcoal may seem harmless as it's smoke is colorless but the fluent contains harmful levels.
The Guide Gear Wood Stove Installed
I hear there is some kind of diesel heater that is the bomb if you have a diesel van. I will likely get a Mr buddy propane at some point.
Hi Nick G,
I had a 1983 electric Ford Escort that had a VW like miniature furnace that would fire on either diesel or gas. The furnace would soot up and need an occasional cleaning. It did not help defrost the windows.
There is a very important operational distinction to realize about the various RV propane furnaces and portable heaters.Atwood and Suburban propane RV furnaces draw outside air for combustion and expel the air to the outside after the heated air is passed through a heat exchanger that has cabin air passing over through the heat exchanger. The combustion air never mixes with the cabin air. Hence there is no CO contamination in the cabin and no moisture introduced. The situation is not so with the Mr Buddy Heater.
Bob Scarpelli bought a Mr Buddy propane heater to heat my climbing gym. I have Industrial Scientific M40 CO detector and studied the gym air when Heating with Mr Buddy. Even though the air felt & smelled awful there was no CO in the room -- maybe moisture and combustion products? I had had a similar experience heating the Little Rock gym with one those jet like turbo construction site furnaces with the door closed. We now have electric heat.
Another obvservation: smokers do not notice the bad air.
It is worth noting that after many years of use one of my Suburban RV furnaces steadily increased the cabin CO ppm. When the rise got to 40 ppm of CO I took the furnace out and apart and then applied vacuum cleaner air pressure to the combustion chamber and detected the source of the leak with soapy water.
I repaired the seam opening with Permatex Red RTV gasket Maker which is a special type of silicone sealant good to 650F. I then reassembled the furnace and started it heating. The temperature of the combustion chamber did not get close to 650F. The furnace is still mounted in the van and does work safely.
Suburban label Warning: Never attemp repairs by yourself.
The use of wood stoves in vans have some measurable criteria that are beyond casual safety. CO in very low ppm (1-6ppm) will not affect many people in any detectable manner. OSHA permits 8 hrs of work at 90 ppm. Levels in Mexico City get close to 300ppm. Continuous exposure to 400 ppm results in death and 5 min of 600 ppm is certain death. Consult further in Wiki for more discussion of CO health issues.
My van wood stove as set in the up in the van leaves 0 ppm of CO in the cabin air when burning with the doors & windows closed. The CO ppm has been monitored using the Industrial Scientific M40 detector & alarm on many occasions.
The other annoying combustion product from wood burning stoves in vans is smoke. This combustion product can be reduced to ZERO in the cabin air. There is no special stove or equipment needed to achieve smoke free air in a van heated with a wood stove.
To achieve zero smoke levels simply mount the stove in a manner such that the door is accessaable only from the outside of the van. You must seal the door frame portal to the van wall, seal the chimney stack and get the stoves' combustion air through a pipe that picks up the air outside of the cabin space.
My van stove build does not have an external door but that kind of a stove positioning is in the making for my RV. Why so? The Makita blower shown in stove picture below the stove can rid the van of smoke easily when the doors are open. It is much harder to clear smoky air from the RV. Maybe a leaf blower could generate enough turbulence to get moving air to every texture and cranny?
toby last edited by toby
@DingusMcgee RTV Red every where! Sacrebleu!
Interesting propositions. School bus conversions from the 60's typically sported some form of wood stove heat. Never considered applying to a space as small as a van. Seems like the external feed door would be safest and most environmentally pleasant but then a bit of a pita to feed during inclemate weather.
I favored portable team husky heat bitd. My regular setup was a camper shell and reasonably decent three season down bag made by Wilderness Experience. When it got cold, I brought one husky in to bivvy with me. When it got extra cold I brought both in to bivvy with Dad. Thereby inventing the patented Team Husky one dog night and two dog night cold bivvy scale.
Alas, also a bit suboptimal during inclement weather...
I have used one of my Aussies that has now crossed the River Styx to add heat to the sleeping situation. My Old English Sheep dog of now will not sleep inside even if it is -10F outside. I am a little surprised that you could get a Husky to enjoy humanly warm temps.
For one of my van endeavors to use less petro to keep warm on ski trips I converted the back end of the van to a super insulated sleeping chamber. The mattress area was about 70" x 80" with about 36" height. At temps of zero F outside with the dog, the girlfriend and me inside the cabin temp inside would get down to about 56 F by morning. It seemed the food digestion of the three of us would last until about 2 a.m. And the cabin temp would slowly descend after that time from the low 70's to the 50's.
The superinsulated sleeping chamber had the same problem as superinsulated houses do. When the oxygen per cent decreased to the low 19% range I stared getting an anxiety feeling and wanted to go outside. To remedy the low oxygen % I installed a small computer fan to push front cabin air into the sleeping chamber. Well that van is history as the V10 motor got a rod clatter and V10's cost about $10,000 to rebuild to turnkey completion..
But more to the point of why does one want a furnace? In the winter days are short and evening temps are low. Who wants to spend 16 hrs lying in the sleeping chamber awake for 4 hours? The current van has a n extended top (about 76" height) permitting one to standup and walk around while cooking and during evening chat. If this event is moved outside in the evening you will be fighting cold temps. Van life does not have to be Mtn Climbing life.
"...to a space as small as a van." Yes, one bumping into the hot stove pipe will melt the Patagonia nylon jacket faster than your $$ left you when acquiring the excellent clothing.
If the wood stove installation is made smoke free, the result will most likely be CO free. There is one counterintuitive happening that gives some mental relief when you know the likely result for smoke in the van.
Smoke is generated inside the stove as wood is heated. This coke gas is released from the very hot wood. Coke gas is smoke like but exits in the stove as uncombusted and after combustion the coke gas is converted to CO2 when fully burned. Temperatures in a hot stove increase from the feed door to the stove pipe exit.
The unavoidable situation of having to feed the stove wood necessities having the door open briefly and invariably some smoke gets into the cabin air. I was curious about how much CO got into the van while recharging the stove with wood. After many measurements with the Industrial Scientific M40 meter I have concluded it is likely zero CO into the cabin air as the meter responds very quickly. I have tried it on a non catalytic car exhaust -- instantaneously all whistles and bells go off.
Conclusion: the smoke exiting out the door which is from the cooler end of the stove must be warm uncombusted coke gas. As a stove habit I do push the burning mass of wood as close to the stove pipe exit as it will stay during each wood recharge. There is always CO in the fluent exiting at the stove pipe top when the stove is either warm or hot.
I wear a 3M N95 dust mask when recharging the stove as I can get asthma from some smokes.
The next most important safety concern after CO levels is the stove pipe exit from the cabin to the outdoors. Simply running the stove pipe through a hole in the van ceiling may work but it may be a fire hazard. The devise that makes a safe stove pipe passage to the outside is called a thimble.
There are municipal statues for such pipe exits and they usually incorporate double wall pipe. For a wood stove application the inner pipe must be stainless steel, the inner aluminum pipe used in double walled pellet stove pipe will collapse with the fluent temps of wood stove. There also is a commercially available thimble for wood stove apps. 3" double walled wood stove pipe run about $4.00/ in and you would need about 100", unless you make connection adjustments for each change of double wall to single wall.
It is possible to safely use the 3 3/8" singe wall steel pipe that came with the stove when making a thimble good enoughfor suppressing the elevated pipe temperatures outward at the exit hole.
These two different thimble uppers and bottoms were made from electric stove element grease catcher basins found just under the heating element. The black one is a GE porcelain coated surface and the generic shinny one says chrome. About $5 a pair at Home Depot.
You will need to hole saw them out to fit your stove pipe diameter. The porcelain coated one seems to saw harder and may dull your hole saw sooner. Drill about (8) 1/4" holes in each around the perimeter and these holes must be aligned if you want to use pass through bolts.
Saw a 7.5" diameter hole in the van ceiling in a location straight up the bolted down stove's pipe attachment hole. More than ideally this hole location should not go through any roof beams or electric wires. Cut electric wires can be added and spliced and then routed to the outside of the 7.5" hole. I did once cut a beam in a Ford van roof. It is not the end of the world for the van roof as there is some structural design redundancy in these roofs, but not for a swimming pool on top.
There is likely one of these 3 types of material (s) at the roof exit hole. Simply steel, fiber glass matt composite or the likes of blue styrofoam sandwithched between plywood with an occasional wood structural 2"x 2" and aluminum covering on the roof. The last mentioned here is RV materials construction and it takes the most fire retartdents to be safe.
Let's go over a possible RV insulation method. Push back or remove the blue foam so there is a void of blue foam about 2" deep beyond the hole cut. Reroute electric wires so they are in this void. Fill this void with Great Stuff Barrier Insulating Foam which has an ignition temp of 459F. Next cover this dried foam with a thin layer of Red RTV Sealant 650F. And be sue to coat the wood edges around the hole with Red RTV. Next add a layer of 3M Fire barrier Sealant about a 1/4" thick to the sidewalks of the 7.5" hole. This sealant is advertised to expand 3x from dry room temps as it get to 1000F. Maybe $15 for a 10 oz caulking tube. Cleans with soap and water.
Before bolting the thimble together pack in about 3/16" of RED RTV sealant around the upper and lower grease catcher pans perimeter-- thimble edges. Tighten the through bolts after RTV sealant has cured -- about 24 hrs. This layer of RTV sealant will measurably increase the contact conduction resistance between the wood and the steel of the thimble. Wood chars at about 120C and dry wood can ignite at about 150C.
Lastly from other hole in the grease catcher basins fill and pack the interior void with yellow ( less itch) fiber glass insulation until you feel with a poker that it has filled the void. I covered the top hole with aluminum metal adhesive duct tape to keep water out. A note on fiberglass at temps: melting temp is about 1200F + . It melts but it will not catch fire. If this temp is a problem for your situation, fill the inner half of the void with Imperial Furnace Cement (black) which degrades at 2000F. Then fill the outer annular section with fiber glass. The 3M Fire barrier may expand to much while in this application and at this thickness.
While using the Fluke laser temp sensor device during a very hot startup I detected temps less than 650F just above the damper. Also note the RED RTV sealant above the damper is still firm.
Sealing the gap between the top thimble and the pipe would make for a waterproof roof exit. I have tried RTV but sealant but the hot pipe expansion exceeds the stretch capacity of the sealant and it tears away from one surface or the other. I will cover a way to seal this gap later.
On eBay you can get a type K thermistor and RO device for about $15.00. The K thermistor can read temps to 2501F. I have one but have not used it for this testing as the fiberglass has never gotten near the 1200F melting point when measuring its surface temp using the Fluke meter.
Note : before building the thimble read my next post on checking for stove pipe size adequacy as sometimes stove are sold with too small of pipe which means getting a lot of smoke in the cabin when recharging.
Stove Pipe Size (cross section area) is proportional to the combustion chamber. This means that a 3 cubic foot stove would use a stove pipe of about three times the cross section area of a one one cubic foot stove. As the fluent does not travel very fast one can assume plug flow to justify the assumption of proportionality.
Ideally the stove manufacturer will have affixed a round pipe flange of a diameter large enough so that when recharging the stove little smoke comes out the open door when of course the damper is fully open. Such thoughtful design is not always the case. I purchased the 3 cubic foot Guide Gear stove which included stove pipe of 3 3/8" I D. The oddity here is that the one cubic foot stove comes with the same size stove pipe.
The one cubic foot stove performs great with the 3 3/8" stove pipe. As a test to determine whether this size pipe was in some way a little oversized I turned the damper a little until smoke would come out the open door. The pipe size does seem slightly oversized by this way of measuring. At any rate I have concluded from this testing to say 90% of the pipe cross section area would be adequate to get little smoke outflow through the open door when recharging.
From this data point and the rational condition that a stove of zero chamber size would need a zero cross section pipe one can get a number for cross section area of stove pipe needed for stove volume. This one point experimentally based coefficient is 8 sq in cross section per cubic foot of combustion chamber. Apply this coefficient to the 3 cubic foot stove the stove pipe needed would have 24 sq in cross section. Nominally this calculates to 5.5" diameter pipe which may not be cheaply available. Auto parts stores can order 5" and 6" steel exhaust pipe. A 10' long 5" diameter is $59.
As the 3 cubic foot stove is a little oversized for the size of the RV, it is likely I will seldom fully charge the stove so the choice 5" pipe at 19.62 sq in vs the 6" pipe at 28.26 sq in is to try 5" pipe. Over sized pipe results in slower fluent speeds which is okay but having a damper for bigger pipe may be more useful to save warm fluent longer so to get more heat off the hot gas. A strong fluent speed (vs a slower fluent speed of the same volume ) will have more dynamical inertia which translates to less belching and reversals of smoke direction travel. But with too small of pipe cross section you get stagnation and smoke accumulation in the top of the stove.
The 3 cubic feet Guide Gear Stove with 3 3/8" stove pipe. The 2" pipe on the floor and left of the stove is for external air intake.
looks dangerous as heck in the small space of a van. I get it in a schoolbuss but there goes your whole living room in a van to be replaced with a scorching hot woodstove..
Okay NickG, is appearance reality? First of all the picture of the stove you refer to is in an RV not a van. Secondly the width of this RV is 8' which is the same width as a school bus. It seems you have approved wood stove additions for school buses?
Even with the space the wood stoves takes I likely have more space than any 6' wide van of the same length. So your accusation of the wood stove installation taking up all my space is both somewhat unverified and does not account for how much space 2 people might find adequate.
"...scorching hot woodstove" ? It seems you have little experience how low you can regulate the surface temp of a wood stove when you have adjustable flow for the external air intake -- combustion air --. One can hold a hand on a 160F surface. I have had this stove at 200F for some time which feels just a little warm for the hand but likely I can get steady state burning with a surface temp of less than 200F.
As for the RV, I have taken out the toilet, the generator (I have 600 watts of solar panels), the refrigerator( an energy pig) which has been replaced with a top lid Dometic which one can sit on or sleep on, the Davenport, the hot water tank type heater which has been replaced with a tankless, the 30 gal water tank is gone, the table is gone, the fixed chairs are gone, the air conditioner is gone along with the various antennas. And you accuse me of now having little space after the stove installation? Unfounded.
whatever floats you boat.. hard to tell from you photo how much space you have. the photo makes it look pretty cramped. personally I don't like sleeping in the same room as my woodstove. Sounds like you are super handy and knowledgable and have it working the way you want it, If its truly the same size as a school buss then you should have pleanty of space for a separate bedroom.
Spacious and Gracious living in an RV or Van? Maybe for some but I keep one eye on my resource consumption. The penultimate couple for living such a life (rock climbers with part time jobs) of less than usual resource consumption has to be Herb and Jan Conn. They did have a van but lived in a tiny house-cave. They are very small people. The first time I saw the inside of the Conn-cave, an offer FEW got, I was confounded as to how they could spent an entire winter in this little place. There was a wood stove.
No doubt, they moved around carefully. There is no place for a bull in a van's china bowl. I now understand some of how to manage life using less than what the commercial world offers and try not to simply transfer the ammenities of the ways we live our residential lives by making miniature replicas of such items and incorporating them into van or RV life. But alas, my van is way bigger than the Conn Cave. Never-the-less, some understand how less is more.
Where does the RV fit into my life? Maybe I will drive it down to where the homeless stay and offer it up with the wood stove door pad locked? All of 'em would know how to sleep in it but could they manage the other changes?
The point here is that just about everybody has the skills to manage their lives when asleep but do they have the skills when awake to adjust and yet make material changes to what had been a lousy way of doing things? You know, the guy took the toilet out of here, where the hell are you supposed to shit?
Oh! Forgot something -- I try to keep the other eye on staying healthy.
Sizing the inlet air pipes follows from knowing the stove pipe cross section size area. These pipes will get combustion air from outside the van.
The air inlet holes like exist on the door of the Gear Guide wood stove will let too much smoke into the cabin. Seal these air passage ways with Red RTV sealant, maybe leaving the bottom center hole for visual inspection and pumping air into stove with the cordless blower when rekindling a fire from a few hot coals.
Using the equation P*V = MRT, a gas law, we can get a number as to how much the cold inlet air will expand after it is heated and is on its way up the stove pipe. With wood combustion temperatures around 1100F and then some cooling the maximal air expansion ratio is at max about 3x the inlet air.
Assuming plug flow in both the inlet air and flow in the stove pipe, a good size for the inlet cross section area is 1/3 the stove pipe cross section area. This cross section size likely will get your stove to heat from cold to steady state hot quickly and with less smoke than a smaller cross section area would. But this size cross section area will allow your stove to burn scorching hot.
You need not reach this cross section area with just one large pipe as 2 pieces with the same total area would also suffice.
A damper on the stove pipe will slow such a run away fire down (often though overpressuring you door gasket seal and letting smoke into the cabin) but some sort of inlet air regulation works much better than simply a damper. A damper is useful when in the smoky fire stage of stove warm up to engage it horizontally and look for leaks in the system.
There are two easy ways to regulate air inlet flow. Always put the inlet holes opposite the stove pipe exit and down near the floor of the stove.
A ball valve with a handle is suitable whether you pick up the intake air through the floor or the side wall of the cabin. The brass versions of these valves are $$$ but the white PVC versions are sometimes 1/7 the cost of the brass. After about 3 steel pipe fittings from the stove box the air inlet pipe temp of ball valve will be quite close to air inlet temp. This big reduction in temperature comes about due to both a high contact conduction resistance accross pipe fittings threads and the cooling due to the moving cool inlet air.
A very cheap and satisfactory way to regulate inlet flow when the pipes goes through the sidewall is to put different size offices on the entrance end of the inlet pipe for startup to steady state -- obviously they are on the outside. Below is a picture of such a set up.
Pipe size is 2" and fully open works great for startup. To get a long slow warm burn on a big charge the 1 1/4" office regulates the air so the fires burns on this low rate. You have to experiment a little to get the right reduction for the burn rate you desire. I carry a Fernco cap for smothering the fire. A 5/16 socket driver is the ideal wrench for these Gear camps.
Case in point about doing things the way we think is cool or whatever:
A couple days ago Bob Scarpelli, when told about having the stove refueling door outside the cabin, Bob thought this was a most uncomfortable way to have to do the recharge chore.
My reply: Bob, you refill your pickup gas tank by going outside the cab.
Cabin living my whole life I am adamant about wood dry and under cover, woodbox next to stove and no tromping through the snow to get wood. Wood needs to go directly from woodshed to interior of house without going outside. I see houses with the wood out in the snow covered with a tarp and I am horrified at the crudity of their set up Often the house is 100 times nicer than mine but shit I don't have to put boots on to get my wood.
RussWalling last edited by
FritzRay last edited by
Russ? Please tend to your own web site.
The finest of high $$$ wood stoves let smoke into the house rooms when recharging them and likely they give off some back flow smoke through the air intake vents when going from cold to steady state hot. A wood stove in a van goes from cold to steady state hot each road trip you take. Yet some troll that knows little suggests, "go buy something." I say why throw good money for something when the unmodified expensive product will not out perform your modifications of a much cheaper product. Perhaps that foolish consistency he displays (go buy something) is just the hobgoblin of litttle minds?
It seems anyone with any sense of boundary containment would understand that having the access door outside and a good seal on the exit stove pipe likely yields zero smoke for the van cabin air. As far as my design for zero cabin smoke is concerned it matters little where you store the wood.
I do have a Wager induction moisture meter. Often wood stored indoors here in SE WY can be less than 6% moisture. Sure you get less smoke burning low moisture wood but if the stove door is outside the van etc the extra smoke from say 10% moisture wood is of little concern. On a typical van venture I take some wood with me and acquire some locally using a cordless 18v sawzol with a pruning blade. Often I find wood & kindling at 10% or dryer.
A new mother can wake in the middle of the night and change a baby diaper without whining. Are you a whiner about having nocturnal duties? So be it. I have no need to put on the shoes even when there is snow outside for short duration chores like pisssing or recharging the stove. The wood box can be moved to the drivers seat whose door is next to the outside wood stove door entrance.
If you get cold for these little bouts outside, your blood sodium may be low. I bring a bag of salty chips along so blood sodium gets high and I FEEL quite warm when taking on exposure ventures in the winter.
One can find many anecdotal posts on web about the harm of wood smoke but here is a report from a study with some quantification: