RV Furnace In A Cabin? OT But Worth A Shot!

Scott.ID

Member
Howdy all,

Cabin isn't really a tool, but a lot of smart guys here.

12x20 timber frame cabin in the mountains, WAY off the grid but I use batteries, 12v lighting and such when I'm up there. Also use generator for power tools but run out of fuel after 5-6 hours if I try to run milkhouse heater. Also have to vent outside if I try propane heaters with my asthma and COPD.

Why could/couldn't I hook up a 12v 20k btu furnace from a RV? Maybe 30k btu? No insulation to speak of because interior is all beams and finished T&G, wife unit doesn't go up there in winter but If I insulate I'd have to pull it all out come spring which could get spendy.Ducting would be nice, and I've got several propane tanks. I've been told both yes and no by local RV shops, but figured I'd get a straight answer from you guys...

Scott in North Idaho
 
Isn't that what they use in the fancier ice fishing shacks? Other than the fact that your floor doesn't have fish in it, I don't see much difference.
 
RV furnaces are usually noisy and will drain a battery fairly quickly, why not use a wood stove. If it's installed properly it shouldn't bother your asthma. They are so quiet, that's what I like.
 
Because you don't have any insulation, I would think that a radiant heater would work the best. It will not heat the whole cabin as well as a forced air type of heater, but it will use much less fuel.
Many are not vented but some are.
If you are interested in using solar panels to charge your batteries, go to Open Roads discussion forum which is a RV site. They talk about solar panels there.

Dusty
 
have older 24 ft. camper trailer. 1960's. furnace is millivolt system for thermostat, requires no power, vented thru roof, wall mount style mounted on side of closet near center of camper. it will run you out in a few minutes if you turn thermostat up. something like this would work well. older slide in pickup camper had similar smaller unit with thermostat built into control valve, it vented thru wall, keep looking, old campers are junked frequently.
 
Scott,
For around $150 Lowes and many others sell a portable 6,12, 18000 BTU cermanic IR LP heater. Mine is vent-less. Burns very clean, no power required. Comes with an O2 sensor. Mine uses 20# lp tanks. I think mine is called Mr heater. There are many models on ebay and amazon too. The upside to portable, I can use them anywhere.

A friend has the same heater but his is vented. He uses his as a backup heat source, like I do.
George
 
Both campers that I have had the heaters were NOT noisy and what little power the thermostat pulls is minimul so battery would last a long time.
 
With no insulation anything will get spendy. I would think about that. In the long run, it will help in the cold weather and also keep you cooler in the Summer.
I have a well insulated smaller hobby shop, ( 12'X 12' ) that I heat with an inferred ventless heater that is wall mounted. It's clean and uses very little propane to keep it toasty warm.
 
Yes, we had an older camper that had a quiet furnace, the fan was optional, would work without power, Now we have a newer truck camper that has a furnace with an ID fan and it's quit noisy.
 
I put one in my cabin. I did it because it has solar power with 12 volts DC. Only get AC when I use an inverter that robs power. So an RV furnace working with 12 volts works nice. 32K is not very big though. RV propane furnaces run around 80-85% efficient. A furnace rated with a 32K rating likely puts out only 26 or 27K of heat inside the cabin. The rest goes out the vent.

I also use a Procom 30K BTU non-vented catalytic heater that works great. It actually uses all that heat to heat the cabin. But I don't sleep with it on - just in case.
 
Scott, an RV furnace is simply an LP Gas fired unit that uses 12 VDC to operate its fan and electronics (instead of 120 VAC like in a home) and I see no reason why it knows the difference between if its heating a cabin or an RV provided its properly installed and vented. BUT IM NOT AN RV OR FURNACE EXPERT SO TAKE THIS AS BILLY BOBS ADVICE. ITS LIKE MOST ADVICE HERE, NOT WORTH RISKING YOUR LIFE ON

Sure a non vented catalytic type of heat is more efficient and doesn't require 12 VDC power, but fresh air and venting is obviously critical. It makes sense provided you deal with fresh air and venting.

That being said, its not all that expensive or complicated to rig up true deep cycle battery or batteries plus a solar panel and solar charge controller to power that furnace. That way venting isn't as critical as if you used a non vented heater,,,,,,,,, you have 12 VDC to run the furnace,,,,,,,,, and you could add a 12 VDC to 120 VAC Inverter to provide low power 120 VAC to charge your phones etc. Think about it

NO WARRANTY consult true experts is my advice instead of me

John T
 
John T, the problem is he did consult the "true experts" and they told him it couldn't/shouldn't be done.

Like you, I see no logical reason why it can't be done. An RV furnace mounts against the outside wall and is vented to pull combustion air from outside and exhaust combustion gases back outside. As an inanimate object I don't see how it could tell the difference.

Uninsulated 10x20 is an awful lot of area to heat with a small RV furnace though. If you aren't planning on being out there in extreme cold, it will probably work ok, but it will likely be running 100% of the time, and losing ground if the temperature is much below freezing. It might not be able to keep up.

Why would the insulation have to be removed in the spring? Why could it not be left in place? It would keep the place cooler in summer as well as warmer in winter.
 
Most RV furnaces now days are forced air and the fan will kill your battery really quick. The older gravity (no fan) RV heaters are getting pretty hard to find. Besides, I dont think those will have enough BTUs to work in your cabin without insulation. Even with insulation, that a pretty big cabin for one of those little gravity heaters.

They do make larger wall mounted or standing, direct vent heaters. Here is one: http://www.homedepot.com/p/Williams...-Cabinet-Mounted-Thermostat-3003622/100084617 Some of these types of units have optional fans, maybe you could run the fan when you first get to camp and then when things are comfortable shut it off, saving your battery power.
 
RV furnace with forced air and electronic
ignition uses 6 amps @ 12 volts when running. I
don't see that as big draw. If it runs 1/4 of
the time - that's equiv to 6 amps steady draw
for 6 hours for a 24 hour day. Any decent 120
AH deep-cycle battery can handle that load for
a night's worth of heat. At some point any
battery has to be recharged so a charge plan is
needed if using battery power for anything. A
few solar panels do the job fine. A pair of
120 watt panels would work fine.

Of course there's the unvented catalytic
heaters that give more heat inside the cabin
and use NO power. They also work nicely.

The difference between an RV furnace and a
household furnace is the type of safety
controls and efficiency. Household propane
furnaces are often 85% to 90% depending on
model and complexity. RV furnaces tend to be
80% efficient since it is assumed they are
being used in small confined areas and send out
a lot of heat out the chimney - while drawing
in some fresh air at the same time.
 
Any plan for power other then a generator? One 120 watt solar panel can power a 5 cubic foot refrigerator all year round. Put in four 120 watt panels and you can have your RV furnace, lights, refrigerator, and LCD TV and DVD player. Still need a backup system though if you get a week of no sun. A small gas engine hooked to an auto alternator makes a great battery charger. Much more efficient than using a factory made genset and charger .
 
(quoted from post at 13:16:01 11/14/14) RV furnace with forced air and electronic
ignition uses 6 amps @ 12 volts when running. I
don't see that as big draw. If it runs 1/4 of
the time - that's equiv to 6 amps steady draw
for 6 hours for a 24 hour day. Any decent 120
AH deep-cycle battery can handle that load for
a night's worth of heat. At some point any
battery has to be recharged so a charge plan is
needed if using battery power for anything. A
few solar panels do the job fine. A pair of
120 watt panels would work fine.


I disagree. First off, killing a battery overnight is completely unacceptable to me and thats why I mentioned it. If he kills a battery overnight, he is no better off than he is right now, needing to run a generator for half the day to recharge his battery. Solar panels are wonderful but in his stated usage, wont work. Cant count on the sun tomorrow so if its cloudy, its generator time for him and he already stated thats a no-go.

Second, you missed the requirements he has. 12x20 cabin with NO INSULATION. There is no way in gods green earth he is going to heat that at the 1/4 run time you are suggesting. 1/4 run time would be lucky to keep the pipes from freezing in an uninsulated cabin that size and ONLY if the pipes were surface mounted, all bets would be off if they went behind cabinets or something. Like I said, never going to work, NEVER at 1/4 run time.

The OP has a few unique problems: BTU, off grid and COPD. Without all three of legs holding the chair up, everything comes crashing down. COPD and asthma tells me it has to be direct vent. He loses some heat out the pipe and has more instalation hassle but it is what it is, and really, there is no point in going to a weekend cabin for enjoyment is you are going to get sick as soon as you get there. Off grid means limiting how much electric you use. Simple, you use electricity you either have to carry it in to the cabin sight or wait for it to be replaced by sun/wind/water. Replacing it via generator is what he has and its no-go so that rules out that. Cant count on sun for tomorrow so that leaves the generator as backup and we know thats out. So what does that leave? Carring in a good battery for every day of use? I dont think thats acceptable so thats out. To me, that leaves non-powered heating, or like I recomended, planning on using a fan only till the cabin heats up, then turn it off. I think thats a compromise that will work both in electric from battery and comfort. The last problem is simple BTUs. An unsulated cabin of that size will require a huge amount of BTUs to warm up when a person gets to the cabin and then a good number to maintain the heat at a comfortable level. Without more info, only the OP can guess how many BTUs will be needed but I think it will take more than most RV furnaces for the reasons I already stated, BUT a suitable room heater can easily be found in a wide range of BTUs. Alot of these room heaters have optional fans on them so thats why I recommended using the fan when you get there just to heat things up quickly but then quit using the fan to preserve the battery, letting the heater gravity heat the cabin.


(quoted from post at 13:16:01 11/14/14)
Of course there's the unvented catalytic
heaters that give more heat inside the cabin
and use NO power. They also work nicely.

Didnt you read the very first post, he has asthma and COPD. And you are recommending an unvented heater? Really? All I can say is wow.
 
When I had my past RV, it only had a single 100 Watt Solar Panel and if I recall I only had around 125 Amp Hours of battery storage THAT BATTERY COULD RUN MY FURNACE ALL NIGHT NO PROBLEM (depends on temp and operation time of course). Of course, if you dont have some stored battery energy the solar panel cant power the furnace at night lol so you need some battery storage. A 100 Watt Panel with a Charge Controller and a deep cycle battery could likely get you by.

John T
 
Opened the board at lunch and 16 replies! Lots of good ideas here, I was going to respond individually but with this many I’ll try to cover them in 1 for now.

As far as insulation, the interior is totally finished with exposed timbers and lacquered T&G pine, no exposed fasteners, so stapling up some rolled insulation is out. Thought about foam board type panels, but cost/summer storage would be an issue. Cabin has new vinyl low-E windows and insulated steel doors, and is fully caulked so it’s airtight.

I tried using a Mr. Heater Mh18B “indoor safe” 18k btu/hr propane heater with a window partially open for venting but ended up at the Dr’s office and 3 days on oxygen. Not so much the exhaust, but a mixture of particulates and condensation did me in. That’s why I was thinking direct vent. Temp outside was mid 30’s and it was steady 65 inside with heater on half throttle.

Solar is a future option, but for now I use 2 deep cycle batteries with a charger hooked to the generator (Honda EU2000I) and no problems keeping them at 75-100%. I hard-wired the cabin with 120v outlets, a ceiling fan and power for the flat screen, dvd, etc and have no issues with running it all night, the milkhouse heater just keeps the genny at ¾ to full load and runs out of fuel. Plus it’s not enough heat anyways. I was hoping that a RV heater would pull the load off the batteries, and the genny would run its normal 25% load to power the battery charger whenever I use the furnace.

Wood heat is out, I’m under STRICT instructions not to go anywhere that uses a wood stove. Might keep me warm, but in the AM I’d probably be dead. Asthma, COPD, onset TB and other problems keep my regular DR and my Pulmonologist on my butt every 3 months.

Sorry for being long winded (grin), but that’s why I was thinking RV furnace. Any more opinions/ideas are greatly appreciated!

Scott
 
Hey I'm not a doctor. I also don't know what
sort of "COPD" he has. I know someone that has
emphysema and has two unvented propane heaters
in his house and he also still smokes two packs
a day. To each his own.

In regard to being able to heat an uninsulated
cabin with a single 26K BTU input heater? I
never said he could. I just commented on the
differences between a furnace made for
residential use on 120 volts AC versus a
furnace made for RV use on 12 volts DC. Heating
a building with anything is a matter of how
cold it is out, how much heat loss it has, how
big it is, etc. No matter what the heat
source is.
 
I would consider your cabin to be about the size of a "week'ender" boat cabin. Lots of boaters simply use a 24,000 propane htr. for a week-end worth of heat.

Check-out the boat shops for a used cabin heater. Some are vented.

John,PA
 
I can tell you my specific experience with our cabin. Two story, 24' X 24' with a high gable roof. Downstairs is storage only. Beds are upstairs and that's the only area we heat. When I built the cabin it was pretty much just a "fair weather" abode. But I covered the entire outside with 1 1/2" foam board with steel siding or wood over it. So all the walls have 1 1/2" foam but the overhead high gable roof has NO insulation. When outside temps are in the 30s, the inside stays warm enough with a 30K "input" propane heater. Note the word "input." RV heaters are usually sold by BTU "output" and that is deceptive. An RV heater sold as a 40K BTU unit will have around 32K BTUs of heat to be used inside the cabin.
 
10 x 20 is only 200 square feet, an 8 x 24 camper is a small one at 240 sq ft. so why would it be an awful lot of area to heat? And campers have only a single pane glass in the windows and roof vents are just a thin piece of plastic? 3 vents to a 24' camper. You would loose more heat thru those roof vents and windows than he will thru his roof and he has insulated glass in the windows.
 
OK you guys. If you think a heater in a camper would kill a battery over night how do you think they can sell the campers? If it did that then there would be a lot of law suits over that and the camper makers would go out of bussiness. They make sure that there is plenty of battery power avaible so it does not do that. Key is properly sizing units.
 
RV propane furnace does not "kill" the battery overnight in an RV. That is pure nonsense. Forced-air RV propane furnace with electronic ignition draws 6 amps @ 12 volts when running. I've camped many nights in an RV in the winter with the propane furnace running, lights on, 32" LCD TV and DVD player used. All that on a single 120 AH deep-cycle battery.

Now in a space that's too big to heat and the furnace runs ALL the time (i.e. no cycling)?? Do the math. 6 amps for let's say 10 hours. A 120 amp-hour battery can supply 6 amps for 15 hours and be safe. So still works.
 
(quoted from post at 23:51:32 11/13/14) Howdy all,

Cabin isn't really a tool, but a lot of smart guys here.

12x20 timber frame cabin in the mountains, WAY off the grid but I use batteries, 12v lighting and such when I'm up there. Also use generator for power tools but run out of fuel after 5-6 hours if I try to run milkhouse heater. Also have to vent outside if I try propane heaters with my asthma and COPD.

Why could/couldn't I hook up a 12v 20k btu furnace from a RV? Maybe 30k btu? No insulation to speak of because interior is all beams and finished T&G, wife unit doesn't go up there in winter but If I insulate I'd have to pull it all out come spring which could get spendy.Ducting would be nice, and I've got several propane tanks. I've been told both yes and no by local RV shops, but figured I'd get a straight answer from you guys...

Scott in North Idaho

How did somebody go and build a nice camp and not spend a measly couple hundred bucks to insulate, install good windows and seal the air gaps?
A vented LP fireplace should do.
 
(quoted from post at 09:50:23 11/15/14) OK you guys. If you think a heater in a camper would kill a battery over night how do you think they can sell the campers? If it did that then there would be a lot of law suits over that and the camper makers would go out of bussiness. They make sure that there is plenty of battery power avaible so it does not do that. Key is properly sizing units.

Leroy, dont take my word for it, do some research and find out the facts for yourself. RV.net is a good resource. You will find that relying on battery power for heat when it funs a fan is a sure path to unhappiness (failure). Owner after owner after owner has been down this road, trying to milk out power beyond its capibilities. You simply cant store and produce power by shear will power, it simply dont work that way. You can try if you would like but that dont mean success for you any more than it has for the hundreds and thousands before you. The thing that is different here is this: if you choise to spend your own money chaising the elusive free energy dream, its your time and money you are gambling with (and losing). But when you recommend to others that something will work when it is already know to be the path to failure, you are throwing away other peoples money and time, money and time they may not have available. Thats a bad practice and shall we say, not nice.

Like I said, do some research, dont take my word for it. You will find piles of people disapointed at limited power for heating but what you wont find is tons of lawsuits and bankrupt camper companies in the disapointment wake.
 
(quoted from post at 11:07:49 11/15/14)Now in a space that's too big to heat and the furnace runs ALL the time (i.e. no cycling)?? Do the math. 6 amps for let's say 10 hours. A 120 amp-hour battery can supply 6 amps for 15 hours and be safe. So still works.

See, thats where we disagree. You feel that 15 hours is a success simply because it takes you technically "overnight". I feel thats a failure because what happens the next day? Unless you are only staying at the cabin for a single day, the next night turns into a very cold night. Remember, the OP already stated that running the generator for 5 hours uses up the gas he has so thats a no-go. Recharging with a solar panel is out because you cant count on having sun tomorrow so thats out. Bringing a fresh battery for every day you plan to stay at the cabin would technically work but who wants to do that? Im assuming but if a person dont want to pack in more than 5 hours worth of gas, they dont want to pack in about the same weight of batteries but only the OP can answer that.

So there ya have it, while you say "it works", I say if thats your plan A you better start working on plan B...
 
It would work but I do not think you need a forced air system that requires power. A vented propane space heater seems a better choice for a single room cabin with vaulted ceiling. The heat will move by convection and radiation.
 
You lost me. I already mentioned the need of a
way to replenish the batteries after being used
through a night. Reading comprehension issues??
 
Can't comment on why, or why not the guy did
not insulate. I can understand having the
inside done first so it can be used and now no
insulation can be added without a mess (to the
inside walls).

When I built my cabin in the NY Adirondacks -
my first plan was summer use only. Regardless,
I sheathed the outside with 1 1/2" foam polyiso
foam and then sided over it. Below grade has 2"
white foam insulation board. Not a great amount
of insulation but it DOES make a difference.

Wiring was tricky. Mostly wired for 12 volts DC
and had to pass inspection. Found out that
Square D type QO panels and breakers are one of
the few certified for AC and DC use. It all
passed by the way - before people start
grumbling about what they feel is wrong with
the wire-job. Needed DC rated breakers and
snap-switches for lights. No "silent" AC wall
switches allowed. Also - to pass NEC 2011
inspection - I had to install a sine-wave
inverter to make AC to power a few smoke alarms
just to make work during inspection. Found out
the cheaper mod-wave inverters do not work with
hard-wired AC smoke alarms.
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Other than needing a #6 bare copper from the panel ground bar over to the well casing. The electrical looks good to me.
I thought the young lad was fair haired?
 
(quoted from post at 08:09:21 11/16/14) You lost me. I already mentioned the need of a
way to replenish the batteries after being used
through a night. Reading comprehension issues??

Oh I get that you are lost and have reading comprehension issues. Why you just dont get it beyond me. I explain it... and you are lost. You recommend a solution the will land the OP in a [b:e9618bba7c]hospital[/b:e9618bba7c], I explain how thats a no-go... and you are lost. You try to justify your responce, I explain the problem and you are lost. You try to explain how something "works", I explain why that going to be a failure and you are lost. But yet, reading comprehension issues hold you back because again you come back reasserting your point... but still you are lost.

I get it. I Get It. I GET IT. For the love of God, I [i:e9618bba7c][b:e9618bba7c]GET IT[/b:e9618bba7c][/i:e9618bba7c]. You are lost. I GET IT. You could not make it any more clear how lost you are, trust me, I get it.

As for you admitted reading comprehension issues, dont be upset about it, admitting you have a problem is the first step and there is help available in most every community in this country. Even a ESL could help you, if not directly, they could send you to the right place. I wish you luck, lord knows you are going to need it.
 

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