Our house is about 2100 sq. ft., built in 1910 and has some pretty crummy windows. I just bought and installed our wood cook stove in 2007, and stainless steel chimney, and installed the tile hearth, bought new Stihls (MS250 and MS361), and chains, and chain files, and PPE, and ... So, this year we're saving nothing -- but, we're sure staying a whole lot warmer that we ever did with propane forced air set to 67 during the day and 50 during the night.
We've only burned about 30 gallons of propane this year ... using it to give the upstairs a jumpstart when the overnight log won't cut it with outside temps in the single digits.
I figure we'll have all the stuff we bought this year paid for about a third of the way through next heating season. Then we'll be saving about $2500 a year. If we kept the house as warm with propane as we do with the wood stove, we'd probably be saving around $3200 or better.
God bless,
Chris