Stove sizing

[Gorben82]

Hello,

I am building a cabin in WV appalachia. The cabin is 16x24 (380 sqft) with 9/12 roof pitch and vaulted ceiling around 15ft at peak and a loft (16x10 away from stove). Insulation is r13 all around and r10 on the floor. This is a week end cabin, I am expecting a lot of cold starts in the 30s.

My wife does not deal well with cold temperature and if I am unable to warm the place in a reasonable amount of time, this will be a deal breaker. I never really had a wood stove before so I am not sure what to expect.

I like the drolet nano/1200. Price point would work well but I am unsure if it will be big enough. Would a cast iron stove like the jotul F 602 be better? Drolet also has a 1800 that seems quite a bit bigger than the 1200. Would that be better? My goal would be to make the place confortable (60+) within the hour. Ideally I would like to keep the stove <$1500.

Thanks for your help!

 

[begreen]

The goal is somewhat unrealistic unless the cabin has been kept at 50º or so while empty. It's good to think larger for the stove. It takes a lot of extra BTUs to bring up not only the room temp, but also to heat up the mass of the building and its contents. A wood stove could take 3-6 hrs to do this. The first 30 minutes is just warming up the stove enough to radiate heat. Another issue is feeding cycles. A small firebox is going to need to be re-fed every 2-3 hrs when pushed for heat. This is where a larger firebox helps. However, once the place has warmed up there is a possibility of overshoot and the place getting too hot due to the small space being heated. The typical remedy is to open a door or window, but that may not satisfy her.

The best compromise is to have an auxiliary source of heat for the quick blast but one that can be shut off quickly. Electric or propane heaters can do this in conjunction with a smaller stove. Otherwise, get a stove in the ~2 cu ft range. The True North TN20 is worth considering. It heats up quickly and loads N/S for full capacity loading.

FWIW, my wife is a trooper, but does not deal with the cold either. Regardless of choice, be sure to invest in an electric blanket so that the bed is fully warmed up.

 

[Gorben82]

Oh wow, thanks for your reply. I did not realize that it would take so long. I like the idea of a heating blanket. That would definitely help.

When you say 3-6 hrs, is it with the drolet nano/1200 with 45000 BTU or the 1800 with 70000 BTU?

 

[EatenByLimestone]

Ok, I have a cabin that’s a similar size to yours. 16x29. I frequently come up in winter and heat the cabin from 10F, sometimes in the negatives, etc. I have a 2cu ft stove. It has a steel box, and cast iron surround to dull the searing heat that can come out of it. After the heat up, it’s tough to keep the place from being a sweatbox if it’s not under 30. Don’t rely on the stove alone if you want a happy wife.

So, if you’re not going to be much under 30 as an outside temperature , I’d stay smaller than 2 cu ft.

I use multiple heaters to warm my place up. When I walk into a cold cabin I plug in some electric heaters, I have every outlet on its own circuit so I can run a number of them if need be, and I turn on a propane sunflower heater that runs on a 20lb propane tank. I think they put out 15k btu. In a pinch, I’ve also fired up the propane cooking stove. Each burner adds to the heat. It takes a lot of energy to warm a cold structure in a relatively fast time.

A word of warning with the ventless propane. It puts a lot of water into the air. If it’s real cold, that water will condense on the walls. I don’t think it’ll happen at 30, but it does at -20, lol. Be aware you’re not exhausting combustion products outside too. It all stays in there with you.

 

[EatenByLimestone]

Oh wow, thanks for your reply. I did not realize that it would take so long. I like the idea of a heating blanket. That would definitely help.

When you say 3-6 hrs, is it with the drolet nano/1200 with 45000 BTU or the 1800 with 70000 BTU?

The more steel you have to warm up to temperature, the longer it’ll take before it starts pumping heat into the room.

The kicker to that is the smaller the stove is, the more often you have to load it while you want to sleep.

 

[begreen]

When you say 3-6 hrs, is it with the drolet nano/1200 with 45000 BTU or the 1800 with 70000 BTU?

I was thinking with the larger stove working solo to heat up the place. After an hour, you wife may be convinced to come out of the car but it may take another 2 hrs. before she takes off her parka. At that point, the air will be warmed up, but if you sit on a sofa it may still feel cold. That's what I mean by heating up the mass of the place.

A radiant stove with no shielding will heat up adjacent surfaces faster, but a convective stove like EBL has will be more comfortable once the place has warmed up.

 

[Gorben82]

Awesome, thanks a lot. That's exactly what I wanted to know! I want to be able to go there when it's really cold, but realistically it does not get THAT cold where I am. Looking at the monthly average in January, daytime is in the 40s and night in the 20s. I want to size the stove properly so we can still use it in the shoulder months when we only need a quick fire at night.

Having multiple source of heat makes sense. I can get the drolet spark II and a 80000 BTU convection LP heater for when we arrive.

I see that the small drolet as a maximum burn time of 5 hrs.... I guess I'll have to also invest in a good comforter .

I was thinking of installing the stove with a fresh air intake. I can see the benefit for the when the stove is going strong, but when it dies out... wouldn't the cold air from outside speed up the chilling process? Can I install a damper on the fresh air intake to block air coming in at night?

 

[EatenByLimestone]

In 40 degree temps, even 30 degree temps, I’m more likely to just run an electric space heater than start the stove. Your small stove and higher ceilings will change that equation quite a bit, but 40s aren’t all that uncomfortable. It’s hoodie weather.

 

[kborndale]

In 40 degree temps, even 30 degree temps, I’m more likely to just run an electric space heater than start the stove. Your small stove and higher ceilings will change that equation quite a bit, but 40s aren’t all that uncomfortable. It’s hoodie weather.

Takes a long time to warm up a cold cabin with space heaters, this isn't for a house that is already warm, it's for a cabin that's going to be cold when they arrive.

 

[EatenByLimestone]

Right. This is what I do for my cabin in the Adirondacks .

Once heated up, my stove will push you out of the room above 30 or so. You need lots of energy to warm the place up, but once there it doesn’t take much.

I should also note that I have extra 2”thick firebrick on the floor of my firebox to allow me to run smaller fires with a clean burn.

 

[kborndale]

I know the OP was not trying to spend a lot of money but this situation is perfect for a cat stove. You can get a large enough one to really crank up the heat when it's needed upon arrival, but can then cruise along low and slow once the place is heated up.

 

[Gorben82]

In 40 degree temps, even 30 degree temps, I’m more likely to just run an electric space heater than start the stove. Your small stove and higher ceilings will change that equation quite a bit, but 40s aren’t all that uncomfortable. It’s hoodie weather.

The cabin is off the grid so the electric heaters are probably not going to cut it. I can and will definitely get some LP heaters

Right. This is what I do for my cabin in the Adirondacks .

Once heated up, my stove will push you out of the room above 30 or so. You need lots of energy to warm the place up, but once there it doesn’t take much.

I should also note that I have extra 2”thick firebrick on the floor of my firebox to allow me to run smaller fires with a clean burn.

That’s exactly what I was afraid of. From all the calculation I made, it looks like I can maintain the temperature with 10k to 15k BTU. My main concern is to warm the place up rapidly.

I know the OP was not trying to spend a lot of money but this situation is perfect for a cat stove. You can get a large enough one to really crank up the heat when it's needed upon arrival, but can then cruise along low and slow once the place is heated up.

Thanks, I looked into those. The price point is certainly higher than I would like. There is also the catalyst that bothers me. I have been focusing on building the cabin so the wood that I have is still the trees that were cleared by bulldozer 18 months ago. They have been sitting on the side uncut and unsplitted. I am not sure how dry they are. I don’t want to ruin the stove.

Thanks for your help!

 

[kborndale]

The cabin is off the grid so the electric heaters are probably not going to cut it. I can and will definitely get some LP heaters

That’s exactly what I was afraid of. From all the calculation I made, it looks like I can maintain the temperature with 10k to 15k BTU. My main concern is to warm the place up rapidly.

Thanks, I looked into those. The price point is certainly higher than I would like. There is also the catalyst that bothers me. I have been focusing on building the cabin so the wood that I have is still the trees that were cleared by bulldozer 18 months ago. They have been sitting on the side uncut and unsplitted. I am not sure how dry they are. I don’t want to ruin the stove.

Thanks for your help!

Dry wood is just as important in non cat stoves. With any modern stoves you will be extremely disappointed trying to burn wood that isn't ready. Split that wood today and it may be ready for next winter, it's too late for this winter.

 

[Gorben82]

So I have decided to “wait-and-see” how a winter goes and to decide when I have some experience. The cabin is now finished, insulation R20 in the roof (cathedral ceiling), R13 in walls and R10 on the floor. I should have listened other forums for my floor insulation, it gets pretty cold and it is hard to warm up.

When I arrive, the cabin is usually around 25-35F. I bought a ventless blue flame propane heater (30000 BTU). It takes for ever to warm the place. I am at 60F after around 4hrs. It does not help that I need to keep the windows open to vent out the combustion gas. No CO problem, but CO2 rise very quickly and gets very uncomfortable.

I learned multiple things and so far everything that I was told here has been verified (thank you!):
* ventless heaters are a no go.
* it takes around 18hrs with 30000 BTU to be comfortable (ie couch not cold to the touch).
* at identical BTU it seems that convection heater (blue flame) does quite a bit worse than radiant heater (MrBuddy) to keep us comfortable the first evening.
* with an outdoor temp of ~25F we loose around 25F inside overnight (8hrs) when heater is off. Window is cracked open for some ventilation.
* I need to keep the ceiling fan on at all time otherwise the loft overheats and the main area is cold

I also had time to evaluate the cabin layout and stove position. Stove will be in a corner. I have a cross beam right on top of a putative stove that would make installing a chimney a little more difficult. I am not really looking forward to climb up on the roof again to install a chimney as I would try to have no penetration. The cabin is right in the middle of the woods. Lots of tree all around, some with trunks or branches closer than 10ft to the putative chimney. Reasonably, I cannot cut all of them and certainly cannot raise my chimney higher than the trees. Is the 10ft clearance an absolute must?
I looked into propane stove, but I really don’t want to deal with propane. I had a bad experience and it freaks me out.
I also looked into pellet stoves. I don’t mind buying and hauling pellets, I like the fact that I do not have to penetrate the roof, the convenience of being able to start it on a schedule and the ease of controlling the output day and night. I am a little worried about the noise and the electricity usage. I currently have 600w of solar and I could upgrade to 5Kw/h of storage. During the winter that will be insufficient to power a stove an entire week end. I estimate that I will have to run the generator once a day for ~90min to recharge the battery. Do you think it is feasible?

From people with experience, what will be the best option? For wood stove I have been looking at the vermont casting intrepid. It will fit perfectly in that corner hearth that I have, but I am a little afraid that it might not be able to do the job or that I might have to babysit it every couple of hours.

Sorry for the long post, I have been scratching my head on that for a year and I am a little lost. Whatever I do, this is going to be a massive expanse and do not want to regret it.

Thanks!!

 

[EatenByLimestone]

What is putative? It’s mentioned a few times so it’s probably not a typo, but I’m not sure what it means or auto corrected from. Maybe I need to learn a new term?

Pellets are a good solution. Running a generator certainly is a possibility if you run out of battery power. I have some friends who hear their cabin with a pellet stove. I’ve slept on a couch maybe 6 feet from the stove without issue, but white noise doesn’t bother me much. Some people are really bothered by it. It’s not too much more than the blower on my woodstove.

I’m not a fan of Vermont Castings, but many like them. They make a beautiful stove. Some find their operation finicky.

 

[Murray01]

In my opinion go with wood heat. By the sounds of it you are surrounded by free firewood, concentrate on getting it cut and split for next winter. Before we moved full time into our cabin we would come up in early April and open it up for the summer. It would take us 2 full days of wood stove heat to get winter out of the cabin and that’s with mother nature helping heat from the outside. Doesn’t matter what type of heat you use it will take time to heat the building, at least with wood it’s free and readily available

 

[all night moe]

Indeed prep your firewood for next winter. Almost a whole year to save up for a stove.
@begreen I'm thinking a smaller PE stove here or possibly a Lopi. They might fit the bill .....

 

[JamieW]

my cabin is about the same size as yours. I regularly get there and its -20deC outside...and inside the cabin. I had these same dilemmas. Size a stove for maintaining temps...or so it can get up to temp quickly. I initially went for option 1 and installed a True North TN10. It does a good job of maintaining temperature, and I can enjoy a fire without over heating.... but I have unlimited trees for firewood on my property and it really bugs me to burn propane to get the place up to temp. I am in the process of swapping it out for the larger TN20. My thought process on this is

1. according to the epa data they have a similar turn down of 13000btu, the TN20 just has about double the high end btu ability.
2. if it gets too warm, I will open a window (unlimited wood)
3. my cabin is well insulated so i can have a couple good fires per day and maintain comfort. The TN10 was so small it usually burned out if we spent more than a couple hours outside anyway.

Also, after having a few flaming logs roll out of the East/West loading small firebox on the TN10, I am a new believer in the benefits of a North/South loaded stove. This is what actually gave me the final push to go to the TN20.

 

[begreen]

my cabin is about the same size as yours. I regularly get there and its -20deC outside...and inside the cabin. I had these same dilemmas. Size a stove for maintaining temps...or so it can get up to temp quickly. I initially went for option 1 and installed a True North TN10. It does a good job of maintaining temperature, and I can enjoy a fire without over heating.... but I have unlimited trees for firewood on my property and it really bugs me to burn propane to get the place up to temp. I am in the process of swapping it out for the larger TN20. My thought process on this is

1. according to the epa data they have a similar turn down of 13000btu, the TN20 just has about double the high end btu ability.
2. if it gets too warm, I will open a window (unlimited wood)
3. my cabin is well insulated so i can have a couple good fires per day and maintain comfort. The TN10 was so small it usually burned out if we spent more than a couple hours outside anyway.

Also, after having a few flaming logs roll out of the East/West loading small firebox on the TN10, I am a new believer in the benefits of a North/South loaded stove. This is what actually gave me the final push to go to the TN20.

Good decision and choice. There are also the TN25c and the PE Super series that would fit the bill. The TN25c qualifies for the tax credit.

 

[xman23]

For years I would come to the 45 degree house. The temp rise is about 3 degrees an hour. My first simple solution was building a control that put 4 sections of electric heat on a 7 day programable thermostat. The issue is you have to know the day and time your going to arrive. I would have it switch to 65, eight hours before we arrive. Now with internet we leave the house at 45 and connect to a switch that jumps out the thermostat.

 

[Gorben82]

What is putative? It’s mentioned a few times so it’s probably not a typo, but I’m not sure what it means or auto corrected from. Maybe I need to learn a new term?

Pellets are a good solution. Running a generator certainly is a possibility if you run out of battery power. I have some friends who hear their cabin with a pellet stove. I’ve slept on a couch maybe 6 feet from the stove without issue, but white noise doesn’t bother me much. Some people are really bothered by it. It’s not too much more than the blower on my woodstove.

I’m not a fan of Vermont Castings, but many like them. They make a beautiful stove. Some find their operation finicky.

It means "assumed". This is likely where my chimney and stove would be if I decide to go that route.

 

[Gorben82]

Thanks everyone for the feedback. I am in the middle of the woods, but I would not consider the firewood free (only 3 acres). I have probably around 2 cords available to me right now but after that probably not much more so I will have to buy. I will look into the TN20. This is good to know that a E/W stove can have fire log rolling out. Makes sense but I did not think of it. I guess a top loader like the VC may be beneficial then.

 

[Gorben82]

For years I would come to the 45 degree house. The temp rise is about 3 degrees an hour. My first simple solution was building a control that put 4 sections of electric heat on a 7 day programable thermostat. The issue is you have to know the day and time your going to arrive. I would have it switch to 65, eight hours before we arrive. Now with internet we leave the house at 45 and connect to a switch that jumps out the thermo

My cabin is totally offgrid (no cell phone, no wifi and and not connected to electric while I am not there) but that was the main appeal to the pellet stove to be honest. Be able to have it on a schedule to start in the afternoon on the friday. My goal was to have my solar generator inside the cabin for that purpose, but I tested it and without connection to the solar panels the inverter alone would drain the battery in ~4 days so that's a no go.