[LarryC]

Erin,

Fastest payback for energy dollar is building envelope improvements. Appropriate insulation, sealing drafts, proper air exchange / ventilation, fixing windows and doors, etc.

Next would be upgrading the heating plant. I will go out on a limb and state that your furnace is probably 2X or 3X larger than it should be. Get a QUALIFIED heating contractor to perform a heatloss calculation for your structure to determine what size heating plant you need. Then determine IF the existing boiler needs to be replaced. Please find a contractor that is familiar with steam systems.

I recomend HeatingHelp.com as a good place to find information about home heating systems, heatloss calculations and finding reputable heating and cooling contractors.

Disclaimer: I am not a heating contractor nor work for any. I do have an interest in old houses and energy efficiency.

Good luck in your new to you house and enjoy it.

LarryC