I'm in PA too. Keep the oil heat add the heat pump. Heat pump will heat your house more efficiently down to around 30, then below 30 the new thermostat with an outside temp probe switches to the oil. Best of both worlds.. Electric back up heat is the most expensive. I have sent several people down this road, My brother in law paid for his new heat pump in 3 mild winters, savings on oil. A heat pump basically is an AC unit with a reversing valve. Don't buy just an AC unit if you already have duct work. My 2 cents.
