There are still some X factors that you haven't told us. Are you the guy that has been replacing the windows? If so do you have them all in? How old is your current furnace? Do you have sufficient insulation in your attic? What do you keep the thermostat at? Is is a programable one? Have you had it checked recently? What has the weather been like in your area? Do you have an option for a "budget plan"? The wife and I use this option we pay 138.00 a month every month.
Windows:
I had them replaced by a professional. I would think going from a window with no pane in it, to brand new tinted, dual pane insulated windows would help... but it hasn't, not even in the slightest. They're not all done, but the main portions of the house are done, and all the windows (the two that weren't replaced are caulked around the seals as best as possible) These two are in the kitchen downstairs and the bathroom upstairs.
Furnace:
My furnace doesn't have any paperwork, I don't know how old it is.
Insulation:
Its fine in the attic, as far as the walls I can't tell without ripping the wall down. Portions of the exterior walls that I did put a hole through near the top have fiberglass paper insulation. Couldn't tell you if there is any insulation between the floors. The main problem is the house gets heated, and it all rises to the bedrooms upstairs.
Thermostat:
I installed a new one. During the day in the winter I set it down to 58 so it comes on as little as possible. During the day in the summer I just turn it off so the AC doesn't kick on at all.
Weather:
It's been fucking cold and windy, hence why I'm using a shitton of gas to heat it, even if it doesn't kick on for 9 hours during the day.
I'm not doing a budget plan, I count on the 11 dollar gas bills in the summer. Thats when I have the money to do shit to the house.
What I'm trying to accomplish here is the cheapest to run, highest efficiency way of heating and cooling my house. Just trying to seek opinions on different long term methods (Ie gas, oil, electric, geothermal, etc) of doing so.
Once it gets to be summer again I'll be installing both a new front main door and screen door, along with the frame and insulation around the front door. I also plan on getting a decent size oil filled heater for the main floor. It'll basically heat up oil and blow the heat around. I'd like to run that more than the furnace.