As an electoral wholesaler / distributor and owner of my very own Stiebel Eltron Tempra 24 Tankless Water Heater which I installed in my own house. I will be happy to tell my own story and information about this heater and feed back  from my current customers. Click here to read my story... When buying a electric tankless water heater there is a lot more research that is needed before you buy one. A tankless water heater is a 3 part equation 1) how cold water coming into your house in the winter time.  2) current water pressure 3) how much power to you have.  I personally believe the electrical power you have is the most important part of the equation. They need a lot more POWER then a standard tank water heater  and because of that you really need to consult a election before you buy one to make sure you have the power needed.  YOU CAN NOT FUDGE IT, this tankless water heater needs the exact amount of amps specified or else  it will not work, period.  If you don't have the power, don't go any further with your research. The Tempra 24 Plus can heat on shower or two sinks at the same time in cold environments. I live in New Hampshire and in the winter the city water is between 50 and 55 degrees you like to keep the water temp around 110  -115 degrees it can get one shower hot water very hot, but we can not do two showers at the same time so when company stays over unfortunately its pick an number  to see who goes first and who goes last.. the good news is if you are last there is still plenty of hot water.