Another helpful tip from your Happy Plumber – A common misconception of the tankless hot water heater is that the hot water will be instantly hot. That is not the case. There are two factors. The first is the temperature of the incoming water to the heater. The second is the distance the water has to travel from the heater to the faucet. The tankless heater gives you endless hotwater, not instant. So if you have a large family this would be a good fit for you or if you are like me you could take the longest hot shower : )