My forced hot air furnace used to have efficiencies in the upper 80's but is over 20 years old and now down to 80%.
If you have replaced a furnace at what point did you do that?
Several people have told me natural gas is more efficient and I have a line to my house, but the utility company is horrible, a monopoly with no accountability, and I do not want to go that route. If anything I would like to get my hot water off gas and onto oil if/when I replace the furnace. The oil tank I already replaced some years back. Oil heat is common in my area with a good competitive market for fuel, repairs, and installations.
It would be nice to add central air also, but I think that could involve other things like upgrading the electric.
My inclination is to stick with the furnace until it dies.