We have had a Yukon Wood-Oil combination furnace for 30 years and have been well pleased. We also have a heat pump that does the heating until the temperature drops below 35, then the wood-oil furnace kicks in. Given the age of our furnace, we'd like to replace it before it croaks mid-winter but Yukon is gone. Any suggestions on a good wood-oil combination furnace? Or is this a dying idea?