I have a house built in 1966. I had a well guy come out and check the system out and find out why there was so little H2O pressure. Well, the well and pump are in great shape, it is the galvanized plumbing through the house. It was explained that the sediment has collected over time and I need new pipes. Which pipes are better, the copper or the PVC(I know they are some special kind for hot H2O). I am starting to get bids. What questions should I ask? The house is 1430 sq ft.