Heating a VERY TINY off grid cabin

[fendruadin]

Hi there! I'm new to the forum, and determined to finally build my very tiny off grid cabin in 2019.

I've got land, and a spot picked out, and a basic floor plan I like. A couple friends with construction experience are going to help me "value engineer" my design and put together building plans in the next couple weeks. Meanwhile, I'm considering heating options, and I need a little help.

The footprint of the cabin will be a mere 8' by 16', with a small loft big enough to hold a queen size mattress and a bedside table. I would like the cabin to be insulated, but we may not get that far this year. It will have several large windows.

Most of the floor plan is open, with a small room for a composting toilet and wash tub, which doesn't have to be heated necessarily.

No plumbing and at most a small amount of wiring (I may wire for lights though, and eventually install a small amount of solar). Water will come from rain catchment and/or hauled up from the spring-fed creek at the bottom of the hill and/or carried in as bottled water for drinking.

I want a small cooktop and a heater.

I'll be using it year-round, but only as a get-away. It's not a permanent dwelling, so I can make some compromises. It's located in a relatively temperate climate, in the foothills of the Appalachians of North Carolina, where it snows most winters, but the snow doesn't generally stay more than a few days at a time. Temps in the 20s are common at night, but not often much below, and days are usually at least in the 30s and 40s if not above.

In that very tiny amount of space, I also want one wall that is about 2/3 window, as it looks down over a view that I want access to; a couch that pulls out into a second bed; countertop space; a wash basin for dishes and hand-washing; some cabinets and cupboards for storage.

Somehow, I still have to fit in heat.

Given all of those criteria, what would you install and/or use for heat?

I've read conflicting views on propane. I don't mind buying tanks, so that's not an issue for me. But I've read that even the vented propane heaters can't be run at night because of the risk of carbon monoxide poisoning. Given that I won't have electricity, a CO monitor may not be an option.

But burning wood takes up a lot of space and time and effort I'd rather spend curled up with a book or out talking to my trees.

I do sometimes camp in winter and have good winter camping gear, so it might be all right with me if it gets cold overnight but... honestly... I'd RATHER it be warm all night long, or at least not frigid.

Given the very tiny size of my cabin and the relative moderateness of my climate, is it possible I could get away with a propane heater and insulation; run it before bedtime to warm the place; and then turn it off and be reasonably toasty overnight? Even if I'm sleeping alone (which sometimes I am, and sometimes I ain't)?

Or am I better off investing in something that will burn all night even if it means installing a wood burner? Or is it really truly okay to run a vented propane heater all night?

And, in the midst of all that, what are my best options for cooking? Would I be better off combining a wood burning stove and heater rather than a propane cook top? Or am I better off with a propane heater AND a propane cooktop? Or better to do one as propane and the heat as wood? Or???

I'm open to all options. Obviously, I'd rather not spend a mint on the heat, but if I have to I'll figure out how to do it.

Thanks in advance for all your ideas and experiences!

[Mike 870]

I like propane in small spaces.  Something like this?:

https://www.amazon.com/Dickinson-Marine-Newport-Propane-Fireplace/dp/B01HU3GR3I/ref=asc_df_B01HU3GR3I/?tag=hyprod-20&linkCode=df0&hvadid=309770216338&hvpos=1o1&hvnetw=g&hvrand=13839480021847619660&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9015823&hvtargid=pla-583636900689&psc=1

It would work well in 8 x 16 with insulation, it can operate without the fan on, without electricity.  If you want something less expensive, there are many vented propane heaters like this that will do the same thing, run with no elec, but are just less "pretty",  basically square wall mounted heater boxes.

[MountainDon]

 
I would use a direct vent propane heater. For such a small structure wood stove heat is, IMO, impractical. Most will require too much clearance space around the back, sides and front to leave much usable space for you.  Proper installation means placing the exhaust vent the correct distances from windows, doors, etc to make it next to impossible for the exhaust gases to enter the building. The installation instructions for any approved direct vent heater will have all the proper clearances illustrated.

This link is to an example installation brochure. See page 6.   You may have trouble finding a small enough propane wall heater.

Another issue may be finding a heater that does not require electrical power for a fan. Many wall mount heaters are intended to be used on AC power. We have one that is built to be able to be used with no power. It is no longer made so I have not provided a link.

An RV furnace may be an alternative, though it will not be approved for use in a conventional building. Those also have a power need, although 12 volt DC instead of 120 VAC. Their design makes then inoperative without a source of 12 VDC power.

There are small wood burner stove designed for marine use. They tend to be pricey and are small enough that you would likely have to restoke the fire at least once, maybe twice overnight. Sorry, I have not any bookmarks to pass along.

I know someone who uses a Dickenson marine heater that operates on propane. He has it in a 7x14 utility cargo trailer. It would probably be usable. I don't think it requires any power, but it has been a while since I saw it so am not sure of that.


For cooking I'd also recommend propane and I would make it portable so in warm weather you could place it outside. A small space will get very hot quickly if you cook inside in warm or hot weather.

[MountainDon]

There. Mike posted a link to the same stove. Must be a good idea 

[Mike 870]

Also, here is an under floor mount version of my propane furnace.  Advantages are you can get creative with space and where you mount it.  I used my version because it could be put it under a bed, and not take up wall space.  Drawbacks are that it needs DC power, kinda hogs, and is loud if not sound insulated.  They are more efficient on propane, roughly 92%.   

https://www.propexheatsource.com/heaters/hs2211-furnace/ - under mount version

https://youtu.be/NI405OEvduY - video of my install

*edit, great minds think alike Mtn Don!

[MountainDon]

Dang!  Mike did it again. The Propex is a great heater if you have 12 VDC.  Under the floor, out of the way, quiet if insulated...    I almost put one in our converted cargo trailer.  I made my own heating system using the heated water from the RV water heater and a small oil cooler radiator with 12 VDC muffin fans and a recirculation pump. The trailer is well insulated and that works well for us since we want hot water anyways.

[Mike 870]

haha thats too funny!

[fendruadin]

Ahhh! Thank you SO MUCH for these fast and detailed responses.

Okay, so I'm looking at propane, then. That makes sense and quite honestly makes me happy. I don't want to burn wood for all kinds of reasons.

I also do not want to have to rely on any electricity for heat, as hauling a camper battery up the hill is going to be a PITA. A fan that runs on a couple D batteries might be all right, but anything with a bigger pull than that is going to be a constant trouble to me. The site is somewhat remote and steep...

I love the look of the Dickinson. So it will in fact be safe to run at night while sleeping? I kept seeing articles that said even a vented propane heater has to be turned off at night, but I wonder if the authors were confusing them with ventless?

Also, is it possible to get a CO detector that doesn't require plugging in to power?

So, I'm looking seriously at the Dickinson. What do you all think of this?

https://www.go2marine.com/product/83100F/cozy-cabin-heater-propane-boat-heater.html?WT.srch=1&WT.mc_id=gb1&utm_source=googlebase&utm_medium=productfeed&utm_campaign=googleshopping&gclid=Cj0KCQiAmuHhBRD0ARIsAFWyPwiDD1AMKz3pEeiqCKD4AwvfoE0EslKegGYKRC12PVykM7iSi4q8OOAaAhWOEALw_wcB

It's gorgeous and tiny and inexpensive (relatively speaking) and probably sufficient from an ability to heat standpoint, given the size of my space and the mildness of my  climate. But can you tell from looking at it whether it requires electricity? And is it vented?

I can't tell you how much I appreciate all these replies. Y'all are the best. Thank you.

[fendruadin]

Whoops. Okay. I can read, lol. The heater I linked IS vented. Just trying to figure out if it requires any sort of electric power.

[fendruadin]

And it has a cooktop!

But thank you for the suggestion to have a portable cooktop too, for summer. Mostly, I'll be heating things like tea and coffee... I don't really cook... lol. Eating is either canned stuff, cheese and salami and fruit, or something heated over an open outdoor fire. But I suppose every once in a while it's nice to warm up a bowl of soup... and others who are with me might want to cook...

[MountainDon]

I may be wrong but I think the Cozy uses interior air for combustion, otherwise it would not have an oxygen depletion sensor and shutoff. I think the P-series, there is also a bigger one, uses exterior air... but read up on that.


We have a CO monitor that can operate on 120 VAC as well as batteries.

[fendruadin]

It does use internal air for combustion, and now I'm confused. What is the venting for if it's pulling internal air for combustion?

[Mike 870]

There is combustion air, used for the reaction of burning, and then there is the byproduct of the combustion, the exhaust air.  Ventless heaters simply vent to the interior.  Many people use them, I have never been comfortable with the idea.  They also produce humidity which can be an issue.  I have battery operated C02 monitors, I got them at Home Depot.

[fendruadin]

Thank you! I'm so glad I'm doing this research in advance so I can plan around the right heater. I really appreciate your patience with me.

So, it looks like the Cozy Cabin is out. Based on your feedback and also based on the reviews I'm seeing in some sailing forums. And in addition to everything else, I do NOT want to add humidity to the environment. It's already a rather damp environment (woods, North Carolina) and I don't need anything contributing to that.

So the P9000 then, maybe. Thank you so much!

[NathanS]

Looks like you have gotten some good advice.

One alternative idea are marine wood stoves, they take up almost no space and won't cook you out at night. People will put them in their RV's.

https://cubicminiwoodstoves.com/

[Dave Sparks]

If you have a resource of good firewood (Oak) I would find a way to install a zero clearance wood stove.
They make some small ones and there is nothing like being as warm as you want without opening your wallet.

It is cheaper than going to the gym and very high quality heat. You do have to have the wood or a inexpensive source of it.

I have a tree on the road that is blocking it and that is where I am going next

[fendruadin]

Thank you for these additional suggestions! I like the idea of wood heat for dehumidifying. Humidity is a HUGE issue around these parts, and the last thing I need is mold growth in my cabin. I didn't realize there were wood heaters with zero clearance. WOW.

I can have firewood EASILY. The site is in the woods, and 24 acres of it belongs to me. It's also in the country where you can buy it by the truckload for $25 or less.

I'm going to check the links out. Thank you!

[Dave Sparks]

Home Depot woodstove

https://www.homedepot.com/p/Pleasant-Hearth-1-200-sq-ft-EPA-Certified-Wood-Burning-Stove-with-Small-Blower-HWS-224172MH/203883464?cm_mmc=Shopping%7CG%7CBase%7CD28I%7C28-20_FIREPLACE%7CNA%7CPLA%7CFixed%7c71700000041073829%7c58700004389677714%7c92700036924273665&gclid=Cj0KCQiAhKviBRCNARIsAAGZ7CebfyiOM57_ddBF5S4Ok7rtvy70UJtq4e9HbDSZRjyDJTZBfL_moLAaAoDpEALw_wcB&gclsrc=aw.ds

Also look and see what Osburn has. Mine has had nothing done to it in over 15 years.

[JRR]

Now the thoughts from, very deep, left field....

If the cabin is to be very small and very tight construction, I would always be concerned about having any combustion inside while I sleep.  Here it comes!:  (I have been a recent convert to tank-less hot water heaters.  I helped son-in-law convert from electric-tank to gas-tank-less.  Passed the city inspection.  Space and energy saver.  Instant response!  And I read that RV tankless hot water heaters require no electrical input.)   So imagine such an propane RV heater mounted on the outside wall of the cabin with a protective cover.   Construct a loop of PEX tubing that connects heating floor coil with heater.   Include an atmospheric vent in the PEX loop to take care of start-up bubbles and expansion.  Fill loop with engine styled coolant.  Now you are ready to go!

Oh wait, I forgot the recirculating pump!  Hmnnn.   You could splice in a cast-iron bodied barrel (manual crank) pump.  They are good for up to 140 F.  When the chill comes, just spend the crank handle a few turns .   Or ....

(You'll have to make separate stove-top provisions, but one is less likely to leave the stove top on while sleeping. )

[busted knuckles]

I have this propane heater,

https://www.go2marine.com/product/83100F/cozy-cabin-heater-propane-boat-heater.html?WT.srch=1&WT.mc_id=gb1&utm_source=googlebase&utm_medium=productfeed&utm_campaign=googleshopping&gclid=Cj0KCQiAmuHhBRD0ARIsAFWyPwiDD1AMKz3pEeiqCKD4AwvfoE0EslKegGYKRC12PVykM7iSi4q8OOAaAhWOEALw_wcB

I have been using it in a 12x8' cabin for 3 winters now. No issues, I don't find it to produce any moisture, it is vented. I am very happy with it. A 20 lb tank will last about 10 days, at about 3 or 4 hours a day. I do use a battery powered co2 alarm. It has never gone off.