Off grid cabin new wood stove recommendations?

[tom80]

Hello all,

I have been reading posts on here for a while but can't seem to decide and need some advice. We have a 24x26 cabin in Quebec, 1 bedroom on main floor, cathedral ceiling (half of it is open loft, where we actually sleep). So 624 sq ft + 1/2 open loft = total around 936 sq ft. It is a recent build and well insulated, a part from the floor which is a concrete slab.
It is off grid and the only source of heating is propane stove (Napoleon GDS28) which puts out only 22,600 BTU's. It's a weekend cabin and in the winter it gets to -30F at times so waiting 24 hours for the temperature inside to go from 23F to 60F is a pain. And it won't get any warmer than 65-70F when it's -30F out

I was looking at getting a wood stove instead, since the heat rises easily and we sleep upstairs so it's considerably warmer upstairs than downstairs but i can always open the loft window.
I am considering the Osburn 950 (same specs as Drolet escape 1200/Deco Nano/Spark II) which has a 1.55ft box and up to 45,000BTU's. It should do fine not cooking us out in the shoulder season and i'd really have to fill it in the winter to pump some heat but not sure if it will go up to 6-7 hours of actual heat in the freezing cold days or it's really 5 hrs as the manufacture states (the box has a similar depth to TN20/Super27 but 2 inches less width)

My next considerations would be the PE Super, TN20 or Jotul F45 (which i find a little pricey but fine piece of stove)
I will prefer the N/S loading, overnight burns if possible!
Currently the Propane stove goes through the outside wall so i can use that hole once i sell the propane stove but i prefer that the wood stove goes straight up through the roof (a good 16-20 feet or so) and I'll patch the hole from the propane. I will get it professionally installed.

Do you think the Super/TN20/Jotul F45 will cook us out during fall and spring? I don't want to use any space heaters, the propane smells badly everytime i light it and we're trying to eliminate it all together. The wood stove would be the only heat source.
I know i need a lot of BTU's to get the place warmed up from freezing cold when we get there but would the super 27/TN20/F45 be too much heat during sleep and during fall/spring?

My profile picture is the actual cabin so you get an idea
Let me know what you guys think!
Will the Osburn 950 do fine 95% of the time or it's just not enough?

 

[bholler]

If it is an option at all I'm would keep the propane stove and get a medium to large woodstove to work with it.

 

[Ashful]

What are you doing to insulate that floor? If exposed concrete, it may hold some advantage in keeping the place warm when you're away for weeks with no heat. But you're going to be fighting it when trying to heat the place, as you've already seen. My first priority would be nicely-insulated carpet or flooring, to hide as much of that concrete, as possible.

Most of us can figure on roughly 5 BTU per sq.ft. per HDD, but your better-insulated place may be 4 BTU/ft2 or better. So, if your -30F nights correlate with +10F days, you'd be at 74 HDD, or 266k BTU. That's about what it would take to heat a 1200 sq.ft. place at 5 BTU/ft2 in many of our more temperate 20F dead-of-winter averages. Point is... 900 ft2 is small, but you can handle more stove than most, due to the high HDD demand.

Of course, depending on how much concrete is exposed, my estimate for your demand could be off in the wrong direction. It sure would be nice to get a sense of your heat loss. Are you able to measure temperature drop for a given outside temperature, in the hours after shutting off your current heat source? That would give you some rough numbers to use for estimates.

bholler's suggestion is excellent, it's exactly what I do for my (albeit, much higher) heating needs. This lets you just load the stove 2 or 3 times per day, whatever suits your schedule best, and let the central heating modulate the final comfort atop that. You'll burn very little propane, due to the stove carrying the majority of the load, and also avoid the frustrations of trying to moderate temperature with the stove alone.

If you're going to try to swing it on stove alone, and based on your place being uniquely small, uniquely well-insulated (or not), and in a climate in which few of us have real heating experience, I'd say you're going to want some better heat loss data, before choosing the stove.

 

[Nate R]

The slab...is it completely uninsulated, or insulated on the sides, or all around?

I have a relative with a 24x32 cabin that is now fairly well insulated, and also has a loft that's 1/3-1/2 of the depth. They are on a slab which is NOT insulated at all. They use an Osburn, but I don't know what size/model off the top of my head, I can look soon.. That said, before insulation, they installed a propane furnace that's probably 50K BTU as well... so they can get the air temp up quickly at first. After that, they coast on the wood stove easily.

My own place is smaller, 520 SF, on a mostly insulated slab, no loft. I'm using a small Jotul F100, (0.85 CF firebox), but also am on grid and have electric heat to supplement. I find no matter what, it will take BTUs to get that slab up to temp. That also means that the "heat losss" calcs are tough.... as over a few hours things move more slowly up OR down with the tempering effect of that slab. It takes time for that slab to slow down how fast it's robbing heat from the air. OTOH, once it's warm, it's not cooling down too quickly.
Here's a graph of temps at my 520SF place over a weekend recently... (Outdoor temps, indoor, and the slab temp at a 2" depth, about 2 feet from the outside wall).... Each vertical line is 6 hours.... you can see it really takes about 24 hours before the slab levels off how much heat it's sucking. So you want a lot of BTUs for that first night and next morning, but after that, I find my heat needs drop considerably...



I 2nd the vote for a medium wood stove and keep the propane for helping the initial warm-up on cold days. Happy to find out what model Osburn my relative is using if that's helpful..

 

[EatenByLimestone]

What temp are you keeping the place when you aren’t there? If it’s the same as outside, you’re going to need a much larger stove than if you keep it at a set temp above freezing.

I have a 16x29 cabin in the Adirondack Mtns and run a T5 in it. I see -23 and strong windchill sometimes and when that weather is present, sometime you just can’t get warm temps. The wind strips the temp as soon as the stove throws it out.

I don’t like to use the stove over 30F or so as it’s so oversized and I can easily run an electric heater if needed. When it’s cold and I walk into a very cold cabin I use propane and electric heaters to help warm the place up quickly.

 

[begreen]

Considering it is off-grid, go larger. It takes many times more BTUs to warm up the mass of a building than it does to maintain comfort once everything has temperature equalized. If you are only there for a weekend it may take the entire time for this to happen. Consider the highly radiant Drolet Austral to accelerate this process. It will burn fine with a partial load of fuel once the place gets above 15ºC. Or at least go up to the Drolet Escape 1800.

 

[tom80]

What are you doing to insulate that floor? If exposed concrete, it may hold some advantage in keeping the place warm when you're away for weeks with no heat. But you're going to be fighting it when trying to heat the place, as you've already seen. My first priority would be nicely-insulated carpet or flooring, to hide as much of that concrete, as possible.

Most of us can figure on roughly 5 BTU per sq.ft. per HDD, but your better-insulated place may be 4 BTU/ft2 or better. So, if your -30F nights correlate with +10F days, you'd be at 74 HDD, or 266k BTU. That's about what it would take to heat a 1200 sq.ft. place at 5 BTU/ft2 in many of our more temperate 20F dead-of-winter averages. Point is... 900 ft2 is small, but you can handle more stove than most, due to the high HDD demand.

Of course, depending on how much concrete is exposed, my estimate for your demand could be off in the wrong direction. It sure would be nice to get a sense of your heat loss. Are you able to measure temperature drop for a given outside temperature, in the hours after shutting off your current heat source? That would give you some rough numbers to use for estimates.

bholler's suggestion is excellent, it's exactly what I do for my (albeit, much higher) heating needs. This lets you just load the stove 2 or 3 times per day, whatever suits your schedule best, and let the central heating modulate the final comfort atop that. You'll burn very little propane, due to the stove carrying the majority of the load, and also avoid the frustrations of trying to moderate temperature with the stove alone.

If you're going to try to swing it on stove alone, and based on your place being uniquely small, uniquely well-insulated (or not), and in a climate in which few of us have real heating experience, I'd say you're going to want some better heat loss data, before choosing the stove.

Thanks a lot bholler and Ashful that is something I will have to consider. That is a very good point, I will try to get a measurement of heat loss once the stove is off to get a better understanding of how much heat I loose.

 

[begreen]

My shop had an exposed concrete floor. It was very hard to heat. I put down simple, interlocking, .5", foam flooring and the difference is day and night. I can easily heat the insulated space now with a regular electric space heater. They have been in there for 8 yrs now and have stood up better than expected.

https://www.lowes.com/pd/Shock-Athletic-6-pack-24-in-x-24-in-x-12mm-Dark-Gray-Gym-Flooring/5001944001

 

[tom80]

The slab...is it completely uninsulated, or insulated on the sides, or all around?

I have a relative with a 24x32 cabin that is now fairly well insulated, and also has a loft that's 1/3-1/2 of the depth. They are on a slab which is NOT insulated at all. They use an Osburn, but I don't know what size/model off the top of my head, I can look soon.. That said, before insulation, they installed a propane furnace that's probably 50K BTU as well... so they can get the air temp up quickly at first. After that, they coast on the wood stove easily.

My own place is smaller, 520 SF, on a mostly insulated slab, no loft. I'm using a small Jotul F100, (0.85 CF firebox), but also am on grid and have electric heat to supplement. I find no matter what, it will take BTUs to get that slab up to temp. That also means that the "heat losss" calcs are tough.... as over a few hours things move more slowly up OR down with the tempering effect of that slab. It takes time for that slab to slow down how fast it's robbing heat from the air. OTOH, once it's warm, it's not cooling down too quickly.
Here's a graph of temps at my 520SF place over a weekend recently... (Outdoor temps, indoor, and the slab temp at a 2" depth, about 2 feet from the outside wall).... Each vertical line is 6 hours.... you can see it really takes about 24 hours before the slab levels off how much heat it's sucking. So you want a lot of BTUs for that first night and next morning, but after that, I find my heat needs drop considerably...



I 2nd the vote for a medium wood stove and keep the propane for helping the initial warm-up on cold days. Happy to find out what model Osburn my relative is using if that's helpful..

Nate, i am not sure if it is insulated under (if that's even possible.. we bought it a few years after it was built). I know it's coated with epoxy on top of the slab but definetly no insulation on top of the slab. Some carpets is not a bad idea.., in the summer it does cool the house down a little so that's a plus. Do you think a Jotul F45 is a better medium stove due to the cast iron and it will bring the temperatures up to speed it will regulate the heat spikes better? The graph is really helpful by the way! I would be curious to know what model your relative is using

thanks

 

[tom80]

What temp are you keeping the place when you aren’t there? If it’s the same as outside, you’re going to need a much larger stove than if you keep it at a set temp above freezing.

I have a 16x29 cabin in the Adirondack Mtns and run a T5 in it. I see -23 and strong windchill sometimes and when that weather is present, sometime you just can’t get warm temps. The wind strips the temp as soon as the stove throws it out.

I don’t like to use the stove over 30F or so as it’s so oversized and I can easily run an electric heater if needed. When it’s cold and I walk into a very cold cabin I use propane and electric heaters to help warm the place up quickly.

Hi,
the temps inside are same as outside when i get there friday so yeah i think i will need a 2.0 cbf firebox i think. Thanks!

 

[tom80]

My shop had an exposed concrete floor. It was very hard to heat. I put down simple, interlocking, .5", foam flooring and the difference is day and night. I can easily heat the insulated space now with a regular electric space heater.

https://www.lowes.com/pd/Shock-Athletic-6-pack-24-in-x-24-in-x-12mm-Dark-Gray-Gym-Flooring/5001944001

Hi begreen,

I appreciate your input, i will look into the interlocking foam flooring for sure. Do you guys think a PE Super 27 should do the job? I heard great thinks about it on this forum and it shouldn't disappoint.. if i can get the place up to 60F in 4-6 hours I'll be happy, then to another 75F won't take much longer

 

[begreen]

The Super is a wonderful stove and a nice performer, but for short heat I think you will need more horsepower if it's below zero ºF outside. If just for weekend heating I'd go for the larger, Drolet Austral, assuming clearances can be met. This is a very radiant stove (no side shielding). It still takes a lot of BTUs to take the mass of the place from 60-75º. The Drolet Escape 1800 is a bit smaller but it should also work.

That said, I think you will find that insulating the floor will make a large difference and then the Super may work in conjunction with the propane heater. The Super will provide a good overnight burn too.

 

[EatenByLimestone]

I’m only a single story, so you’ll want to go from super to summit.

You may still want to use supplementary heat to give the thermal mass the kick it needs to get to temp in a reasonable time.

 

[bholler]

Hi,
the temps inside are same as outside when i get there friday so yeah i think i will need a 2.0 cbf firebox i think. Thanks!

I think you need bigger to bring the mass up from cold.

 

[tom80]

Thanks a lot for all your great recommendations guys! I think I'm on a good path now

 

[Nate R]

I would be curious to know what model your relative is using

Hoping I can stop by their place this weekend when I'm in the area. I'll let you know.

 

[begreen]

Besides the cold floor, the other factor that make this challenge is the lack of a ceiling fan. Without one, the hot air will stratify up at the ceiling peak. It could be 80º in the loft and 50º chest level on the main floor and 30º at the floor. A stirling engine fan might be helpful, especially if connected to a manual ceiling fan like they used to use in India in the days of the Raj. Or maybe a battery-powered DC fan?

Or... a weight driven one?

Non electric ceiling fans- belt driven- perpetual motion (urban gardening forum at permies)

Prior to electric, ceiling fans were belt driven. Has anyone seen any plans on how to make one of these out of easy to come by recycled parts?.

permies.com

 

[tom80]

Besides the cold floor, the other factor that make this challenge is the lack of a ceiling fan. Without one, the hot air will stratify up at the ceiling peak. It could be 80º in the loft and 50º chest level on the main floor and 30º at the floor. A stirling engine fan might be helpful, especially if connected to a manual ceiling fan like they used to use in India in the days of the Raj. Or maybe a battery-powered DC fan?

Or... a weight driven one?

Non electric ceiling fans- belt driven- perpetual motion (urban gardening forum at permies)

Prior to electric, ceiling fans were belt driven. Has anyone seen any plans on how to make one of these out of easy to come by recycled parts?.

permies.com

That could work, i'll consider the stirling fan. I was thinking of getting one of those heat powered eco wood stove fans that i can put on top of the stove and i would point it towards under the loft (kind of away from the open space, more toward the bedroom/bathroom at the end of the main floor) so it should help reduce the heat rise a little..

 

[showrguy]

That could work, i'll consider the stirling fan. I was thinking of getting one of those heat powered eco wood stove fans that i can put on top of the stove and i would point it towards under the loft (kind of away from the open space, more toward the bedroom/bathroom at the end of the main floor) so it should help reduce the heat rise a little..

Those little fans move VERY LITTLE air off/away from the stove… jus sayin !!

 

[begreen]

Those little fans move VERY LITTLE air off/away from the stove… jus sayin !!

Yes, It might take 2 or 3, that's why I suggested the stirling with bigger blades and more air moved.

 

[showrguy]

Yes, It might take 2 or 3, that's why I suggested the stirling with bigger blades and more air moved.

I got both, and neither one does much for air movement..
I call em a conversation piece when folks ask about em..

 

[xman23]

As you said a major issue is arriving to a cold cabin. I did this for years, The cabin's thermostat to electric baseboard was 45 all the time. When we arrive, 45 to 60 was about 3 degrees an hour. After years of this, I built a controller to operate 4 electric baseboards from a 7 day programmable thermostat. It is set to switch to 65 on Friday at 11AM. Its been great, about 60 when we get there. Issue with this is when we don't arrive the cabin is brought up to 60 until Friday at 7PM, when it goes back to 45. I now have wifi, so I can control stuff with remote switches. I need to change out my thermostat to a wifi type. This is another thread, "remote control devices".

But...... you being off the grid, can you do any of this? I assume your maintaining a cabin temp when you're not there with the propane. If you know when you're going there, a programmable thermostat can work.

As to your stove, I wouldn't be concerned with too big of a stove. You can run them with a small load just fine. Let me qualify that to non cat stoves that I have. Cats are somewhat different, others can comment. With single digit and sub 0 temps you need a full size stove. When we are there, my cabin 28 X 36 is being heated only with a Jotul Oslo. It can easily maintain any house temp we ask for, 70+ at -15F for days. With a little practice, it becomes second nature running a stove and maintaining a comfortable house.

Tom

 

[joop]

problem here is its damp ,i wood go as big as u can and build smaller fires when u need to crank it its there

 

[joop]

a good1800 sqft and just play with it as season changes

 

[begreen]

Another budget stove with a big heart is the Englander 32-NC. SBI now owns Englander, so that might be an option if available. I think they used to be sold by Canadian Tire stores.