Would it be better to move my furnace from attic to basement or...?

add two ventless gas fire place inserts to my existing two woodburning fireplaces(one is on the first floor the other is in basement). I am looking for cost effectiveness and overall resale. The main reason I am interested is my furnace is melting snow on the roof over it. All the ducts are sealed but they must not be insulated enough for the region. Please help