Why do I have to wait to get hot water after turning on the tap?
The wait time to get hot water is primarily determined by the distance between the water heater and the point of use. Rinnai tankless hot water heaters produce hot water within just a few seconds of first water flow from a cold start. However, all the cold water must be purged out of the pipe between the hot water heater and your point of use. For example, if your kitchen sink is 50 feet from the hot water heater and the water flow rate is one gallon per minute, it will take 90 seconds or so for hot water to reach your sink.
Because of their small size, you can place a Rinnai tankless water heaters in locations that you could never place a tank. If you have your Rinnai hot water heater close to your primary points of use—such as the kitchen or master bath—you’ll drastically reduce the wait time.