Stiebel Eltron ACC300 Accelera 300 Electric Water Heater, 80 Gallon, White

This thing is a wonderful example of German engineering! It's big, expensive, difficult to install, and worth it. Think of it as a long term investment. What I like most about it is its simplicity. There is no digital display or useless programming setup. Such features are prone to malfunctions. Leaving town for a week? Just flip the circuit breaker off. The water will probably still be hot when you get back. Due to the heat pump, it sips energy. I was surprised to learn that it draws less than 15 amps! Pair it with a good hot water re-circulation pump and you will have a much better setup than a tank-less heater.Update 2023 : After 8 years of solid service, the unit stopped producing hot water. The cause is either a bad t-valve or pinhole leak in the condenser tubing. Finding a technician to fix it has proven to be impossible. No one in the DFW area will even look at these things, let alone service them. I've made about 50 calls to HVAC companies and water heater repair companies. Once they find out it's a Stiebel-E, they all say ,"Sorry, can't help ya"! And Stiebel Eltron has NO service network in the US. So keep that in mind before you decide to buy one.

I've had this heater for 2 years now and has already paid for itself including installation. I replaced dual 20 year old electric 80gallon heaters with this single unit and so far its been great. I have a large home, with plenty of room in my basement and I think thats key for installation as the heat pump will cool the air around it. The noise is a low quiet drone that is much quieter than my HVAC units it stands next to. I was spending almost $1000/yr to heat water, now I spend around $400***Dec 2018-UPDATE- Unit Heat Pump just went out and I'm on emergency backup mode. I am having an HVAC guy diagnose and will report back. Meanwhile I reduced my rating to 3 stars and it will go lower if it cannot be easily repaired. This expensive unit from this reputable manufacturer should not have any failures only 2 years in service.***May2019-UPDATE- The Unit was diagnosed with a leaking coil. Stiebal sent a new coil and transfer valve, but I had to get my HVAC guy to replace it for me back in January. Unit then worked fine again until now. Water is leaking from UNDER the condensate pan and dripping onto my floor. Now I'm in diagnosis mode again with Stiebel. They tell me I may need a new unit. This is a major pain in the $#! as the unit is heavy and swapping one out will be difficult, expensive, time consuming and a major inconvenience for everyone. Not what I signed up for afetr spending top dollar for a supposed reputable brand. They really should have better engineered this thing for reliability as well as serviceability. I can no longer recommend this heater.**Update Apr2020Here we go again. "New Improved" Condenser that was installed 15months ago is now leaking refrigerant again. Stay away from this product

I've had one for 4 years. After 2 years, a sensor failed. Would not have been so bad, except it was behind the fan side and essentially required arthroscopic surgery to fix it (it was very hard to access). Now 4 years in, I tried to clean the evaporator fins. You need specialized brushes/vacuum attachments to properly clean the fins. Also, some of the coils freeze with about 3 inches of ice. This melts over a spot where there is no condensation pan, so it drips all the way to the floor leaving a puddle every day. For the price, I am not happy with the serviceability or the performance.

I installed one of these in front of our Tempra 24 Plus to use during the summer months, and in case of a power outage. The Tempra 24 is an efficient tankless unit-- however, in comparison the heat pump unit is effectively free to run during the cooling season. I say "free to run" because this unit removes heat from the house that would normally have to be removed by the air conditioning. It also takes some of the strain off of our dehumidifier, as it cools and dehumidifies the air as it runs. In a two-person household, it lowered our electric bill approximately $40 per month. It is worth noting that everything in the house is low water usage-- from the shower heads to the washing machine to the dishwasher.I was a bit apprehensive going back to a tanked unit, as we've had poor results with previous tanked water heaters with regard to temperature regulation. I'm pleased to report this unit keeps the temperature within +/-2 degrees Fahrenheit of the set point. Our previous tanked water heaters would vary +/-5 degrees Fahrenheit or more. The tankless unit has spoiled us with its ability to produce water at exactly the temperature set point, but this heat pump unit is a very close second in its ability to maintain a steady, reliable temperature.I neglected to time how long it took to raise the temperature from cold to the set point (114 degrees F) when it was put into service, but I would estimate that it was approximately 5 hours. It's worth noting that we turned the backup element off, and the unit is running solely on the heat pump. Recovery time may be an issue if you have a big family or are filling a large tub, as the backup element is quite small. However, due to the large capacity of the unit, we have yet to run out of hot water even with multiple long showers, laundry, and the dishwasher running simultaneously.Upon purchasing the unit, I was made aware by the factory that it does make noise, unlike a traditional water heater. I would put the noise level somewhere between a refrigerator and a quiet dehumidifier. Unfortunately, I do not have a decibel meter handy. The unit is in our laundry room in our basement, and we cannot hear it over normal background noise in our house.Some things to be aware of... This is a VERY large and VERY heavy unit. Before the unit is filled with water, it is extremely top-heavy and cumbersome to move around. If you are planning on installing this unit in a basement, be sure to enlist the help of at least two strong people and a heavy-duty appliance dolly, as it weighs about 300 pounds (and, again, is extremely top-heavy). Be sure to purchase and plumb a means to drain the tank; unlike a traditional unit, it is not built with provisions to do so. Due to the very modest power requirements of this unit, you will need to switch out the existing breaker for your water tank to a 2-pole 15A breaker. The unit is also very tall (at 6'4"), and all access to the heat pump, electrical connections, and thermostats is through the top. It is possible to install the unit in a 7' basement, but you should plan ahead to make use of the space between the floor joists to facilitate access to these things. This unit produces condensate while running, so you will need to have some means to drain it-- whether through the use of a pump, floor drain, etc. Since this unit removes heat from the room it's in, Stiebel recommends that it be placed in a room that is no less than 10x10x8.Of all the units I've researched, this is the only one where the refrigerant loop does not interact directly with the water in any way. The high pressure part of the loop (hot side) wraps around the outside of the tank, whereas in other units it is either immersed in the tank or in its own small reservoir with a pump moving water across it. The entire tank is insulated very well with closed-cell foam. In the future I will conduct a test to see if it loses enough heat during the day to start the heat pump running. With our usage, it runs twice a day for less than an hour each time-- only after a major water demand.All things considered, I couldn't be more pleased with this unit and its performance, and I would recommend it to anyone.EDIT: I timed the recovery of the tank from various temperatures and the results are:from 40F incoming water to 125F ~65F ambient air temp 7.5 hoursfrom 50F incoming water to 125F ~75 ambient air temp 5.5 hoursAgain, these times are heat pump only as I disabled the backup element. The hot water was completely exhausted with no residual heat remaining for both of these tests.Edit #3 6 years in and I'm still completely satisfied with this unit. Routine maintenance is a breeze with a long narrow vacuum crevice tool and a microfiber cloth on a stick taking care of removing dust from the fins.