My insane way of calculating firewood needs.

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

Kingdoc

New Member
Feb 23, 2015
29
Otsego county NY
So... I have been racking my brain to try and figure out how much wood I would need for a winter. Between online calculators, reading forums, checking websites, estimation, guestamation and consulting tea leaves I got anything from 4 cords to 22.3! I took some things I read and combined them to make what I call the Kingdoc average firewood need scale.
I read that a average log (16" long, 4" around hardwood) lasts between 45 to 90 minutes on a fire, Lets average that to 60 minutes.
I read the average cord of wood holds 600 to 1000 logs, lets average that to 800 in a cord
800 logs divided by 24 (hours in a day) = 33.3 days of worth of logs in a cord! easy peasy!
Lets assume that logs not burned during late night smoldering coals and clean outs are split into kindling to keep the average burn rate at one an hour. That's exactly one cord a month.

Aside from the "moisture content", "efficiency" "steel/iron" "air flow" battles you could have does my system seem plausible? Am I crazy? Should I have gone to bed 2 hours ago?* please tell me what you think below.



* I hope so, flounder, yes.
 
  • Like
Reactions: MomaBear
sleep deprivation commonly causes mania.
 
Put 4 cords of dry wood in the shed and call me in the morning. Pay the lady on the way out.
 
You won't know until you know.

My example: 1850, 1.5 story, 1,700 square foot, poorly insulated farmhouse in far northern NH, open hearth fireplace. We burned 7 cords this year, then bought a ton of BioBricks to help us finish out the season. We're in the middle of getting a Lopi Freedom insert.

I expect with the insert, we'll burn no more than 4.5 cords next year; hopefully, less than 4.

But we won't know until we know.
 
Me - 1850, 2 story, 2800 square foot, poorly insulated civil war era house in central NY. because this was a summer rental for the past 10 years before I bought it and never heated in the winter the previous owners installed electric heat. My electric bill has been around 1100$ for the past 5 months. Please keep in mind until I got the crawl space spray foamed 2 weeks ago I could only keep my first floor at 30 - 40 degrees above outside temperature. The average temperature in my town in January was 8 degrees.
 
Too many variable.

If you are burning 24/7 with any stove (EPA) you will generally run through 3-5 cords a winter IMO.

Those running on the lower spectrum will likely live in a climate that doesn't go below 0 degrees often and have catalyst stoves with less heating space and a well insulated house such that they can choke a fire back and get the longest burn with the lowest heat output but still keep the house warm.

The higher end spectrum will be those backwoods bastards that live in Michigan, Wisconsin ect and the northeast where a good portion of the winter is freeze you tips off cold, burning non-cat type stoves, with houses that are on the larger size or are leaky in terms of draft in either case the stove has to be run hotter and more open resulting in shorter burn times and increased consumption.

24/7 burners can fall anywhere in between the two categories IMO.

After your first year burning though You will quickly know just about how much wood you need each year.
 
  • Like
Reactions: Knots
Buy 5-6 cord. After one year you'll have a rough idea of how much wood you'll need. As mentioned in an earlier post ... whatever you don't use will still be good (actually better in most cases) with an additional year of seasoning.
 
  • Like
Reactions: gyrfalcon
As said above, too many variables. Even when the house is a fixed variable (same house - no changes), you have all the weather variables (a 25 degrees cloudy day is different than a 25 degree sunny day - and then there's the wind), wood species variables, moisture content, split size. Ow! I think I sprained my brain!

You can get a rough number doing what you're doing. Better use of your time would be buying 5-6 cord like Jake said and then just keeping track.
 
Last edited:
I would shoot for 6 cords for a big old house. What stove are you using btw that will help figure things out
 
By any chance are you an engineer? Not a bad thing and I highly respect the profession - just that they are typically "overthinkers"

My Bro in law spent 30 min. standing in front of the ticket counter for the commuter system in Toronto figuring out we could wait in line at every stop and save a nickel. Me, I stepped up and bought the nickel heavy day pass and got a cup of coffee.

Get to about 20 cord and replace what you use every year. Never wonder again.
 
I just keep about 18 cords cut and split and replenish what I use. No calculating, guessing, or running out!
 
23u3dwx.jpg

I started by buying 12 cords - 6 seasoned, 6 semi-seasoned (for the next year), which I stacked in a long row 60'x4'x6' (LxWxH -- the panoramic pic doesn't really give good perspective) . I started pulling from the seasoned end when I started burning. When I finish burning, I call my wood guy and have him replenish my stock. A quick stripe of white spray paint tells me where I left off. The next year I pull from where I left off and continue down the row. Rinse and repeat.

I have a 3500 sq ft farmhouse built in 1738 with hand-hewn 5"x5" oak post and beam construction. The insulation is iffy. I did most of it myself, but the walls aren't your standard 2x4 construction, so there are likely gaps, and the insulation in the roof is no where near adequate since the beams only allowed for R13 insulation. It is still better than what was there before I bought the house (read: nothing).

Last year I went through 6+ cords, burning about 18 hours per day x 5 days plus 24x7 weekends (nobody home from 8a-2p so we'd let the coals burn down and then restart the stove when my ex-gf got home.) This year I've done about 4 cords thus-far, but I have not been home nearly as much as last year. If I actually burned 24x7, I'd likely burn 8 cords or more a year -- I like my house hot, I will easily get the main parlor of my living space into the upper 70's or even low 80's. I use a 10 cubic foot wheelbarrow to transfer wood from the stockpile to house. One load gets me 1-3 days of burning depending on species and how much I'm home. I find white oak gives me the best heat.

Still cheaper than oil.
 
I agree completely with your methods. To me, the best thing someone new to burning could do is, have about ten or twelve cords gathered, cut, split, and stacked immediately. It is a lot of work initially, however, you will from there on have seasoned wood, and know the amount you generally need each year. For me, whatever I use, I replenish, and let it sit for 2 years or so. This way regardless of the severity of the winter, I'm covered!
 
If you have been heating with electricity you can use this calculation, it worked well for me.
1Lb of wood at 20% moisture = 1.9 to 2.19 kWh
So if you divide your total heating electricity use in kWh by 2 you will have the weight of wood you need in lbs.
About 25% will be lost up your flue.
You'll burn 25% more because you can, and warm is good!
So figure 1Lb of wood per kWh you used last year.
1 cord of wood can weigh from 2,000Lbs (poplar) to 5,000Lbs (osage), your choice!
Get stacking.
 
  • Like
Reactions: Oldman47
Get 12 20 cords: 10 cords of ash for the next winter and 10 cords of whatever hardwood for the winter after. Replenish in late winter/early spring for the winter 18 months later. Any unused wood will just be drier the next burning season.

For your home get a large or very large stove; you will need it.

My electric bill has been around 1100$ for the past 5 months.

Just did some rough calculations. If one kWh costs you 10 cents you used 11,000 kWh per month; that's a whopping 37 million BTU! Cord of average hardwood burned in a secondary burn stove gives you about 15 mBTU. Thus, you will need at least 2 cords per month.

Honestly, you will have a hard time heating that home with just one stove. That's wood furnace/boiler territory. Or get the largest stove you can afford (e. g. BlazeKing King, Regency F5100, Hearthstone Equinox, Kuma Sequoia), spend your summer weathersealing and insulating, and be prepared to still supplement with some electric heat.
 
Last edited:
Everyones variables from fuel to equipment make for different anwsers.
Took me 2 yrs to figure i need 5 cords minimum per yr
In time you shall know your magic number too.!!!
 
Me - 1850, 2 story, 2800 square foot, poorly insulated civil war era house in central NY. because this was a summer rental for the past 10 years before I bought it and never heated in the winter the previous owners installed electric heat. My electric bill has been around 1100$ for the past 5 months. Please keep in mind until I got the crawl space spray foamed 2 weeks ago I could only keep my first floor at 30 - 40 degrees above outside temperature. The average temperature in my town in January was 8 degrees.
There are lots of variables so we would just be guessing. What we don't know much about is how often the wood stove will be used, nights and weekends or 24/7? How much of the house will be heated by the stove, one area or most of the house? What improvements will be done before next winter, NY energy audit and followup insulation. What stove, boiler or furnace? And then, will next winter be a repeat of this past brutal winter ? (sure hope not). How warm will the house be, 65 or 75?

$1100 for 5 months is 220/month which really is not that bad for a winter electric bill considering you are heating with electric too. A woodstove with dry wood and some continued improvements on the house should make next winter much more comfortable. I would guesstimate burning about 4-5 cords of wood next season if you put in a centrally located 3 cu ft stove. It won't heat the whole place 100%, all of the time, but it will make things much more comfortable next winter.
 
$1100 for 5 months is 220/month

I got the impression he meant $1100 per month !!!

My electric bill here in New England averages $250/mo w/o electric heat.... I can't imagine what it would cost to use electric heat, converting watts to btu.
 
I got the impression he meant $1100 per month !!! My electric bill here in New England averages $250/mo w/o electric heat.... I can't imagine what it would cost to use electric heat, converting watts to btu.
My electric bill has been around 1100$ for the past 5 months.
It is ambiguous. Kingdoc, please clarify. $1100 a month would be horrific. I could see that for last Jan/Feb, but not last Oct, Nov.. Or were Jan/Feb $2000 months?!

PS: Do you know about NYSERDA?
http://www.nyserda.ny.gov/All-Programs/Programs/Home-Performance-With-ENERGY-STAR
 
Last edited:
Well i know from last yr when i ran outta wood end of jan it cost me $650 for electric heat.
 
I burn pellets but am adding wood next year to off set inflated price of pellets. Year before last I burned 8 tons. I started with just 5 that year and ended up fetching 3 more. This year I bought 7 tons to begin with and it looks like I'm going to have 1.5 tons left. I dont know how this compares to cords but as you can see......mileage may vary season to season. Btw.... I could have burned propane for the price of pellets this year. Thats how much pellets have gone up. I havent bought propane for 7 or 8 years so I had no idea I was as cheap as pellets. I'll be filling the propane tank this year too. That will be a new experience.
 
Even if the OP was an engineer, he is going down the wrong road to figure this out. You don't count or consider burn time per "log". In fact, calculations are fairly meaningless.

Tell us your house size, age, quality, stove, wood species, and if you intend to use another heat source. We can then approximate a safe amount of wood to have on hand based on our combined 100s of years of woodburning experience.
 
Status
Not open for further replies.