Has anybody here replaced a normal gas hot water service with a continuous one like a Rinnai Infinity? If so, was it difficult and/or expensive? My children are 21 and 19. The 21 yo's partner lives with us and the 19 yo's partner is here probably 4-5 nights per week. Our hot water service is struggling to keep up even with some of them showering the night before. We still often have 3 adults wanting showers in the morning.