Wood as a Heating Fuel Alternative
Consideration of some Components for Firewood Economics
Author: Martin Twer
This is an online adaptation of MontGuide MT8411.
It provides an estimate how much heating your home with a "traditional, open-faced fireplace" is costing you, and if/how much investing in a new, EPA-certified wood stove could potentially save you over time.
You can also estimate if substituting your existing fuel source with firewood would make financial sense at current market prices.
All default values can be changed!
STEP 1 - Calculate the Unit Cost of your current Fuel
Look at your utility bills to find the total energy charge for a given time period
(e.g. month, quarter, semi-annual, annual) for the fuel used for home heating.
For example, if you heat your home with natural gas, and your utility bill shows two fuels - e.g. electricity and natural gas - use the charge shown for natural gas only.
To determine the per-unit-cost of your fuel, enter the amount (in USD) you were charged, and the amount of fuel used for a given time period.
The cost of fuel (per unit of fuel) is generally expressed as: $/gallon for heating oil, $/therm (or ccf) for natural gas, $/kWh for electricity, $/gallon for propane, $/ton for coal.
Example: Assuming 53 MMBTU (15,533 kWh) as average annual heating demand, estimates for a household could be
|Amount charged||Amount of Fuel used||Fuel Type|
|$1,860||477 gallons||#2 Heating Oil|
|$590||625 therms||Natural Gas|
STEP 2 - Calculate the Costs per 1,000 BTU (British thermal units)
STEP 3 - Determine the Heat Yield from the Wood you are planning to burn.
The heat yield is the amount of heat that you can actually capture from burning wood (air-dried, 20% Moisture Content) in your stove. It is expressed as 1,000 BTU/cord.
STEP 4 - Determine the Break-Even-Value (BEV) for purchasing Firewood
The BEV is defined as the amount of money you can spend for a cord of firewood to
break even on your current utility bills. If you can obtain a cord of firewood for
less, then the difference is how much you will save per cord of wood burned.
If you are spending more for wood than the BEV, you are subsidizing your bill and would be better off economically to heat with other fuels.
However, in order to compare the BEV with the price paid for firewood (if purchased), the cost of the wood stove should be considered as well. In an analysis of this type you should consider the costs on a "per cord burned" basis, which we will do below.
STEP 5 - Determine the Cost of a Wood Burning Unit on a per Cord Basis
STEP 6 - Determine Chain Saw Costs on a per Cord Basis
STEP 7 - Determine Transportation Costs
Transportation costs are those costs associated with hauling a cord of wood from the forest to your home. The amount is calculated on a cost per mile per cord hauled. You will need to know your total cost/mile to operate your truck (including depreciation, maintenance, and fuel) and its capacity.
A cord is a stack of wood that has a volume of 128 cubic feet (4x4x8 feet); depending on the tree species and moisture content of the wood a cord weighs between 2,500 and 3,500 pounds (1.25 - 1.75 tons).
Assume the following:
|Truck type||Capacity in cords|
|1/2 ton (1-foot side racks)||1/2 to 3/4 (.5 to .75)|
|3/4 ton (2-foot side racks)||3/4 to 1 (.75 to 1)|
|1 ton||1 to 1 1/4 (1 to 1.25)|
|2 ton||2 to 2 1/4 (2 to 2.25)|
STEP 8 - Determine the Maximum Round Trip Mileage (MRTM)
The maximum round trip mileage that you can drive to gather your own wood is calculated
by subtracting your total equipment cost per cord (step 6) from the break-even-value
(Step 4) of the wood.
By dividing this difference, called maximum allowable transportation cost (MATC), by your cost per mile per cord (step 7), the quotient is your maximum round trip mileage.
Reducing Transportation Costs
The only significant way to reduce the costs of gathering your own firewood is to
minimize your transportation costs.
Consider doing this:
- Use a large truck to haul your wood. The cost/cord/mile is lower on a large truck provided it is filled to capacity. You might want to scout out potential wood in a small truck before cutting.
- Keep spare parts for your chain saw. You can easily waste $15 to $20 for gas to drive to the woods and back if your starter rope breaks on the first pull.
- Tow a trailer behind a two wheel drive 3/4 ton (or larger) truck. You will be able to almost double your wood hauling capacity at a fraction of the cost.
- Do not overload your vehicle. Haul at capacity, but do not abuse your vehicle. Vehicle breakdowns are a sure way to very expensive firewood.
- Work and drive safely.
- Enjoy getting out into the forest for recreation and exercise. Remember, you are not paying yourself a wage for this work!