Wood burning stoves are still a popular home heating appliance that was introduced in the 1980s. They are an inexpensive home heating solution. I have used wood to heat my home for nearly 40 years. Additionally, I researched the cost of natural gas vs. the cost to heat a home with wood.
Is a wood burning stove more efficient than natural gas? Using the cost of fuel only, wood heat is less expensive than natural gas heat. There are at least a dozen items besides fuel cost to be factored into the cost of a season of heat. Here is my analysis of these issues and factors including efficient, BTU’s, and actual cost.
Efficiency
The efficiency of a stove and natural gas furnace is not the same as cost. It does affect the fuel cost but is not the same. The definition of efficiency is The ratio of the useful work performed by a machine or in a process to the total energy expended on heat taken in.
Simplified for a wood stove or gas furnace, how much heat we get out compared to how much fuel we use or burn. This is expressed in BTU’s or British Thermal Units.
A natural gas furnace can be between 80% and 98% efficient in its use of fuel. A 90%, and above, furnace burns so efficiently that the exhaust is mostly warm moisture. This exhaust will be sent out of the home through a plastic (PVC) pipe. A true chimney is not even required.
The most efficient wood burning stove is only 70% efficient, so the exhaust is still in the form of smoke and is very hot. A true chimney system must be installed to send the smoke out of the home safely. It must also be capable of temperatures exceeding 1800 degrees F. as a chimney fire is a real possibility if creosote is deposited inside the chimney walls.
BTU’s Natural Gas Vs. Wood
The comparison of natural gas BTU’s vs. wood is not apples to apples, but it is worth looking at. This also gets a little technical. If you don’t like technical details, skip down to “Cost!”
Natural gas is simple. Let’s use a 2200 sq. ft. home. Natural gas is measured and sold in 1000 cubic/feet units. 1000 cu./ft. of natural gas will produce 1015 BTU’s of energy.
Wood heat is not so simple. Different types of wood produce different BTU’s of energy. Generally, the harder the wood, the denser it is, the more BTU’s it will produce. This table has a good selection of firewood BTU values.
| Species | Green Weight Per cord | Dry Weight Per Cord | Millions BTU’s Per Cord | Ease of Splitting |
| Apple | 4850 | 3890 | 27.0 | Medium |
| Ash, Green | 4180 | 2880 | 20.0 | Easy |
| Ash, White | 3950 | 3470 | 24.2 | Easy |
| Beech | 3760 | 27.5 | Easy | |
| Cherry | 3690 | 2930 | 20.4 | Easy |
| Dogwood | 4230 | 27.0 | Difficult | |
| Hackberry | 3980 | 3048 | 21.2 | Easy |
| Black Locust | 4620 | 4020 | 27.9 | Difficult |
| Maple | 4680 | 3680 | 25.5 | Easy |
| Sugar Maple | 3900 | 2750 | 19.0 | Medium |
| Mullberry | 4710 | 3712 | 25.8 | Easy |
| Red Oak | 4890 | 3528 | 24.6 | Medium |
| White Oak | 5570 | 4200 | 29.1 | Medium |
| Osage Orange | 5120 | 4728 | 32.9 | Easy |
| Black Walnut | 4584 | 3190 | 22.2 | Easy |
| Hickory | 5400 | 4650 | 29.2 | Medium |
Choosing White Oak, we have 29,100,000 BTU’s per cord of wood. If we burn three cords in a season, we will have used 87.3 million BTU’s to heat the home. Since the stove is (assuming a good stove) only 70% efficient, it will produce 66.1 million BTU’s over the season. The remainder of the BTU’s or heat is lost up the chimney.
Assuming a 92% efficiency, the gas furnace will in a season use 136,875,000 cu./ft. of natural gas. At 92% this will produce 125.9 million BTU’s of heat.
Using this comparison we have this conclusion.
Efficiency Conclusion
From purely an efficiency of the appliance used, a natural gas furnace is more efficient with the fuel to heat ratio. The natural gas furnace at 90%+ efficiency uses less fuel to raise the heat in the home to the same temperature as a 70% efficient wood stove.
Next, let’s look strictly at the cost in dollars and cents.
Cost of Natural Gas
The actual cost of each product varies from state to state and from company to company if you have natural gas connected to your home, you can purchase gas from any supplier. The transport fee will still go to the company that installed the pipe to your home, but the base price will be determined by the supply company you choose.
I used $9.00/1000 cu./ft. as an average. You can look up the average price of gas in your areas here. http://www.ppinys.org/reports/jtf2004/naturalgas.htm
Cost of Wood
The cost of wood is MUCH more flexible. Ranging from free, if you have a woods and time to cut it, to about $300.00 a cord for cut, split, and delivered wood.
Here is the range starting with the most expensive option. Wood that has been cut, split and delivered to your home is going to run around $300.00/cord. This would include good or premium hardwood and would typically be purchased from the tree trimmers/removers.
The delivery of the wood could be saved if you have a truck and/or trailer to haul the wood. This would also require you to load and unload the wood.
This takes time and effort on you part and should be factored into the equation. You will save about $50.00 a cord to take on this task so around $150.00 for a year’s heat.
Now, you have to adjust for the cost of gas and time if you are moving the wood yourself. If you cut wood, the cost of a chainsaw ($350 – $400), gas and oil for the saw, new chains for the saw, and regular sharpening of the chains.
Next, how are you splitting the wood? Are you going to do it fully manual with a wood maul ($65) or buy a log splitter ($680)? Don’t forget gas and hydraulic fluid for the splitter which will make splitting much easier, but is more out of pocket for sure.
There is also the option of renting a log splitter. Many equipment rental stores have log splitters in their inventory. Be sure to check the size and reserve it ahead as they are in demand in the late summer and fall.
All this is not to scare you away. If you do the math, the long term savings of a wood burning stove are significant. Just be aware of this additional cost. They can add up quickly the first year or so of stove ownership.
Cost Conclusion
As stated at the beginning of the article, purely on the cost of fuel, the cost of wood is less than the cost of a season of natural gas. Just make sure you add in all the additional costs to have a clear picture of the costs for a season of heat.
Work Involved
A discussion of wood burning efficiency is not complete if we don’t discuss the work that a wood burner requires.
Cutting
Cutting and burning your own wood involves quite a list of tasks that some of you may not be willing to take on. I have tried to be as complete and exhaustive (pun intended) as I can be.
Finding wood is a task in and of itself. Unless you have your own woods, if you plan on cutting, splitting, and hauling your own wood, this is a never-ending item on your to-do list. Three cords of wood is a supply of wood that would fill my full-size pickup bed, heaping, 7 times every year. Be prepared to make phone calls and use your contacts to find a continuing source of wood for heat.
Splitting one cord of wood is approximately a three-hour job with a wood splitter. It only takes about one hour more per cord with a wood maul, but your muscles will pay for that kind of speed. It is better to spread that kind of work over several sessions to alleviate the pain.
Stacking
The wood then requires stacking to cure or dry properly. Ideally, the wood can be stacked near where it will be used, so an additional move is not necessary. Wood should be stacked in single rows off the ground to dry or season properly.
Firing the Stove
Actually, putting the wood in the stove is the easiest part of the entire process. The detail most people do not understand is that a wood stove must be stoked every eight hours most of the winter and every six hours when the temperature is below 20 degrees F. It’s not a full-time job but does require consistency. Letting the fire get too low will cool the home and takes additional wood and heat to recover.
That is inefficient. There is a new wood stove temperature monitor that will send you an alarm when the stove is too high or too low. This makes your stove much more efficient and safe from chimney fires. See Tempsure.net for a digital temperature monitor.
Chimney Cleaning
Inspecting and cleaning the chimney is another task that is required with a wood stove. A wood burning stove will build up creosote and other particles in the chimney. This is caused by starving the fire of air and/or burning wood that has not been dried or seasoned properly.
The buildup of creosote in the chimney can ignite and cause a chimney fire. This is the most common cause of fires related to wood burning systems. Cleaning the chimney and removing this buildup should be completed several times each burning season. This assures a safe wood burning system is in your home.
Cleaning the Ashes
The buildup of ashes is unavoidable when burning wood. The ash that is left over from the process must be removed. Depending on the type of wood you burn, you may have more or less ash remaining. When burning wood with an abundance of bark, I have to empty the ashes once a week.
Currently, I am burning the leftover oak pieces from a pallet factory; I only clean my stove out once a month. Check out my post, Do I Need to Extinguish my Wood Burning Stove to Clean It? There are tips and tools for cleaning a stove out, even with it still hot!
Size of the Home
Heating a home with wood heat also depends on the size of the home. My calculations in the earlier examples were based on a 2200 sq. ft. (average size) home. That size home is quickly moving from the average size home to a small size home.
A large home requires more BTU’s to properly heat it (raise the temperature of the air) to keep a comfortable environment in winter. There are larger wood stoves for larger homes. They will also require more wood to achieve the additional BTU’s of heat.
The room the stove will be in will typically be much warmer than the other rooms in the home as the stove radiates additional heat. You will also be bringing more wood into the room and storing more wood outside of the room. These are all factors when considering a stove in a larger home.
Outdoor Wood Boiler Systems
Outdoor wood burning systems or hydronic heaters as they are called can heat large homes efficient if the home has a hot water distribution system. This would mean the hot water is heated in the wood burner “boiler system” and pumped directly throughout the house to radiated water pipes.
This is not a quick heat system that is typical of a forced air furnace system. With a forced air furnace, the temperature of the home can be raised 15 to 20 degrees F in 20 – 30 minutes. With hot water radiated heat system the warm pipes (or radiators) will take much longer to raise the temperature but will keep the temperature consistent, longer once it is raised to the desired temperature.
The downside of an outdoor wood stove is the large amount of wood that is used. Outdoor wood stoves typically burn two or more times as much wood as an indoor wood stove. The lack of heat directly radiated from the stove and the transfer of wood heat to the water results in a much larger use of wood.
If you do have access to large supplies of wood, then an outdoor wood stove is an inexpensive, efficient heat source. Just remember that you will be going outside three to four times every day in the cold to add fuel the fire.
Pellet Stoves
The last type of stove I will mention when comparing natural gas to wood heat is a pellet burning stove. This is really an article all to itself but gets a brief mention here. Pellets stoves are relatively new but are an increasingly popular wood burning option. They are extremely efficient for a wood stove, ranging between 65% and up to 80% efficient. This also results in less ash left over after burning and almost no residue in the chimney.
Most pellet burning stoves meet the 2020 EPA regulation for PM (Particulate Matter) emissions from the smoke. Pellet stoves are also easy to load, once a day in a hopper with less mess than wood.
The only downside is the cost of the pellets. The cost is consistent, and supplies are available at big box construction stores but are higher than firewood.
At 100 lbs. a day a six month burning season would consume nine tons of pellets to heat a 2200 sq. ft. home. A ton of pellets sells for $224.50. That is going to cost $2,028.50 for the season, more than gas or firewood.
Conclusion
Turning up the thermostat on a 92% efficient natural gas furnace is by far the easiest but not the cheapest heat, burning wood is cheaper but a lot more work. It all depends on your perspective, and your age. Your perspective definitely changes with age.
Additional Questions
How much wood will a wood burning stove burn in a season? A typical indoor wood stove will burn three cords to heat a 2200 sq. ft. home. See my article on How Much Wood Will a Wood Burning Stove Burn in a Season for more details.
Does a wood burning stove increase insurance premiums? Yes, but only between 0% – 5% depending on the company! There are many factors that may affect the premium when it comes to wood burning stoves. What questions will by insurance company ask regarding my wood burning stove. Take a look at, Does a Wood Burning Stove Affect My Insurance Premiums for more information on the subject!