Install tank water heater in the same attic location as the current tank water heater over the kitchen.
Install tank water heater in the same attic location as the current tank water heater.
Connect to existing 1" gas in the attic and run approx. 8' of new 1" gas to the tankless water heater
Install new rinnai rxp160in tankless water heater in the same attic location as the current tank water heater.