Using the standard base of 65 degrees F., how many average annual "Heating Degree Days" are there where you live?
For my area of Ohio the average annual HDD figure is 6,148
Here is a link to historical average monthly and annual HDD's by city for the entire country. http://ggweather.com/ccd/nrmhdd.htm
I've found that my heat demand (coal usage) tracks my local HDD's quite linearly on a daily/weekly/monthly (and yet to be seen, but assumedly also annual) basis.
For the months of December and January I'm burning a highly repeatable (and now, predictable) 1.63 lbs. of coal per HDD per day.
If I took this principle even farther and I moved my house( with no changes made to it) to an area with 8,000 annual HDD's, then I should expect to burn more coal to the tune of 30% annually, since 8,000/6,148 = 1.30