If your house is heated with oil then it can be costly to keep your house heated with the oil.
Heating with oil can cost you around $4,000.00 to $6,000.00 per year depending on how cold your area gets and what heating oil costs in your area and how big your house is as well as how much insulation your house has.
With wood heat you might spend around $1,000.00 on a wood stove, and then another $1,000 or a bit more to install the chimney etc.
So to get started you might have a cost layout of $3,000.00 at the highest.
The cost of one tank of heating oil should cover the cost of a wood stove and the installation of the wood stove so your payback could likely be one winter if you don't ever fill your heating oil tank back up.
If you get most of or all of your wood for free then there'd only be the cost of gasoline and oil for a chainsaw, the bar and chains, chain oil and then the gasoline in your vehicle to haul the wood.
Over the years you'd likely save $3,000.00 per heating season or more by heating with wood even if you had to buy some firewood.