I have learned a lot from the craftsmen on this site, and am close to making a decision on a new furnace. One other concern I have is whether to replace my current 13 year old hot water tank with a power vent model, such as a State or AO Smith, to allieviate any potential problems with an atmospheric venting model not venting correctly through a five inch double walled metal exhaust pipe currently being shared with my 80% furnace. I was told by one plumber, however, that the power vent tanks do not have a great recovery capability, and due to the temp of the incoming water in Upstate NY, it makes the recovery slow after a few showers, etc. Is this true? Or will I be OK with venting a new atmospheric tank in the current five exhaust pipe?