Location Fredericksburg VA

I have an older home, with older single pane glass. The original portion of the home was built in 1917 and additions have been added. The home is approx. 3500sq ft. 2 floors, crawlspace and small cellar.

My main heat for 3/4 of the house is oil fired base board heat. I would like to go to a heat pump system for my house. My house is far from being tight. What are some of your recomendations? I have three rooms that do not have baseboard heat. (addition). One contractor recomended putting water coils in the ductwork fed by the existing boiler. The boiler will handle any additional heat requirements.

One contractor is recomending 19seer Trane Affinity and the other is recomending 13Seer Carrier. I would really appreciate some suggestions.