Stiebel Eltron 224196 240V, 1 Phase, 50/60 Hz, 12 kW Tempra 12 Plus Whole House Tankless Electric Water Heater, Advanced Flow Control

Our Stiebel has been running for 2 years now with a perfect track record so far. It supplies hot water to 2 bedrooms in the back of the house. We live in OKC, OK and can have some pretty cold temps outside but the Tempra 24 keeps up and can kick out enough hot water even on those really cold mornings when you need a good HOT shower.I got the Tempra "Plus" because it will restrict flow rate to maintain water outlet temp if necessary, something the standard Tempra will not do. Also, its nice to have the digital display on the front of the unit, so you can see whats going on when the unit is in operation. We have the temp set to 128F; the max output temp is 140F. It's totally silent in operation, only thing I notice is that it actually will slightly dim the lights in the house when it kicks on.Installation is simple enough, with the electric feed being the most difficult part to get done at my house. We have the heater mounted in a closet in our hallway, where it just hangs on the wall taking up no room at all. The 24 does require very heavy electric feed to produce such a large temp rise with cold inlet temps, while keeping total flow rate high enough for a hot shower. The electric requirement is 2 x 60 amp single phase 240v circuits. That's a total of 240 amps maximum going to this beast - more than many homes can supply having only 200A service at the main panel (240 amps because each 240v single phase circuit consists of 2 legs of 120v so you'll need room for 4 60A breakers in your panel - plus the main CB must support the 240A max draw)Efficiency: all I can say is WOW. Ditching out liquid propane fired hot water tank was one of the best decisions I've made. Now we only pay for the hot water we use instead of keeping 50 gallons hot 24/7. This has reduced our LP use a bunch - our monthly LP bill dropped substantially. I can't precisely say how much we're saving by ditching the LP system (since we also run LP heat here on very cold days) but its between $20 and $40 bucks a month. Our electric bill hasn't changed either, and we have a precise record of our electric use as reported by our "smart" meter on the house.All in all, I give it 5 stars because of its superb performance, efficiency, ease of installation, and high quality design + construction.

Having lived overseas for many years, I was familiar with tankless hot water heaters, but they were always gas. I was a little weary about an electric unit. After reading many reviews about the different ones out there, I went with the Stiebel Eltron. So far, I have been very impressed.FWIW, I have an 1800 sf older home in eastern PA. It only has 1.5 bathrooms, HE washer, and dishwasher. I have the unit set at 105 degrees. That is more than hot enough for what I need. Perhaps in the winter, I might need to turn it up a little.People has commented on Ytube and other places that water pressure will suffer, but I haven't found that to be the case. In fact, my water pressure actually improved. I'm not sure why. The only thing I could think of is that I installed this unit a little closer to the bathroom, eliminating about 8 foot of copper piping. Also some of the old piping or my old tank could of had some hard water build up.People have also commented about the water temperature fluctuating. I haven't found that to be the case either. I think this only happens with the non "plus" models. The "Plus" model has the advanced flow control that seems to eliminate the problem.Other people have commented about lights flickering. Once again, I haven't found that to be the case. I don't see why this unit would cause that. I would guess those people have some other issue going on in their panel or wiring.I did the install entirely by myself, including the wiring. I'll go on the record that I don't consider myself an experienced handyman, but I have taken a few adult ed courses and read a few books on wiring and plumbing. I also read the Tempra manual front to back, and checked the manufacturer's website for more information.I spent about another $300 at HD for extra tools, parts, and the NM 6-2 wire. I used Sharkbites for all the fittings. The hardest part for me was running the 6-2 wire from the unit to the panel and make it look clean. It took me a full day but I took my time. An experienced person will probably be able to do this a lot quicker.Contrary to what many people seem to think, you DO NOT need to use the Watts tankless heater service valves with an electric unit. In fact, the manual discourages it. The cold side of the unit has a tiny filter screen that needs to be cleaned annually, and the manual says it is best to use flexible stainless steel hoses to connect to the unit.Because I didn't use the Watts service valves, I did install the 3M Aquapure scale filter. This requires shut off valves before and after the filter, one of them with a drain plug, so keep that in mind when planning your install.You also do NOT need to have a T/P valve on the hot water side of the unit. There is a built-in T/P valve. However, if your local inspector won't pass it without one, you might have to install one for show.UPDATE (A Month later): Okay, it has been a month since I've installed this. So far it has been working great. However, I have an LG HE washer. I've noticed if you try to take a shower while the washer is running, there is some pretty dramatic pulsing on the water pressure. Also, because the HE washer rapidly opens and closes the hot water valve, it doesn't leave enough time for the copper piping to heat up to get hot water to the washer. This is not really a problem for me, since I mostly wash with cold water anyway, but for some, this might be a deal breaker. Running the hot water for a minute to heat up the pipes may also be a solution. A small tank with circulation pump might be another solution if you really need your wash water to be hot.A friend who is a fire fighter also recommended that a fire alarm be installed on the ceiling directly above the unit. He has responded to several house fires where the cause were cheap quality Chinese made units. Apparently, the cheap units sometimes catch fire. A fire alarm directly above the unit would have detected when the unit starts to smolder before a full on fire occurs. The Stiebel Eltron is a high quality German made unit, however, fire alarms are inexpensive and make sense as a precaution.