annual operation/fuel cost of all types of heaters

This is a hard one.  Prices/availability vary so much from place to place and are constantly changing.

I think the infographic would still be worth it, maybe with a little fine print (propane based on x$ per pound, electric based on y$ per kwh, ...)

Or, better yet, maybe put the math in parentheses below the value, so people can re-figure it out based on their own local rates. (1000KWH X $0.14/KWH)

I can give you a pretty good idea of two of those in WI.  I believe we get somewhat colder temperatures than you do, but I would think they are fairly comparable.  Your numbers for the ones I have experience with are very close to what I have personally paid.

LP cost me almost exactly $1600 in a badly insulated trailer house, and $1200-$1300 in a much bigger but very well insulated house.  This year will be less as I plan to use the two wood stoves more.  I cut my own wood, so monetary cost is minimal and I enjoy cutting wood, so I don't really consider labor a factor.  A person could easily consider it though.

Wood pellets - Just over 3 tons a year is average.  I have used 4 tons in a very cold year.  Last Friday, 3 tons cost me $721.00.  Barring really cold weather, that will last the winter with the few bags I had left from last year.

Good seasoned fire wood here will cost anywhere from $60 to $100 a face cord, not delivered.  I haven't tried to heat our new house solely with wood, so I don't have a total for that.

I heat my mediocrely insulated ranch house with about 3.5 to 4 cords of less-than-ideal firewood each winter.  By less than ideal, I mean fully seasoned but not prime species.  I use a lot of birch, some maple, some poplar and some pine.  If I had oak it would be closer to 3 cords.  

Wood here, I believe, is around $300-350 per cord delivered but probably not fully seasoned.

https://www.pickhvac.com/calculator/heating-annual-cost/

Electric Baseboard

$2431


Heat Pump

$830


Natural Gas

$493


Propane

$1,631


Wood Stove

zero to $1500


modern wood stove

zero to $750


Pellet Stove

$400 to $1000


Masonry Heater

zero to $300


Rocket Mass Heater

zero to $150

https://www.northwesternenergy.com/docs/default-source/default-document-library/billing-and-payment/rates-and-tariffs/montana/fuel_comparisonmt.pdf?sfvrsn=6db3469f_14

starting with wood - say we translate this graph to 5 cords of wood for a montana winter

   $1040

electric baseboard   $4000

air-to-air heat pump $2580

in-ground heat pump $1330

propane $2810

pellets $2710

natural gas $1200

Just checking the wood heat numbers....

Per that chart, 1 cord of wood is 200 therms (or 20 million BTUs).  

Per a fancy forestry site, Doug Fir is 26.5 million BTU/cord (or 265 therms/cord).  So the 200 number is only for the lightest of soft woods.

5 cords of doug fir would be 1350 therms of heat.

If that's the metric, and it's for a 72% efficient wood stove, that means .72x1350 therms is the heat the house needed.  Or 972 therms.  

Electric baseboard would then be 972 therms x 100% efficient x 29.3 kWh/therm = 28,480 kWh.  Multiply that by 0.136$/kWh gives $3,873

So if that's how you want to convert things, I think you're in the ball park.

Note that the "72% efficient" wood stove doesn't give 72% of the heat content to the house. Much of that goes up the chimney in waste heat.

Isn't that the remaining 28%?  I've seen the efficiency of modern wood stoves debated in circles endlessly and if anyone has a perfectly defensible number to propose, then this would be the time to post it.  Then Paul/Mud will be able to do the math easier.

Barring that, 72% seems like a good number.  At that ratio, times 5 cords per year, it gives 972 therms per year.  From there the costs of other forms of heat are relatively easy to calculate.

I paid $255 per cord for unseasoned wood in Vermont in early 2022, so $250 sounds like a very realistic price for wood in US states where wood is plentiful.

"Zero" seems optimistic for fuel cost. Even if the trees are on your property, you are likely to be using a chainsaw and fuel. If they're not on your property, you will be spending money on gasoline or diesel for a pickup or towed trailer. And your own labor time is worth something, since it represents an opportunity cost. You could be doing something else productive with that time. Or you could sell the wood you cut to someone else for cash.

So I suggest the grid assume all heating fuels are purchased at the prevailing rate, and remove the "zero to..." language.

Next, what's the average home size in Montana? I have no idea, but it's going to be a significant factor in driving home heating prices. If someone on this thread can provide that figure with a reliable source, it will help readers outside Montana put it into context.

I believe the 72% or whatever is the ratio of actual BTUs generated to theoretical heat content of the wood. Then some of that goes up the chimney as waste heat, and some as creosote and other unburned compounds. Also remember that a 72% efficient wood stove often does not burn at peak efficiency in real life.

Remember that if a wood stove actually delivered its efficiency rating to the space as heat in real life, there really would be minimal room for RMHs to improve on that. We know that is not the case from direct experience.

This thread is about fleshing out one row of a greater document:

https://permies.com/t/204534/creating-heat-infographic

...  so this whole document is gonna focus on montana.  Largely because it is recognized as a cold state - thus eliminating conversations about florida or "what part of california" or "in texas ..."  

...  the size of the average home in montana is 2000 square feet.  So it makes sense to suggest that these numbers are for a 2000 square foot home in montana, with average insulation in an average place in montana (thus average weather/climate for the state).

All that said, the goal is come up with excellent sources for the data.  I think northwesternenergy is a solid source - that is the power company for a lot of western montana.

"Zero" seems optimistic for fuel cost. Even if the trees are on your property, you are likely to be using a chainsaw and fuel. If they're not on your property, you will be spending money on gasoline or diesel for a pickup or towed trailer.  

Excellent point.  

Maybe for wood burning, we can say that most wood burning operations are rural and there are a few "probablies" that come with that:

   1:  probably have a half cord of wood, free, every year, on average.  Branches that fall of trees in the yard, plus wood scraps from projects in the shop.  So, for everybody, the first half a cord of firewood, every year, is a freebie.

   2:  some folks will buy firewood, but most will get firewood.  

           2a: get firewood.   One cord is very local - within a few hundred yards.  And the rest is from a few miles away.  A few pickup truck loads.  So there is fuel and maintenance for the truck, plus fuel and maintenance for the saw.  Not a free thing.   The northwesternenergy document states $150 per cord.  So if you are getting your own firewood, maybe the expense is closer to $30 per cord.

           2b: buy firewood.  The document says $150 per cord.  Which seems really low. This makes me think that $150 per cord is an average that includes the people that get their own.  


Hmmmm .....    

Okay, here is my idea for a grand summary using the NWE document:   $150 per cord is an average between people who buy their own and people who fetch their own.  So to be very average for the sake of simplifying the document, rather than saying something like "zero to $1500" - maybe the thing to do is to hammer down this average, combined with the first half a cord being free.

Therefore:

wood stove
5 cords
0.5 cords is free
4.5 cords at $150 per cord
$675

modern wood stove
2.5 cords
0.5 cords is free
2.0 cords at $150 per cord
$300

masonry heater
1 cord
0.5 cords is free
0.5 cords at $150 per cord
$75

rocket mass heater
0.5 cords
0.5 cords is free
0 cords at $150 per cord
$0



??

I gotta say, that I think 5 cords of wood, on average, is low.  I would guess six is a bit low for 2000 square feet.  At the same time, I think most people heating with wood probably have a smaller square footage.  So I think 6 cords is about right, but we might be talking about an average home size that is closer to 1500 square feet.  Plus, I think most of the homes heated with wood, will also be the homes that are older and/or could benefit, on average, from better insulation.

I know of larger homes with an outdoor boiler burning 20 cords per year.  And homes a little larger than 2000 square feet burning 12 cords of wood per year.  I also know people heating with 3 cords per year, but when I press them for details I start to hear about other heaters being used a LOT!    So my gut says that 5 cords is too small and it should be about 6 cords.  

I found this from the bozeman daily paper

Typically, a 2,000-square-foot house with modern insulation with wood for its sole source of heating will take four to six cords (per winter)

Anecdotal, but showing what is close.  Also note "with modern insulation".

Combing google ...   a lot of anecdotal stuff ...  "I have a 1200 square foot home and i use five cords!" ...   lots of stuff in warmer climates where they use a lot less wood.  

Can anybody find some harder data on how much wood for montana?

Here is something about montana heat prices:

https://www.montana-dakota.com/wp-content/uploads/PDFs/mt-home-energy-guide-2015.pdf

natural gas $446
electric $1541
air heat pump $963
ground heat pump $440
propane $1145

These are annual numbers.  The document was created from 2015 data.  It seems that this is a company that is paid by a bunch of utility companies in montana and the dakotas.

The data from northwesternenergy.com is from october 2022.  

Average price of electricity in montana in 2014:  $0.0988 per kwurlh

The current price of electricity according to the northwesternenergy document is $0.136.

.0988 * 1.376518219 = .136

Therefore, if I use 1.376518219 on all the numbers from montana-dakota.com I get

electric $2121
air heat pump $1326
ground heat pump $606

And then if I use the numbers from the northwesternenergy document to convert from current electric heat prices to current natural gas, propane and pellet prices to get the same heat ...

natural gas $636
propane $1485
pellets $1437

For the moment, I am going to adjust the wood numbers to start with 6 cords of wood for a conventional wood stove.

wood stove
6 cords
0.5 cords is free
5.5 cords at $150 per cord
$825

modern wood stove
3 cords
0.5 cords is free
2.5 cords at $150 per cord
$375

masonry heater
1.2 cords
0.5 cords is free
0.5 cords at $150 per cord
$180

rocket mass heater
0.6 cords
0.5 cords is free
0 cords at $150 per cord
$15

I think I'd bump up the modern wood stove to 4 cords.  I think my house is pretty average in most departments and I go through around 4 cords of wood a winter.  Not oak, crappier hardwoods and pine.

Mike Haasl wrote:I think I'd bump up the modern wood stove to 4 cords.  I think my house is pretty average in most departments and I go through around 4 cords of wood a winter.  Not oak, crappier hardwoods and pine.

2000 square feet?  Average insulation?  Winter climate comparable to montana?

1260 square feet per floor, two floors.  Good/proper/new insulation in the attic, R3 in the walls (yes, it's silly).  Well sealed.  So that's why I'm calling it average.  If the walls were better it would be above average.  

Winter climate likely the same as the "average Montana".  We're USDA zone 4a here which is the most common color when I look at Montana as a whole

USDA zone map

I have a 500-gallon propane tank, but they only fill it to 80% and I only buy it in summer when it's cheaper. I start the winter full and end up at about 50 - 60% at end of season, so generally use about 25% or 125 gallons. When I filled this past summer, the bill was around $250.

I also have the smallest Vermont Castings stove made and the smallest Stihl chain saw made. My spot under the porch where I stack my wood is about 6' long and I stack a single row about 6' high. I cut my wood to 12" to 14" length. I just looked up and found that a cord is considered 128 cubic feet. I estimate I burn a bit over 1/2 a cord per year sometimes a bit more but never a whole cord, I don't think. We burn a lot more cooking outside than heating the house.

On a cold (25 F or lower) but sunny day, the house is plenty warm from the sun. A hot fire of very well-seasoned black locust burned for a couple hours in the evening keeps it warm till we do to bed. A single 12" log of very well-seasoned black locust dropped in the hot coals will burn, not smolder, all night. The furnace is mostly just used when no one will be home all day.

I harvest from my own renewable wood lots and haul it over to the primary stack with my hand cart. I estimate in a full day of work and one 2.5 gallon can of gas I can cut three or more years of wood. I don't really know for sure because it's been three or four years since I cut wood.  My most wasteful thing is because I don't know how to sharpen a chain, so I just buy a new one every four or five years.

Anyway, estimate high and add it all up per year.
$250 for propane
$2.00 gas
4 hours work
expense of 0.25 saw chains - I have four in stock

About 5 years of well-seasoned black locust is currently under cover, another fifty or more years' worth is standing. If need ever arises I'll ditch the propane.

One of those RMH sounds kind of fun but can't justify the effort and expense of replacing my current system, plus I don't think we really have room for it.

I de-bark my already seasoned firewood as I move the winter supply to the porch. Any live critters I find I feed to my fish all the bug poo and whatever else falls out is saved for my seed starter the next year. Bark itself is used for kindling or sold on Ebay for growing orchids.

Apologies if this is completely irrelevant to Montanna.  Do you guys even have black locust?

Mike Haasl wrote:1260 square feet per floor, two floors.  Good/proper/new insulation in the attic, R3 in the walls (yes, it's silly).  Well sealed.  So that's why I'm calling it average.  If the walls were better it would be above average.  

So if your house was 2000 square feet (smaller) and has average insulation (better) then you might use 3 cords of wood per winter?

Mark,

It sounds like you are doing a hybrid situation.

Even more, black locust has a LOT of BTUs per cord.  A lot more than pine or fir.  

Would you say that our numbers seem about right to you?  Naturally, we would like to find sources for really hard numbers, if you can find them.

I updated the first post.  I suspect that it is not yet perfect, but I think we are getting there.

paul wheaton wrote:Mark,

It sounds like you are doing a hybrid situation.

Even more, black locust has a LOT of BTUs per cord.  A lot more than pine or fir.  

Would you say that our numbers seem about right to you?  Naturally, we would like to find sources for really hard numbers, if you can find them.

I guess you could say it's hybrid, sort of a compound hybrid maybe. The house has a 600 sq ft footprint with two little bedrooms in an A-frame upper story, so 1200 sq ft all together. Downstairs is 3/4 underground on the north and west, mostly windows on south and east.  It doesn't freeze downstairs even with no heat at all. It also stays fairly cool in summer but hot humid air coming in when the door is opened makes it damp without a dehumidifier. I haven't figured out a non-electric method to deal with that, I'm afraid maybe there just isn't one.  

I'll look over your numbers and do a little figuring, but I didn't even know what a cord was, so I don't know if I can be much help or not.

paul wheaton wrote:

Mike Haasl wrote:1260 square feet per floor, two floors.  Good/proper/new insulation in the attic, R3 in the walls (yes, it's silly).  Well sealed.  So that's why I'm calling it average.  If the walls were better it would be above average.  

So if your house was 2000 square feet (smaller) and has average insulation (better) then you might use 3 cords of wood per winter?

My attic is R48 or something (meeting current code) and with the excellent job of leak sealing, I'd say the house is actually equal to an average 1999 built house.  Since my house is two floors, it has less surface area than a 2000 square foot ranch.  So I think it's still comparable to an average house.

Crazy idea...  What if someone posted to the Montana subreddit saying they're doing a bit of research and see if they can get a half a dozen Montanites to say how much wood they go through with a modern wood stove?

Mike Haasl wrote:Crazy idea...  What if someone posted to the Montana subreddit saying they're doing a bit of research and see if they can get a half a dozen Montanites to say how much wood they go through with a modern wood stove?

Because most people that burn wood, use wood heat about 25% of the time.  So they will say they burn on 2 cords of wood and when you start getting into the details, you hear about all the other stuff they do for heat.  Plus, there is a lot to go into about what sort of wood stove they are using.  So you would need to make a questionnaire that covers a LOT of statistical variations.

I'm feeling like my numbers are getting pretty solid ...

According to this site  the price of natural gas in georgia is 2.71 times higher than the price in montana.

https://www.eia.gov/dnav/pet/PET_PRI_WFR_A_EPLLPA_PRS_DPGAL_W.htm
says florida is currently paying $4.633/gallon

i think this wiki is now done.  Mud and I have talked about adding all sorts of other stuff to this, but we feel like we need to stop here and move on to some of the other rows in the upcoming infographic.

You should list approximate man hours per year for each system too as that is another expense.  That is one where wood burning doesn't fair well typically

This house normal operation was passive solar and propane heat using a nearly 100 year old heater so not hugely efficient.  Propane to heat the house ran about 200 to 220 gallons per year.  This is keeping the house extremely comfortable to too warm.  Roll back to 68 at night and heat to 72-74 day time.  On any sunny day by evening it will be pushing low to mid 80's from the passive solar gain.  House was built in 1984 and comes fairly close to meeting modern insulation standards and is tight. 1800 square feet between upstairs and basement.  Haven't bought propane recently so don't know cost.  Roughly 2 hours to service the heater each year.

3 years ago added an active air collector with 33" x 13 feet of area.  Running cooler house down to 50 sometimes with mostly the bottom temp being about 56 degrees.  Running a 30 watt fan about 7 hours on sunny days.  Have enough sun for it to run roughly 4 days a week.  So say the fan is running 4 hours a day for 6 months.  That works out to 21.6 kWh for the year.  At $0.10 that would be $2.16.  Driving it with a computer power supply so a bit more loss there so lets call the electric $4 total per year.  Now I have had 1 year I didn't heat at all, second year I heated for 14 days with propane,  third year I heated for 10 days with propane.  Lets call it 2 weeks each so 17 gallons of propane for each of those 2 years.

Labor about 6 hours per year to wash windows late fall.  Running the collector manually is probably adding 15 minutes per day.   So that 45 hours per year.  Working on the aurdino control system to take that one down to nearly zero though.  Other expense is glass cleaner.  Call it another $10 a year worst case

Expect to be able to get the house to comfortable on solar alone by adding  another 8 feet by 13 feet of collector.  Have the glass gathered free and most of the materials other than the wood purchased.  Having been hoping wood would go down in price.

Can someone explain in a little more detail how the claim of a RMH stove is using 10% as much fuel to produce the same heat as a modern woodstove?

If the modern woodstove is being assumed to be 70ish percent efficient, how are you able to claim that the RMH is being 700% efficient?

Since 700% RMH efficiency isn't possible, are you just claiming that the modern stove 70ish percent efficiency is really just a lot lower, like an order of magnitude lower? That puts a modern woodstove at less than 10% efficiency of combustion and heat transfer to the house it heats. I've never heard of such a claim, but I'd like to understand what the claim is and how that can work.

I understand how RMH work, but I'm having trouble with the claims of them using 10% of the fuel for the same heat output as something measured at well above 50% efficiency.

How does that work?

We will start on the build for our house in 2024, next year. I desperately want a rocket mass heater, I'm trying to be REALLY well preped for old age, I don't want any systems that are essential to be labour intensive when I'm old.
All though, I find it a bit like the argument about mortgages, when people tell me they would rather have a fixed rate "so I know what I'm paying" which equates to paying the maximum for the whole term instead of having big dips where your paying a fraction of the price.
I guess what I'm saying is, one may as well have a system that does require labour such as a solid fuel system where they will have to chop and collect wood, and then either getting a "flick of a switch" system when they are too frail. Or simply using some of those decades of cost savings, to pay someone to do the hard work for you.

We might need to update the infographic since the cost of electricity and natural gas has gone up so much since we first did our research.

Agreed natural gas, electric, propane, and even cord word around my area has gone up if purchasing but not nearly as fast.... propane in bulk about 100 dollars per 100lb tank Average for eltric in KY is 13.31 cents per kilowatt hour. Wood is 250-350 a cord but i can usually get it from fruit tree trimmings for 25 a box so about 100 a cord or so... this is in  my area near Morehead ky .... edit to ad info From 12.21 to 14.58 Dollars per Thousand Cubic Feet last year and this average in KY with looks like that is with almost 90% reporting for both years up to the tenth month this year... hope that makes sense... reading off of some very dry reports LOL

Electricity here is going from 14 cents per kwh to 18 cents.

Natural gas is going from $1.018/therm to $1.303/therm

paul wheaton wrote:We might need to update the infographic since the cost of electricity and natural gas has gone up so much since we first did our research.

The cost of purchased, cut firewood here has also gone up dramatically since this discussion began.

In the most prolific area of the US for biomass production where I live, a ton of corn stalk "hay" sells anywhere from $20-30 delivered within a few miles of the field and farmer.

This has to be one of the cheapest fuels available. Unless you live next to a sawmill and can get free sawdust, consider corn stalk hay bales as a source of cheap heat!