I am in CT as well. I had to replace our furnace this fall. A few words of advice - take them or leave them.
Our furnace replacement, including a more energy efficient variable speed motor, a new water efficient whole house humidifier and an upgraded 4" pleated April-Aire filter ran about 1000.00 less than my wood burning insert and its installation. Go for the furnace.
When you do replace it, shop around, get a few quotes. Don't buy into the 'we do this all the time and we know what size furnace you need' line of baloney. Make them do a Manual J on your home. You will get a quote that shows the exact BTUs you need for heating and whatever cooling needs you may have. I had 6 folks come into my home. I have a 25+ yr old 2500 square foot home with an oil forced hot air heating system. I made friends with the folks over at HVAC-talk.com and read, read, read enough to educate myself enough to be a pain in the butt to the men who came into my house. My previous system was a 113,000 BTU furnace. I had quotes from the 90K btu furnace that was installed all the way up to a 150K btu furnace . Even my oil company who I dealt with for 8 years over sized my furnace quote. If you know anything about furnaces, oversizing is worse than undersizing as it will lead to a huge waste of oil which the oil companies will gladly turn around and sell you.
The furnace I had installed was a ThermoPride oil furnace. It is a rock solid furnace if you are looking for an oil burning one, best option in the oil burning world. We were able to get by with a medium output nozzle once it was installed and tested which gives 72,000 BTUS of heat. That means that the largest furnace estimate I received at 150K btus was grossly, grossly oversized for my home. The folks that did my install hesitated not a single bit when I asked them for the manual-j and they were the only company that didn't give me grief over asking for it. Some men truly take offense over a woman questioning their sage advice! The manual J also proved that the company I went with for my install were the only ones who sized the furnace in their estimate correctly.
The manual J measures doors, walls, windows, takes into account insulation, attics, location, where your ducts are and how many you have. INSIST on a manual J - biggest word of advice I can give.
My house is warmer, more even, and I am running MUCH less oil than I have in the 8 years I have lived here, yes we have had mild weather, but I have had one oil delivery of 162 gallons where my neighbors have had 3 or 4 fill ups so far, even with the mild weather.
One other word of advice, don't skimp on the furnace. The previous homeowners installed a cheapo furnace, it had a hot spot on the heat exchanger within the first few years. We've known since the first cleaning that we were going to have to replace it. It lasted us for 8 years, but we probably over burned a ton of oil in that time. If I knew then what I know now about furnaces, I would have replaced it sooner and saved not only on electricity, but on oil as well.