A plumber told me that a 50 gallon hybrid water heater would not refill itself as fast as a regular 50-gallon heater, and I would need the next size up when buying a hybrid heater. How true is this? I have a rental house with nine working adults, and our current 50 gallon tank heater is just adequate, no more. I am getting a hybrid, and trying to decide among a 50, 66 or 80 gallon. Thanks so much!