You can see how compact the unit is compared to the tank, and how straightforward the installation is.
The white dial allows you to set the water temperature digitally, from 86F to 125F. The unit automatically works out how much heat it needs to add depending on the temperature of the incoming cold water.
So we now have a simple, compact, cost effective, 20 year+ method of making an unlimited amount of hot water. These systems are in common use in Europe and Japan, and are finally catching on here in North
America. If you have a source of cheap electricity, I strongly suggest you look into these units. Stiebel seems to be the market leader, but Bosch, Seisco and SETS Systems are also available.
If your electricity cost would be prohibitive, but if you still like all of the benefits shown above, you could use the natural gas or propane tankless units from Rinnai, Paloma, Takagi or Rheem.
Note that these units are either mounted on the outside of an exterior wall, or mounted on an inside wall with a pipe-in-a-pipe to the outside to bring in fresh air and exhaust the combustion gases.
After running the system for over a month now, I have to say I'm quite happy. The hot water is, well, hot! I set the temperature on the low side, then bumped it by 1 degree C several times. We are
now sitting at 44C and everyone in the house is happy.
I did some real-world power draw testing with one shower on full hot, and this is what I found:
Lowest setting: 30C / 86F: 2.1 KW
Our current setting: 44C/111F: 7.9 KW
Highest setting: 52C/126F 10.9 KW
This means if someone has a 10 minute shower at our current setting, the system will consume 1.3 KWh. Calculate at your electricity cost to see what this means to you. At a hypothetical 10c/KWh of grid
power, that's 13 cents. Not too bad given the cost of other things these days.
Although the heater is rated (and must be wired and have circuit breakers for) 24KW, the system is using significantly less than the maximum, even at the highest temperature. This is due to the unit being
adaptive to the incoming water temperature and only heating it enough to reach the user's setting. It's summer now and the normally cold well water is being warmed up through the near-surface piping from the
well 4 houses up the street. Power draw will go up slightly in the winter months.
An added benefit of replacing the old, rusting tank is a feeling of full rinsing in the shower! With the tank, it never felt like the soap was completely rinsing off, but it was more likely rust, sludge or
other stuff in the tank being sent down the pipe with the water.!