I am needing to add a water heater (electrical) to an older home (1960's) The house was built and added onto at least twice and we have been remodeling. I finished a bath room last year and placed an electric water heater at that time. Because of the way the house was built it also had a gas water heater. I want to replace that one also and don't know if the panel is big enough. There is a 50 AMP breaker running to an old screw in fuse panel which services the old part of the house including the AC and heating as well as all the lights and switches. The kitchen, addition and new bath and water heater are in the new panel. I think it is a 100 to 125 amp panel. IS there enough power to add the second water heater or do I need a bigger panel?