If you own the house insulate and then insulate some more.If you rent try to persuade your landlord to insulate. I am a retired natural gas utility employee and I can tell you that most homeowners will spend the money to insulate their homes to keep their costs down and most landlords don't want to put money into their rental properties.This results in the people that can afford it the least having the highest heating bills. A lot a old houses lose heat like a chimney if they are not insulated.The price of heating oil fluctuates and sometimes it is cheaper than natural gas and propane and sometimes more expensive. Electricity (Hydro) is always the most expensive form of heating. That old furnace can also be converted to operate on gas or propane. If things stand as they are you will be filling that tank up alot. A 1 floor house loses most of its heat through the roof and a 2 floor loses more heat through the walls.On a 1 story house you should concentrate on insulating above the ceiling,on a 2 story focus on the doors and windows.I reread your post and I see that you own it. Insulate like crazy! If it is a brand new house you would be better of to bite the bullet and have a professional insulate the place.In the long run you will save.