Wood volume to heat home?

[Murphy2000]

I was reading a thread where someone asked how much wood you guys are burning to heat your homes. The replies were interesting. Some saying 2 to 5 cords for a smaller home, others saying 8 to 12 for larger homes, etc etc..

One thing that confused me is if you guys are referring to full cords or face cords?

I have a 1400 square foot home (1978 with extra blown insulation in the attic) and I am installing an Enviro Venice 1700 insert. My fireplace is about 8 feet from the direct center of my home. I'm an hour or so north of the Detroit area and I'm wondering how much wood I'm going to need to keep this place at 68 or so. I have about 5 - 7 face cords of elm, maple and ash saved up.

My brick home is fairly well insulated but I think my windows are the weak spot.

There's a place up the street from me that gets inventory delivered in these heavy wood crates that are made of 1" thick x 5 inch wide rough saw (pine?) boards. They really are 1 to 1.25 inches thick. They have agreed to save them for me but my multimeter came back at 1.5 Megaohms so they are still up around 30% moisture content. Going to have to let them sit for a year I guess.

I'm wondering how much wood I'm going to burn and how much the pine boards will help offset the wood volume I need to collect.

Thanks,

 

[BrowningBAR]

I was reading a thread where someone asked how much wood you guys are burning to heat your homes. The replies were interesting. Some saying 2 to 5 cords for a smaller home, others saying 8 to 12 for larger homes, etc etc..

One thing that confused me is if you guys are referring to full cords or face cords?

I have a 1400 square foot home (1978 with extra blown insulation in the attic) and I am installing an Enviro Venice 1700 insert. My fireplace is about 8 feet from the direct center of my home. I'm an hour or so north of the Detroit area and I'm wondering how much wood I'm going to need to keep this place at 68 or so. I have about 5 - 7 face cords of elm, maple and ash saved up.

My brick home is fairly well insulated but I think my windows are the weak spot.

There's a place up the street from me that gets inventory delivered in these heavy wood crates that are made of 1" thick x 5 inch wide rough saw (pine?) boards. They really are 1 to 1.25 inches thick. They have agreed to save them for me but my multimeter came back at 1.5 Megaohms so they are still up around 30% moisture content. Going to have to let them sit for a year I guess.

I'm wondering how much wood I'm going to burn and how much the pine boards will help offset the wood volume I need to collect.

Thanks,

We are talking full cords. You have about 2 cords available. Might be enough, it might not. You are in a location that gets and stays cold for some time.

I go through 7-8 cords in a poorly insulated farmhouse that is nearly three centuries old.

 

[Shari]

Well, there's a Rule of Thumb floating out 'there' somewhere that says if you heat with oil, each 250 gallons of oil equals one full cord (128 cu.fu., stacked 4x4x8). So, if you have heated with oil previously and used 4 fills of 250 gallons each that equates 4 full cords. A lot of variables in here: type of wood, quality of seasoned wood, seasonal temp changes - so the Rule of Thumb has lots of variables.

Shari

 

[Dune]

I figure for the sake of figuring that a cord of pine is worth half a cord of oak. It is actualy a little better, but there is a big value to me in easy math, and also in underestimating my wood supply (too much is always enough). Further, since a cord of cord wood is generaly under 128 cubic feet, when you account for air space and all, The pine may well replace 3/4 cord of hardwood in btu value.

By the way, I would find some way to double check your moisture meter. It is *possible* the shipping crates are 30% but IMHO unlikely.

 

[RedGuy]

I also live about 1 hour North of Detroit and from the consumtion I'm seing so far I should go through just over a full cord a month. My home is alittle bigger than yours at 1,800sqft, but my stove is not in the most opimal location being at one end of the house set in my fireplace. I've also yet to build a block off plate for the bottom of the flue, so I'm loosing some heat there too. My house is a similar vintage as yours, 1973 with a very well insulated attic (20+ inches blown fiberglass), average insulated walls and old (original) windows. So I would say you'd probably be around a cord a month, maybe alittle less.

 

[joshlaugh]

A lot of factors play a part on how much wood you might burn. Location, size of house, insulation, how often are you burning(24/7 vs evening and weekends), seasoning of wood, species of wood, number of stoves etc.

Every year I track how much wood I burn and what species I burn. I am looking to burn approx 6+ full cords this year. This month will be more than 1 cord with two stoves running 24/7. I also have an 120 year old house and it is 2500sq feet.

 

[Murphy2000]

I figure for the sake of figuring that a cord of pine is worth half a cord of oak. It is actualy a little better, but there is a big value to me in easy math, and also in underestimating my wood supply (too much is always enough). Further, since a cord of cord wood is generaly under 128 cubic feet, when you account for air space and all, The pine may well replace 3/4 cord of hardwood in btu value.

By the way, I would find some way to double check your moisture meter. It is *possible* the shipping crates are 30% but IMHO unlikely.

My meter is a Fluke 177 (very high quality).. I used 2 nails 1.25" apart and hammered about 5/16. My 2.5 year old wood pile came in at ~4 MegaOhms (18% Moisture?) and a standard 2x4 was off the scale above 20 MegaOhms. The shipping crate wood feels very heavy and you can kind of tell its a fresh cut. This is not standard pallet wood.

As for the energy density, here are some numbers to work with...

Full cord of oak = 20 to 25 million Btu's @20% moisture.
Two 55 gallon drums of used motor oil = 17 to 19 million Btu's.
250 gallons of Fuel Oil = 34.5 million Btu's.

I heat my home primarily with this: http://www.murphysmachines.com/boiler.html
I burn about 4 to 5 gallons a day of used motor oil to keep the house at 68-70 degrees when the temps are around 15 to 20 outside. It also keeps my domestic hot water tank hot.
I believe it is much more efficient than a wood stove being that wood has a water content to deal with but I have little real world experience with wood stoves so I'm not super confident in my math in that regard.

I'm really looking forward to the installation of our new Venice 1700. My current fireplace sucks more heat from the house than it puts back and I'm kind of sick of it.

 

[Dune]

I figure for the sake of figuring that a cord of pine is worth half a cord of oak. It is actualy a little better, but there is a big value to me in easy math, and also in underestimating my wood supply (too much is always enough). Further, since a cord of cord wood is generaly under 128 cubic feet, when you account for air space and all, The pine may well replace 3/4 cord of hardwood in btu value.

By the way, I would find some way to double check your moisture meter. It is *possible* the shipping crates are 30% but IMHO unlikely.

My meter is a Fluke 177 (very high quality).. I used 2 nails 1.25" apart and hammered about 5/16. My 2.5 year old wood pile came in at ~4 MegaOhms (18% Moisture?) and a standard 2x4 was off the scale above 20 MegaOhms. The shipping crate wood feels very heavy and you can kind of tell its a fresh cut. This is not standard pallet wood.

As for the energy density, here are some numbers to work with...

Full cord of oak = 20 to 25 million Btu's @20% moisture.
Two 55 gallon drums of used motor oil = 17 to 19 million Btu's.
250 gallons of Fuel Oil = 34.5 million Btu's.

I heat my home primarily with this: http://www.murphysmachines.com/boiler.html
I burn about 4 to 5 gallons a day of used motor oil to keep the house at 68-70 degrees when the temps are around 15 to 20 outside. It also keeps my domestic hot water tank hot.
I believe it is much more efficient than a wood stove being that wood has a water content to deal with but I have little real world experience with wood stoves so I'm not super confident in my math in that regard.

I'm really looking forward to the installation of our new Venice 1700. My current fireplace sucks more heat from the house than it puts back and I'm kind of sick of it.

No doubt a fluke is a good machine, it was more your method of calibration I was curious about. Still curious, since the numbers you presented didn't tell me much, however, I have faith that one so equipped in life as yourself is able to determine freshly sawed wood.

Since you are also handy with charts, there are many charts available which compare btus by wood species.