I can't really call mine "savings", because there's no way I'd heat with oil again. But comparing past usage in our house give me the following rough estimates:
House is 1400 sq. ft., 2-story Cape, built in 1835 with no insulation, new replacement windows, and the stove/furnaces in the basement.
Oil-fired hot air(first few years we had the house): 1970's furnace, poor condition, maybe 70% efficient, and that's with me constantly adjusting it. Used about 900 gallons of oil. Much cheaper then, but current pricing would leave me using $2,025.00 at $2.25/gallon (no idea what exact price is now)
Coal Stoker (Alaska Konsole II): Used approx. 5 tons of rice coal (anthracite) at approx. $90.00/ton. I bought and picked up my own coal in the summer, would be much more outside the "anthracite belt", and even more for delivery. Did not do a great job due to the stove being in the uninsulated stone basement. So about $450.00 or so for coal, but not great heat. Savings of $1575 (bought stove used for $300)
Wood furnace (paid for with money from 2006 flood ruining my oil furnace and coal stove): Burn lots of wood, maybe 10 cords, less this year due to insulation added in basement, and fact that it's not trying to heat all the masonry down there, just the air in the plenum. Cost: Gas, Chains, and 1 bar ($15 from Baileys with a chain) Total direct cost to me: far less than $100.
So after all that, I guess I could say I'm "saving" $1925.00 by burning wood vs. oil. But to me, the point is moot because I would never return to oil. I just couldn't, in good conscience, pay over 2 grand for something that they suck out of the ground halfway around the world, and ship it here, with the profits going to some of the nastiest, most hateful people on our planet, when I can walk 20 feet out my back door and find a renewable fuel source that doesn't really cost anything. Even if I had to pay for wood, or switch to pellets, I would rather do that then give Big Oil my hard-earned pennies.