Make sure to check with your local utility as well. You might be able to get tax breaks and/or discounts for switching to a high or ultra-high efficiency furnace. We had to replace our old oil burner in '01. Between tax breaks and discounts we saved $1500 and the energy savings were pretty amazing. We went with an ultra-high efficiency furnace which is so efficient it exhausts through a PVC pipe instead of a metal chimney. The PVC barely gets warm. That means the heat is going into my house, not the atmosphere.
