Soapstone and Water Heating Considerations on Buying a Wood Stove

aaronmckeon

New Member
Feb 4, 2020
7
Croydon, NH
Hi Everybody,

I'm trying to decide on a wood stove for my home expansion project. It will need to do the following:
  • Heat a minimum of 1600 square feet (800 downstairs, 800 upstairs, square floorplan) - stove will be centrally located
  • Heat a maximum of 2200 square feet if I add a 600 square foot in-law off the lower level later on down the road
  • Serve as our primary means of cooking in the winter, cook-top and oven
  • Preferably heat our hot water during winter months
I've been researching a lot of options and keep coming back to the Vermont Bun Baker XL (US trade name; Nectre Big Baker Oven elsewhere). So, I have two questions (and a bonus third):
  1. Is it worth it to get the version that's wrapped in soapstone? I love that it'll slowly release heat through the night but am worried that cooking on soapstone could have problems (staining, cracking, etc.).
  2. If I hook up the water heater, it may lose 20% of its heating capacity for the house. At 65,000 BTU's (effectively 52,000 with the water heater attachment), will it still heat the house adequately?
  3. Are there other stoves I should be considering?
For context, we are in Upper Valley NH, which is routinely in the teens and often at or below zero during winter months. Thanks for any and all input!!

- Aaron

 

Woody Stover

Minister of Fire
Dec 25, 2010
11,757
Southern IN
If you put "cookstove" in the title, you'll get some hits. SpaceBus recently got one..
 

SpaceBus

Minister of Fire
Nov 18, 2018
3,592
Downeast Maine
I would not suggest heating a home with a wood cookstove. There are a few units that would work in the winter, but then you can't use them in the milder seasons. This is my first year with the cooker, which became operational the first week of November 2019. If you are serious about being able to heat th whole house and cook with one stove look at the Heco 520 and the Margin Flame view. I don't think anything else could do it, but also expect to use a lot of wood. Modern cookstoves are efficient at cooking food with firewood, but not heating your house with it. We also have a Morso 2B Classic that can heat the whole house, 1200 sqft two story salt box.

The cooker is also plumbed into my home plumbing with a 40 gallon range boiler which then feeds and on demand water heater. My stove has a small water coil, so it's not quite up to heating the water to 120 df all the time since I only burn when I'm cooking. I plan on adding a bit of insulation around my tank until my electric on demand unit turns on less and my tank it still at safe temps. I do have overheat protection on the range boiler along with a mixing valve.
 

jetsam

Minister of Fire
Dec 12, 2015
4,627
Long Island, NY
youtu.be
Soapstone is a serious insulator of heat. Keep it away from your heating appliances if you want them to transfer heat efficiently. I know people want to argue this point, but thermal conductivity is thermal conductivity, and physics doesn't change because the marketing department makes a glossy brochure.

Insulate your stove, the heat goes up the flue instead of into the house.

We don't know much about your envelope's BTU needs, but I would expect that Spacebus is correct when he says that you're better off with a seperate heater and cooker. For one thing, heaters can be designed around large fireboxes, which can lead to more heat and longer burn times, whereas cookers have other priorities to consider. I don't know if there's a cookstove out there that is good at overnight burns, but I'd kinda doubt that even the best one rivals the dedicated woodstoves in that area. (And that is the area that determines whether you get to choose between sleeping through the night or waking up to a cold house.)

Do you have an existing woodstove in the old part of the house that will be helping out?
 

begreen

Mooderator
Staff member
Nov 18, 2005
81,123
South Puget Sound, WA
Agreed, heating a whole house with a wood cook stove is not a very practical plan unless it has a good back up system and is used to supplement. I like the Esse Ironheart for a solid stove and it probably could do most of the heating in fall and spring, but it would need help in the dead of winter.

What will you be cooking with when it's too warm to use the stove? We cook more and more on the Alderlea T6, but no oven baking.
 

aaronmckeon

New Member
Feb 4, 2020
7
Croydon, NH
Thank you, everybody, for your comments. A couple of you have mentioned there aren't good products that can serve both as a cookstove as well as a heater. Is this because they don't throw enough BTU's while still being able to cook? If so, what is the magic BTU number that suddenly qualifies it as being able to heat a roughly 2000 squarefoot home?
 

begreen

Mooderator
Staff member
Nov 18, 2005
81,123
South Puget Sound, WA
Yes. The magic number is a stove with a btu/hr output that meets the house's heat loss at the coldest design temperature. Another desirable design feature is a stove that will burn overnight unless one likes getting up at 4am to reload the stove. What this number is depends on how the house is built, how well insulated and sealed it is, the amount and quality of the glazing , ceiling height. floor construction (exposed slab, crawlspace or heated basement), outside temps and winds.

Is there a primary heating system in the house now? If so, what is its capacity?
 

bholler

Chimney sweep
Staff member
Jan 14, 2014
20,589
central pa
Thank you, everybody, for your comments. A couple of you have mentioned there aren't good products that can serve both as a cookstove as well as a heater. Is this because they don't throw enough BTU's while still being able to cook? If so, what is the magic BTU number that suddenly qualifies it as being able to heat a roughly 2000 squarefoot home?
There are some stoves that will do both. But honestly they still aren't very good heaters when compared to a good modern woodstove
 
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SpaceBus

Minister of Fire
Nov 18, 2018
3,592
Downeast Maine
Thank you, everybody, for your comments. A couple of you have mentioned there aren't good products that can serve both as a cookstove as well as a heater. Is this because they don't throw enough BTU's while still being able to cook? If so, what is the magic BTU number that suddenly qualifies it as being able to heat a roughly 2000 squarefoot home?
Consider that a lot of those BTU are going into the oven, water heating, the flue and cooktop. My cookstove, Tim Sistem North (non hydro), is rated at 31k btu, but so is my wood heating stove. The cooker could heat the house, but I would be loading it every few hours. My Morso, with a smaller firebox, can get more BTU into the house and do it more efficiently with a longer burn time. If you have pots and pans on the cooktop while you are burning then they are also absorbing some of those BTU along with whatever is in the oven.

Don't focus on BTU ratings, they are kind of ephemeral marketing fluff. Instead look at firebox volume. For your house something in the 1.8-2.5 Cuft firebox range for a primary heater would be great. Then pick the cookstove that fits the house best. I personally picked my cookstove for the close clearances, modern styling, water coil, and large oven.

Like I said, the Margin Flameview and Heco 520 could reliably heat your house, but they would be inconvenient in the shoulder seasons and impossible in summer. I also doubt they would burn overnight.

Modern cookstoves are meant to burn hot and fast which doesn't help keep your house warm. On cold mornings I fire up both stoves to warm the house quickly. On sunny days in the winter I don't really have to burn much at all and just cooking keeps the house warm, but cold cloudy days might still require a fire or two in the heat stove. It all depends on the weather.

I would not recommend using a cookstove as a primary heating source.
 

begreen

Mooderator
Staff member
Nov 18, 2005
81,123
South Puget Sound, WA
For heating 2000 sq ft in NH I would be using a 3 cu ft stove unless it's super-insulated.
 

SpaceBus

Minister of Fire
Nov 18, 2018
3,592
Downeast Maine
For heating 2000 sq ft in NH I would be using a 3 cu ft stove unless it's super-insulated.
True, for some reason I was thinking this house were smaller.
 

begreen

Mooderator
Staff member
Nov 18, 2005
81,123
South Puget Sound, WA
I have a friend up north heating a well-insulated 1600 sq fit home with a Summit. Our old 2000 sq ft farmhouse has a 3 cu ft Alderlea heating it in a much milder climate.
 

byQ

Minister of Fire
May 12, 2013
511
Idaho
Oven, cooktop, and heater (but no H2O heating).

 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
20,589
central pa
Oven, cooktop, and heater (but no H2O heating).

And a huge price tag. Do you know if there is some way to bypass the main part of the mass on them to cook without heating much?
 
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SpaceBus

Minister of Fire
Nov 18, 2018
3,592
Downeast Maine
Oven, cooktop, and heater (but no H2O heating).

That's beautiful piece, but I would hate using this in the shoulder season. Something I love about my cooker is the quick heat up and cool down.
 

webby3650

Master of Fire
Sep 2, 2008
10,800
Indiana
Oven, cooktop, and heater (but no H2O heating).

Enormous price tag! What would he be looking at for this heater? Around 30K? With a heating capacity of about 1000 sq ft. I was very surprised at how little square feet they are rated for.
 
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aaronmckeon

New Member
Feb 4, 2020
7
Croydon, NH
For heating 2000 sq ft in NH I would be using a 3 cu ft stove unless it's super-insulated.
Thanks, SpaceBus and Begreen. The stove I was looking at, the Nectre 550 only has a 1.55 cubic foot firebox, the top of which is essentially the cook surface. The oven below the firebox only receives heat when you want to cook because there is a lever you pull that redirects exhaust around the oven, so most of the time all of your heat will be heating the cook surface, steel frame, and the water coil if you've got it. Going off the size of the firebox alone, it sounds like this won't be big enough, but there are reviews of people raving about how much heat it puts out, including one person who has a three story 1500 square foot home that it keeps very warm in winter conditions comparable to mine (stove in corner of the basement) with the top floor actually being too hot. I realize that's 500 less square feet but my house will only be 2 stories with the oven located in the middle of the first floor.

I had looked at the Tulkivi's but they are wicked expensive so wrote them off. I'll look into the other ones you suggested.

Capture.PNG
 

SpaceBus

Minister of Fire
Nov 18, 2018
3,592
Downeast Maine
Thanks, SpaceBus and Begreen. The stove I was looking at, the Nectre 550 only has a 1.55 cubic foot firebox, the top of which is essentially the cook surface. The oven below the firebox only receives heat when you want to cook because there is a lever you pull that redirects exhaust around the oven, so most of the time all of your heat will be heating the cook surface, steel frame, and the water coil if you've got it. Going off the size of the firebox alone, it sounds like this won't be big enough, but there are reviews of people raving about how much heat it puts out, including one person who has a three story 1500 square foot home that it keeps very warm in winter conditions comparable to mine (stove in corner of the basement) with the top floor actually being too hot. I realize that's 500 less square feet but my house will only be 2 stories with the oven located in the middle of the first floor.

I had looked at the Tulkivi's but they are wicked expensive so wrote them off. I'll look into the other ones you suggested.

View attachment 256541
You can do whatever you want. In my experience of owning a cookstove with a 1.3 cuft in Downeast Maine in a well insulated 1,200 sqft house I would go through twice the wood and load two or three times as often to heat the house. My 0.84 Cuft Morso heats the whole house on 3-4 loads a day, about 40 lbs of softwood. It would take 80 lbs with the cookstove. The oven is still absorbing heat from the firebox even if the oven is not engaged. Heat radiates in all directions, only hot air has a tendency to rise due to changes in density.
 

aaronmckeon

New Member
Feb 4, 2020
7
Croydon, NH
Like I said, the Margin Flameview and Heco 520 could reliably heat your house...
Just checked out the Margin Flameview and Heco 520. The biggest thing that turns me off from those is that I don't want one with a back to the cooktop, mostly for asethetics because the stove will be located on an island and I want visibility through it. Do you know of any others that would be open on top but have a bigger firebox? To circle back to the concept of having two stoves, one for heating and one for cooking, I just don't have the space given how the first floor will be laid out. Also worth mentioning, the top floor of the house will only be 784 square feet. I would think through convection that heat would rise and then be trapped in a relatively smaller space. Is this incorrect thinking? Thanks again for all the help - my first time buying a woodstove, hence all the questions!

- Aaron
 

coaly

Fisher Moderator
Staff member
Dec 22, 2007
3,711
NE PA
I heat under 2000 sf with a Kitchen Queen 480 capable of heating up to 3000 sf.
Larger water capacity, thermostat, no cementing gaskets, no complaints.
Check out the new Grand Comfort;
 

SpaceBus

Minister of Fire
Nov 18, 2018
3,592
Downeast Maine
Just checked out the Margin Flameview and Heco 520. The biggest thing that turns me off from those is that I don't want one with a back to the cooktop, mostly for asethetics because the stove will be located on an island and I want visibility through it. Do you know of any others that would be open on top but have a bigger firebox? To circle back to the concept of having two stoves, one for heating and one for cooking, I just don't have the space given how the first floor will be laid out. Also worth mentioning, the top floor of the house will only be 784 square feet. I would think through convection that heat would rise and then be trapped in a relatively smaller space. Is this incorrect thinking? Thanks again for all the help - my first time buying a woodstove, hence all the questions!

- Aaron
My first floor is like 24x32 with one L shaped living/kitchen/dining room, one 8x9 "bedroom" and a utility closet and we have two stoves. The upstairs is smaller since it's a saltbox. It can be done if you shop for the correct stoves. I don't know if the Heco can be had without the backsplash or shelf. Can you post a layout of your floor plan? Most cookstoves don't have an attractive back side. Are you committed to heating your domestic hot water with the cookstove? If not, you have a few more options. Something to consider for full time heating would be a unit like the Tim Sistem North Hydro. This unit is a cookstove and hydronic heater in one system and could possibly heat your whole house and still work for cooking. It might be a creosote factory and require frequent cleaning. I take my ash vac to my cooker every month. I do really like the glass cooktop on my North (non hydro), but this is only available with rear vent.

Link to the hydro model: https://woodstoves.net/abc-products/tim-sistem-north-hydro-wood-fired-boiler-oven.htm

Edit: If you do go with the hydro, get a lot of thermal storage so you don't have to keep it fed constantly. It would be most efficient to burn it hot and fast when you cook and all the excess heat will then be delivered to thermal storage to keep your house warm when you aren't burning. This could be 500-1000 gallons of water then circulated through radiant flooring heat, panel radiators, cast iron radiators, or baseboard emitters. Radiant floor heat and the high efficiency panel radiators work with low water temperatures which means more heat from each piece of wood.
 
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bholler

Chimney sweep
Staff member
Jan 14, 2014
20,589
central pa
Just checked out the Margin Flameview and Heco 520. The biggest thing that turns me off from those is that I don't want one with a back to the cooktop, mostly for asethetics because the stove will be located on an island and I want visibility through it. Do you know of any others that would be open on top but have a bigger firebox? To circle back to the concept of having two stoves, one for heating and one for cooking, I just don't have the space given how the first floor will be laid out. Also worth mentioning, the top floor of the house will only be 784 square feet. I would think through convection that heat would rise and then be trapped in a relatively smaller space. Is this incorrect thinking? Thanks again for all the help - my first time buying a woodstove, hence all the questions!

- Aaron
When you say in an island what exactly do you mean? Most cook stoves still have decent clearance to combustibles. If they don't they are heavily insulated which makes them great cookers but not very good heaters. For myself I would never consider a cookstove for a primary source of heat. There are just to many compromised made. A good modern wood stove for heat and a good cookstove for cooking makes allot more sense.
 
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