I had a reputable company come to my home to do a furnace inspection - we are selling our house. The contractor said that we need a new heat exchange (the part is under warranty for 12 more years) but the labor to replace the part is about half the cost of replacing the entire furnace. Seeing as this is a huge expense I got a second opinion. The second contractor assured me there was no crack in the exchanger and that if he took the item in to exchange, they would laugh at him! He proceeded to replace the ignitor, filter and cleaned the parts. He assured me and put in writing that the furance is ok. This contractor is a sole proprietor and is properly licensed also. He claimed the first contractor may have been "scamming" me. Do I get another opinion? I am confused!