What to Expect from a Tankless Water Heater
The Stiebel Eltron Tankless Water Heater does not work in the same way as a conventional water heater. The Stiebel Eltron Tankless Water Heater heats water to the temperature that is required for personal hygiene purposes and not to 120°-140° like a conventional water heater. The only reason a conventional water heater 'superheats' water to 120°-140° is so that the limited volume of water it holds can be extended by mixing it with cold water. Not only does this waste energy by heating the water and then cooling it again, but it increases the possibility that a child or elderly family member will scald themselves accidentally. The process of 'superheating' the water is not necessary with the Stiebel Eltron Tankless Water Heater because it produces an unlimited supply of hot water.
We suggest that when the Stiebel Eltron Tankless Water Heater is installed it is adjusted so that those who like the hottest shower in the home are comfortable with the hot water valve set to maximum and the cold water valve off. This effectively eliminates the waste of energy associated with heating water to a temperature greater than that which is necessary for personal use. It also eliminates the possibility of scalding injuries.
Each time you use hot water the Stiebel Eltron Tankless Water Heater goes through a 2-3 second cycle to regulate the temperature of the water to the setting on the thermostat. When you turn on your shower or a faucet, you will generally only use your hot water valve. Don't expect the water to get as hot as it did before you installed the Stiebel Eltron Tankless Water Heater, because it will already be adjusted by the heater to your set point temperature so you will not have to mix cold water with it.
A tankless water heater is not an 'instant water heater'. It will not reduce the time it takes for the hot water to reach your point of use. The only way to do this is to install the Stiebel Eltron Tankless Water Heater closer to the point of use. However, if this is your goal, the size of the Stiebel Eltron Tankless Water Heater allows it to be installed almost anywhere.