The Stiebel Eltron Accelera 300 Heat Pump Water Heater enters the heat pump water heater race a little late but with a big bang! Stiebel Eltron unveiled their effort behind GE, Rheem and Ruud with a totally different design that offers an 11 to 15 gallon higher 1st hour delivery above competition with a 2.5 energy factor. Stiebel Eltron is a German based corporation that was founded in 1924 by Dr. Theodore Stiebel in Berlin, Germany. Today they are worldwide with approximately 3,000 employees in plants located in Holzminden, Germany; Eschuwege, Germany; Slovakia, Thailand, and China and other facilities as well. The sales, service, distribution, and parts facility for North America is located in West Hatfield, Massachusetts and is supplied by the Holzminden, Germany plant.
The Stiebel Eltron Accelera 300 Heat Pump Water Heater carries the Energy Star Rating and is eligible for Rebates in the Appliance Stimulus Package of up to $200, Grants in the Weatherization Assistance Program of up to $6500 if you qualify, and a 30% Income Tax Credit up to $1500. These incentives can greatly offset the cost of installing the Stiebel Eltron Accelera 300 Heat Pump Water Heater and allow the energy savings to get into your pocket quicker. Heat pump technology uses a reverse refrigeration process that takes heat from the ambient air and moves it to water inside the water heater. The process does not require making heat and is only moving the heat, which makes the process efficient. The Stiebel Eltron Accelera 300 Heat Pump Water Heater uses 1kWh for its compressor and fan to pump heat into the water in the tank that would have had a heating element use 3-5 kWh to generate.
The Stiebel Eltron Accelera 300 Heat Pump Water Heater is based on an 80 gallon tank designed specific for this application and is not an add on type unit. The heat pump unit is mounted on the top of the tank and that is where the similarities end. The Stiebel Eltron Accelera 300 wraps the tank with the condenser coil to put the heat into the water where the competition is circulating water through the heat pump. This design is simpler and eliminates the use of a pump and its energy draw. When the heat pump cannot keep up with the water use demand there is a 1,700-watt electric element that will automatically turn on to help deliver the hot water that you need. The Stiebel Eltron Accelera 300 requires 220 – 240-Volt electrical power but only requires 15-Amp. circuit breaker with a maximum current draw of 9.16-Amps. This is a drastic reduction in comparison to the competitors that have a maximum current draw of 18.75-Amps. and require a 30-Amp. circuit breaker. The Stiebel Eltron Accelera 300 Heat Pump Water Heater comes with a 10-Year Warranty.
I read the operation manual on this product and it has no way to control it. It is factory set at 140F and cannot be changes. Might be great in Germany but not here. 125F can scald!! Also, an 80 gallon tank that only has a FHR of 78 gallons??? A standard electric 80 gallon has 88 gallon FHR! What good is a high EF if it does not perform at least as good as a standard water heater. I don’t like making lifestyle changes for new technology.
Hi Pops,
The scalding hazard is taken care of quite easily with a tempering valve that mixes cold water with the outgoing hot water.
This also increases the amount of hot water available at 120 Degrees F, and eliminates one of the hazards of lower temperature water. Plumbing codes in many places now dictate 140 Degree F water storage to prevent the growth of Legionella Bacteria in hot water storage tanks. 120 Degrees F is at the upper limit of the prime growth range for Legionella Bacteria while 140 Degrees F kills it. Many countries now require the higher temperature water storage and the use of tempering valves, the US is lagging behind but, there is quite a bit of discussion on it and I predict changes will be coming.
The Stiebel Eltron Accelera 300 is intentionally oversized to an 80 gallon tank for the very reason of the slower recovery which uses 1kw to do the work that your conventional tank does with 3-5kw without losing convenience. If you want to pay for 3-5 times the cost then go ahead and keep your 50 gallon electric heater with its 56 gallon first hour rating.
Thanks for the comment,
Redwood
Howdy, I am just starting to look around for a water heater replacement and have more or less stumbled upon the heat pump option. I am finding that most of the plumbers that I speak with are poo pooing the electric tankless even though the Stiebel Eltron model looked pretty nice, now I see that they also have a heat pump model. Does the Stiebel Eltron model allow for vacation settings like the GE model or for higher power needs when you have company? I am going to continue my google search for folks that may know about installs in North Texas . We seem to be in the dark ages here with high tech stuff.
Hi Scott,
The Heat Pump Water Heater is something that would be a very good option in your area of the country.
When you think about it the heat pump does not make heat but instead takes existing heat from the ambient air and pumps it into the tank of the water heater. This is what gives then the economic edge in operating costs. they can easily put 2 Kw worth of heat into the tank while taking only 1Kw to do it.
The Stiebel Eltron Accelera 300 is a very different design from the GE, Rheem, & Ruud heat pump water heaters which place an equal emphasis on the electric elements and the heat pump with the various modes of operation switching priorities and changing the economics of running. These models have a 50 gallon tank and 2-4500 watt elements in addition to the heat pump which make the water heater require a power supply fed by a 30 amp. circuit breaker.
The Stiebel Eltron Accelera 300 has a larger storage tank (80 Gallon) to make up for the slower recovery of the heat pump with the extra 30 gallons providing a higher 1st hour delivery that will keep you happy with enough hot water. They also have a smaller element 1700 watt providing the back up heating and boost than the others. Putting it in simple term the Accelera 300 is relying heavily on the heat pump without the less economical overrides the other manufacturers are providing. Their upsizing of the tank is what was required to make it feasible.
I believe that the design of the GE, Rheem, & Ruud is part of a marketing plan to make them more palatable in areas where a heat pump would be less efficient in its operation such as the northern tier states. While the Stiebel Eltron Accelera 300 design was not compromised by a design to make it acceptable in areas where the operation of a heat pump is not as feasible like it would be in the southern states where the higher ambient temperatures prevail. On the Accelera 300 there is only 1 mode of operation and that is maximum efficiency.
Tankless water heating is a whole different story and there is good reason why most shy away from electric tankless. While they may have some use the higher costs of electricity kill any chance of economy. Consider some of the whole house units can take up to 160 amps to feed the unit and the flow out of the unit is so low most people quickly see the light. Here is a link to a good read on tankless systems.
On the Energy Star Website they list the savings of different methods of water heating for the average 2.6 person family. I wonder what the college tuition rate is for that .6 person? Any way compared to a standard electric tank water heater, a heat pump water heater will save you $290 per year, and a whole house gas tankless will only save you $115 per year.
I hope this helps clear things up for you,
Redwood
I live in Evergreen, Colorado at 8500 feet. Long winter, but sometimes sunny and mild. This unit would go in my basement which has a wood stove heating it – so temperatures can get pretty warm, but also overnight when I am not attending the fire can get cold. I am thinking this makes this unit (or any heat pump – even the hybrid Rheem, Ruud) impractical. What do you think?
Hi Tim,
Since it would take heat from the room in a sense cooling the room if you have an abundance of heat coming from the stove most of the time and are opening windows to regulate the temperature then it may not be. Also they can function as a electric water heater so having hot water would not be a problem.
My guess is you are probably right and you would not see enough of a savings to justify the higher cost of a heat pump water heater.
Redwood
I have read several reviews on the GE heat pump water heater that complain about the noise of the heat pump. I can find no information on the Stiebel’s sound level when operating. Do you have any information on the sound level? I would be installing the unit in the laundry room which is adjacent to the kitchen. I am thinking that the extra cooling in this normally warm set of rooms would be a welcome adjunct to the air conditioning here in South Carolina. However, we don’t want a lot of extra noise, if it can be helped!
Hi James,
The sound level of the Stiebel Eltron Accelera 300 is measured at 1.1 yards / 1 m : 64.2 dB(A)
I hope that is quiet enough for you. 60 dB is about the range of normal conversation so the noise from the unit 1.1 yards away is like that of conversation.
Redwood
Question – we have a large utility closet that has a dryer, washer and furnace in there. If I am reading this correctly we would save more energy because it is typically warm in this closet? There is room for Accelera. I was getting ready to install a few simple vents but would it be better to just leave the closet unvented (it is not dangerously hot) if this install would benefit from the heat of the air?
thanks
Hi Tim,
Since you refer to this room as a closet, it triggers a how big is the room response.
In the installation instructions Stiebel Eltron states the minimum room volume required for installation of the Accelera 300 is 459 cu. ft. / 13 cu. m. This is to ensure there is enough volume of air in the room to draw the heat out of for the heat pump operation.
Your increasing ventilation to the room does have pro and con sides to it. If you are loosing the heat your furnace and dryer are producing or, gaining heat from a warmer outside when the furnace is in the off season mode would be your 2 sides. You may want to consider venting that can change with the seasons keeping the best of both worlds.
Redwood
I am confused, I am looking to replace a traditional 80 gallon electric hot water heater with the Accelera 300. Is the Accelera 300 a replacement for a 50 gallon or 80 gallon? I have two full and a half bath, two adults and four kids.
Hi Hill,
Water heaters come in many size tanks and different ways and rates of heating.
The sizing is largely dependent on the size of the tank and the rate at which it heats to provide a 1st hour delivery that meets your needs and then recovers at a rate that it is reheated enough to deliver your next demand.
Heat pumps while they are a very economical method of heating water are not all that fast so the Accelera 300 which relies more heavily on its heat pump than the other manufacturers is equipped with a larger tank to provide increase storage to increase the first hour delivery.
What size and type is your present water heater? A model # would be great if you can post it.
Do you have a dishwasher?
Do you have a whirlpool?
Is your present heater adequate for your needs?
Redwood
Red,
It is a AO Smith, Model Type EES 80, Serial# MH96-0036526-913. On the energy guide sticker it says – most 5352 kilh/yr; Based on 1994 study.
I have an old dish washer, Kitchen Aid – Superba, Made by Hobart(looks like it is from the 70′s).
I have a newer, LG Washing Machine-Tromm, model#Wm2277HW Maybe 4yrs old.
The present hot water heater provides adequate hot water on demand. Though I have other issues 1) I have noticed seepage from the tank for the past 4-5 months. 2)My electric bill is $430 a month. My Hot water heater is in the same room(12′ x12′, 8ft high) as my HAVC system – Propane. Am I better off running with a propane hot water heater? Suck up the additional costs of running propane plumbing & venting out the cynder block wall?
Hi Hill,
Your present water heater has a 1st hour delivery of about 81 gallons vs. 78.6 for the Accelera 300.
Your recovery is about 21 gph with a 90 degree rise with your present heater.
I worry some about the heat pumps effectiveness because it is better suited to the southern tier states and I can see you are pretty far north. You will probably see effective heat pump use about 60% of the year and the Accelera only has a 1700 watt back up element vs. the 4500 watts you presently have. It is probably not a good choice in your application.
Propane is a fuel that scares me because it’s price is so closely tied to gasoline. We know what that can do.
I would probably say it is best for you to probably stay the same or, if you do want to go to heat pump consider probably 2 of the Rheem, Ruud, or, GE units in parallel. They will have the 4500-watt back up elements for the off season at least.
Redwood
How do you run two units in Parallel? and of the Rheem, Ruud or GE which do you recomend?
Hi Hill,
This is difficult because the sizing charts for your application say an 80-gallon is what you need. That said, I have lived in a home where the water heater we had was undersized by the chart and we never saw a problem because our usage pattern was spread out allowing the water heater to recover. It is hard to say as your mileage will vary.
The problem is they are not making the size that would match what you have, yet although I have heard they are coming I can’t vouch for the accuracy of it. The problem is if your existing unit is leaking you don’t have time to wait.
In a two water heater parallel installation the piping is an exact mirror image of pipe lengths and fitting use to create an equal flow through the two water heaters. But, with two water heaters you face the additional cost of purchasing the second water heater and eventual replacement. The operational energy usage will be double when heating with double the recovery capacity which would probably allow the economy heat pump only mode to be used much more. However even with double the operational usage when heating water the net usage will be close to the same as a single unit, the reason is the energy used to heat the amount of water is the same regardless of how fast and how many units do it. The standby loss which is fairly small with today’s well insulated water heaters would be double.
Now I have thoroughly muddied the decision making process for you.
I’ll make it easier a little now. As far as recommendations of brands it is really too early to say and there is almost no track record to speak of. This may help, Rheem and Ruud are the same units made by the same company so you are looking at one of them and GE for your choice. I would call GE at 1-888-443-4394 and Rheem at 1-800-432-8373 talking to each of their tech people to discuss your application.
I hope that helps,
Redwood
Red
What are your thoughts on a electric tankless hot water heater? Will it use less electricity than a conventional? What are the pro’s & con’s?
Hill
Hi Hill,
Have a read it this link about tankless then we’ll talk. Tankless Water Heating Guide
The thing that you have to remember is it takes the same energy to raise the temperature of the water no matter how fast you do it. It takes 8.34 Btu’s to raise the temperature of 1 gallon of water 1-degree F. If you fill a kitchen sink with 10 gallons of hot water it will take a little over 2 minutes to do. If you have 50-degrees F incoming water temperatures and heat it to 120-degrees F the tankless water heater will have to put 5,838 Btu’s into the water in that 2 minute time period, while a tank type with storage would still use 5,838 Btu’s but may input them slower into the water.
The savings is from the stand by losses of the water in the tank cooling and having to be reheated which is negligible with the 2″ foam insulated water heaters of today.
I how this helps,
Redwood
Hello,
I live in suburban New York. I am intending to install the acccelera 300 a few feet away from my 168,000 btu furnace, In my basement. The room is 500 sq ft and never cold in winter due to the furnace and slightly humid and a little warmer in the summer….I guess the room would be cooler in summer than now, as the furnace would no longer be used to heat water but almost the same in winter as the furnace would still be used to heat the house.
Do you think that this set-up would mean that the accelera would run on the fan rather than the element and make the anticipated savings.
regards
Hi Richard,
There are a lot of factors that go into properly sizing a water heater and add to that the operation of a heat pump which is an efficient water heating method about 60% of the year in your climate. The point I’m making here is if the heat pump is not making hot water you are relying on a 1700 watt element to produce your hot water. I would suggest reading the comments with Hill for a better understanding.
Redwood
Red
I came across a new 80 gal Hybrid hot water heater from AO Smith it is called Voltex. It has three modes efficencey, hybird & electric. It has a lower 4500watt lower element and a 2000 watt upper element. If I understand it correctly it can be run strictly as a heat pump or strictly as an electric or a hybird(combination of both). What are your thoughts on this unit? I was talking to someone today who told me, I am probably best to buy a tradional electric hot water heater, put a electric timer on to shut off between 12am and 5am (first shower around 7am) and replace the elements every 2 years(build up decreases the efficiency). You have been very helpfull, what do you think?
Hill
Hi Hill.
I have heard of the Voltex as well but have you seen it?
They made an announcement a while ago but as of yet actually seeing it or, finding any concrete details on it remains elusive.
I would Probably in your position consider an 80-gallon conventional unit to be a wise choice but I wouldn’t bother with the timer as it’s unnecessary with today’s water heaters with foam insulation.
Maybe by the next time around the manufacturers will finally have the unit you need available.
Redwood
Red
The information & spec’s are on the AO Smith web site. The unit will be available for sale on 4/23/10.
Hill
Hi Red, We live in Southeast Connecticut. We presently use oil for heat and Electric for hot water. Recently, we have been researching Heat Pump Water Heaters and the Acccelera 300 is among the various models we have come across. Our basement stays at a constant 60-62 degrees year round. The humidty level in the basement is fairly high and we use a
Dehumidfier to keep the area dry. We also have an approximately 80 gallon bathtub and this is the main reason we are looking to change Water Heaters as the electric we have now is only 40 gallons and dosn’t do the job. The Acccelera 300 caught our attention due to it’s 80 gallon capacity of which there are not that many produced. We also liked many of the other options that the Acccelera 300 has. So here comes the question. Based upon the information given to you, would the Acccelera 300 be a good fit in our house. We had looked into oil fired boilers but none met the requirements to be able to take advantage of the Tax Credit. We didn’t even bother looking into tankless heaters which leads us back to the heat pump family of water heaters. The Voltex and the Acccelera 300 both look like they might do the job but I wanted to run it by you first. Thanks Red.
Jay
Hi Jay,
That year round temperature in your basement of 60-62 degrees is heated air for a good portion of the year which is why the economical usage is about 60% of the year in our area. Does your dehumidifier ice up in the colder seasons of the year even though it is in your warm basement? The Accelera 300 only has a 1700-watt element to supplement the heat pump. I would encourage you to look at the data from the NU Hotshot Program to see what kind of results they had in testing.
I really think the Accelera 300 being a heat pump purist type unit is better suited to use in the southern tier states. You will probably be disappointed with the recovery rate for 40% of the year here. Other units that rely heavier on the elements will do better here in my opinion.
Redwood
The warranty is listed here as 6 yr, but on the Stiebel-Eltron website it is 10 yrs. Cost is $2800 though, and State sells an 80 gal heat pump water heater at $2100
Hi Tom,
You are correct the warranty on the Accelera 300 has been upgraded to 10 years. At the time this was published last fall the warranty was 6 years, I have corrected the article thank you for bringing that to my attention. There are quite a few differences between the water heaters offered by the manufacturers. The Accerera 300 places the most reliance on the heat pump to produce the heat for the water The water heaters by the AO Smith companies still maintain the 80 gallon tank for the higher 1 hour delivery but place a higher reliance on the resistance heaters. The GE and Rheem/Ruud in dropping down to 50 gallon place an even higher reliance on the resistance heaters those can be had for around $1600 if you are price shopping.
In Arizona with your climate the Accelera 300 would probably offer you the highest savings.
Redwood
Another Arizonan here…We just installed PV Solar and have some extra capacity so I am looking at replacing our gas water heater. A couple of questions…even though it is made in Germany, this Accelera 300 seems as if it will work best in a hot climate like ours and I am wondering if the design philosophy is different for the Rheem or GE (i.e. were there compromises to ensure broader American usage) and should I factor that in my buying decision.
My other question concerns the location of the heat pump water heater. Right now our gas water heater is in a small room attached to the garage with the gas heater/ac unit. Since the Heat Pump exchanges hot air, would it be better placed in the garage (where we might get some residual cooling benefit?) or keep it in the small room? In either case, is it useful or necessary to vent the cooled air away from the water heater? Thanks for the info.
Andy
Hi Andy,
The Accelera 300 is a definite departure from the designs of the other units.
The other manufacturers opted to make compromises using 4500-watt resistance heating to allow usage in areas of the country where the heat pump operation is efficient only part of the year. Stiebel Eltron kept their unit as a heat pump purist unit.
I would consider it to be a hands down winner for a hot climate like yours.
A garage would probably be an excellent choice for installation in your area. It would help cool off the garage. The heat pumps call for a minimum 1,000 cu ft of air to draw the heat out of. It could be in the smaller room off to the side as long as air circulation was possible so the unit can draw enough heat out of the air reservoir.
Redwood
Hi Redwood,
Great exchange of thoughts and ideas concerning the Stiebel Eltron ACCELERA 300. Here’s another one for you. I’m in Stuart, FL and presently have a late 2004 Rheem Model 82V66-2 (65 gal) in my hot garage doing the heavy lifting. I’m considering the ACCELERA for my next hot water device. There are two of us living here and hot water use would be quite typical for that number, never use the whirlpool and just do washing machine, dishwasher, and personal use. Price tag for the ACCELERA is a bit steep but can be reduced, first by the replacement cost of standard HWH and Florida Power and Light’s rebate (no federal tax rebate left for 2010). Those calculations, I can handle but what about the pay-back period without them? Are there typical or average figures for this by geographical location? That’s out of my league! Got any thoughts or an opinion for me? Thanks in advance.
Hi Gary,
As far as I know there are no figures available like what you are looking for. The DOE has their generic values they apply to all heat pump water heaters but the variables alone pretty much say you won’t find the information unless someone comes up with an on-line calculator where you can plug in your water usage, average incoming cold water temp, average ambient air temp, electric rates, and the figures for the unit, along with probably more than a few factors I’m failing to think of.
I confess I’m not that smart. On my GE GEH50DNSRSA Hybrid Electric Heat Pump Water Heater Review Tim Nelson, Staff Physicist SLAC National Accelerator Laboratory left some comments and he could probably tell you the answer, but it’s over my head.
I can say that you are in an area where the conditions are optimum for using the Stiebel Eltron ACCELERA 300 and you would see the maximum benefits that unit can give you. The Stiebel Eltron ACCELERA 300 will provide a higher degree of savings compared to the units made by the other manufacturers and should work well for you.
I’m curious if you have considered the solar option for your water heating needs.
Redwood
Hi Redwood -
Thanks for your comments and quick response. I was leaning toward the ACCELERA and your comments move me further in that direction. Sure, in south FL you really need to consider solar. I have spoken to friends and neighbors who have solar systems for hot water or pool heating and they’re generally happy with the investment especially with all the incentives that are out there. As I drive around and notice solar collectors, it generates concern on my part. Even in the absence of major storms in recent years, some of these installs look a little shabby as a result of wind, water, and or sun. I guess I’m questioning the design and durability (and maybe installation) of the collectors that I commonly see. I’m not much of a roof guy at this point in my life, so the thought of repair or ongoing maintenance doesn’t excite me too much. I guess I’m looking for a lazy man’s energy efficiency and I think the heat pump would fill the bill. I suppose it’s time for me to get going on this change. It’s just a matter of getting the ACCELERA and finding an installer. Better yet, finding an installer who’s willing to supply the device. See, there’s that lazy guy showing up again! Thanks again and I’ll give you a report once I get myself up and running.
Hi,
I live in Jupiter FL and I have 2 separate 10 year old AO Smith electric water heaters that need to be replaced – one 40 gal and one 50 gal – the 40 serves the downstairs (washer, dishwasher and 1 shower) and the 50 serves the upstairs 1 master bath with separate tub and shower and one full bath. only 4 people live in the house – we rarely run out of hot water but the 50 gal is clearly not enough. the 2 tanks sit side by side in the garage that has ambient air in the 80′s in the summer and 70′s in the winter.
I am considering the AOSmith VOLTEX 80GAL, the Accelera 300 80Gal as my 2 best options and possibly a regular electric 80 gal with an Airgenerate Airtap A7 or A12.
my questions:
1. Is it OK to simply connect the 2 hot water feeds for the house with a T and replace the 2 current units with a single larger capacity unit?
2. which option would you recommend given my situation?
3. do you know of FPL rebate programs for moving to high efficiency heat pump.
Thanks
Hi Stephan,
As you probably realize after reading the information the heat pump water heaters are a little slower in heating but much more efficient. Despite the larger size the 1st hour delivery is comparable to the smaller sized conventional water heaters or, not a whole lot more. So yes ganging two units would probably be best if the water heaters you have now are working correctly and occasionally running out of hot water but you should have your plumber evaluate your needs to be sure. The Stiebel Eltron Accelera 300 has a first hour delivery of 78.6 gallons and the AO Smith Voltex has a 1st hour delivery rate of 70 gallons in efficiency mode and 84 in the hybrid mode where both the heat pump and elements are used.
When you gang 2 units it is not quite as simple as adding a tee or two and plumbing them in together. In theory you want the flow going through the water heaters to be matched where the tanks would run out at the same time. To accomplish this a parallel installation must have matching piping to and from each water heater because water flowing through a pipe has friction losses that occur with pipe size and length, tee’s and elbows all adding up which can affect the flow rates. The total pipes must be equal either on both sides or, with a mirror installation where one water heater has inlet piping that matches the other heaters outlet piping and outlet piping that matches the other heaters inlet piping.
I do not have information on any rebate or, incentive programs that FPL is running but you should check with them to see what if anything they have available.
Redwood
Thanks for the reply Redwood – I think you may have misunderstood question #1 – I am trying to replace the 2 current units I have with a single larger unit – so imagine from the wall I have 4 pipes – 2 cold water that feed into each tank and 2 hot water that feed to different parts of the house – the 2 systems are not connected in any way – so if i replace 2 water heaters with one – I am thinking that I can simply cap the one cold water inlet since I will only need 1 and the connect the 2 hot water systems with a T connector since hot water will flow to wherever it is needed when it is needed. Also any thoughts on the Aigenerate Airtap A7? Thanks again
Hi Stephan,
In that case a Tee is fine for joining the lines but I would be cautious on sizing if you are running out a 50 you may be using more water than can be made in heat pump mode alone.
The Air Generate was okay in its day but these newer all in one units have higher efficiencies.
Redwood