I think he said electric furnace in the OP. 20MBTU -a cord of mixed birch - is somewhere between 6 and a half million kwh.
5800. I think ( my google-fu is not with me tonight) a 20Mbtu cord of ready to go wood would replace about 5800 kwh.
Given I am paying 27 cents for a kwh up here, almost double the national average; if my primary was electric, a cord of wood at 20Mbtu would be "worth" $1566 off my electric bill.
OP is probably paying more like 10-15 cents for a kwh, so more likely a cord of seasoned wood replace $580 to $870 off his/her electric bill.
At three cords a year he could possibly save enough to pay off a BK 30 and a pro installed chimney in three years, give or take. Plus the toy budget, as
@Ashful adroitly mentioned.
@SD Golden , just about all of us here to actually save money buy green wood and season it ourselves. To really really save big bucks, you got to buy tools and invest time. I can buy standing timber in the state forest for $10/ cord, but I have to go cut it and haul it home. I can get green logs delivered to my driveway around $150-175/ cord. I can get green splits delivered to my driveways for about $225/ cord. I can buy "seasoned" wood all day, but i can't seem to get it delivered at any price.
And that seems to be the rule on this planet. We have a few folks from Australia and New Zealand who keep the website active in May, June and July, and a few more from Europe, I don't know of anyone who can buy seasoned ready to burn cord wood, and buy it dependably year after year, and get it any cheaper than whatever other fuel they could be using to heat their home. If you got all three of those, you should buy lottery tickets. The rest of us are buying green wood, or collecting it by whatever means, and seasoning down to dry ourselves.
I have a different skin on my BK30 box, an Ashford 30 instead of a Sirocco 30, but mine really shines with fuel at 12-16% MC. 11%MC and under is kind of exciting. 17-20% is OK-fine, a lot of users here running that - many climates in the lower 48 just won't let folks get wood much drier than 17% no matter how many years they wait. We do have a BK executive who stops buy here often, he has said repeatedly that 22% MC is fine, and he will be the one calling you back if you are running 22% MC and aren't happy. When I can get my fuel under 17%MC, I have a different stove. If I had a corvette, I wouldn't put 85 octane in it.