Can new wood stove connect into old chimney?
This is interesting. You definitely need two flues, one for the wood stove, one for the gas furnace. I have the same situation, however my chimney had two flues in it. Curiously, the flue for my oil burning furnace is not lined with stainless steel, and apparently does not need to be, whereas the flue handling the wood stove does need to be lined with stainless steel. This may have something to do with the corrosive nature of the gases from the wood stove.