The cost for a water heater is something that we always come out to look out before providing a price. The things that we need to look at are going to be used in determining if there is a need for a thermal expansion tank. A thermal expansion tank is used to protect the plumbing supply lines from excess pressure. In some water heater installations there is more work involved than just swapping out tanks. Some of the common changes when dealing with an older water heater involve adding black iron gas pipe to meet current building codes. Often the water heater will not include a drip leg or copper may have been used. We can thread new pipe while at the jobsite, so getting your house up to code is no sweat.
Bradford White is among the leaders in water heater. A 50 gal tank with a 4″ flue is $600 for the tank. If you have a 3″ pipe the cost is $380 for the same water heater.
If you want something that is a little more efficient Bradford White also offers a residential power vent combo TTW. The Energy Saver Gas Combo Heater System is among the most efficient systems available. The 50 gal tank is $1200 plus parts and installation.