Rinnai has an awesome new product. In this video, Matt Risinger is at the Rinnai booth at IBS and excitedly introducing the Rinnai RH 180—what Risinger thinks will set the standard for replacing 40, 50 and 75-gallon hot water heaters. The top features are a standard B vent on the top. If replacing an older 50-gallon gas heater that has a 4-inch B vent, this is the one to look at. It also has a half inch gas line, which every house in America has, so it isn't necessary to go to a larger gas line when you go tankless. At this demonstration is a 40-gallon storage tank and a 91,000 BTU gas burner, totaling double the hot water output of a standard 50-gallon tank heater. If you are thinking about going tankless, this will be a really easy retrofit. No new piping, no new gas lines.