I currently have a 50G Water Heater (6 years old) in the far end of my house which does an ok job of keeping up with our needs. Downside is it takes a long time to get hot water to the far end of the house and we do run out occasionally when multiple showers happen.
When I finished my basement I ran copper and electric to put the heater in a more central location. I also installed a valve to separate the hot water going to kitchen and kids bath from master bath and downstairs bath. So now my electric company has a $525 rebate on water heaters and I have several option and have no idea what's the best choice.
1) Replace the current 50G with an 85G
2) Install new 85G in new location, running both in parallel until 50G dies.
3) Install new 85G in new location, and run isolated systems until 50G dies.
4) Install new 50G in new location and plan on running two heaters forever either parallel or isolated.