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Recommendations for Quietest Heat-Pump Hot Water Heater

user-6798160 | Posted in Green Products and Materials on

I’m waffling between a straight electric tanked hot water heater and a heat pump hot water heater. If I didn’t sleep in the basement right next to the hot water heater, it would be a no brainer, but unfortunately the hot water heater is right next to the bedroom. (A tankless would be nice, but wouldn’t leave any emergency water available, which is a serious consideration for us).

Does anyone have any recommendations on how to find an extremely quiet hot water heater? I considered getting a regular one, and just running it on a timer for when we’re not asleep, but one person takes a shower at night and the other person takes their shower first thing in the morning.

Thanks in advance to the community here.

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Replies

  1. GBA Editor
    Martin Holladay | | #1

    Kathryn,
    When it comes to heat-pump water heaters, I'm not sure which model is quietest, but I suspect that the Stiebel Eltron units are quietest. (Stiebel Eltron heat-pump water heaters are made in Germany, and are generally very well engineered. A Stiebel Eltron heat-pump water heater costs about twice as much as an American-made or Chinese-made heat-pump water heater.)

    That said, you probably don't want a heat-pump water heater. All heat-pump water heaters are noisier than electric-resistance water heaters, and it makes no sense to install a heat-pump water heater beside the bedroom of a light sleeper.

  2. Mark_Be | | #2

    Have you looked at these? It is a split system - only the tank is inside.

    https://www.sandenwaterheater.com/

    1. Calum_Wilde | | #3

      You'd need to be using vast amounts of hot water to ever recover the cost of one of those. I'm also really curious if the rated COP includes the power required to run the heat trace between the house and the compressor outside.

      1. morebry | | #18

        I am not an energy expert but I found this 2013 energy study funded by the Washington State University Energy Program on just what you are talking about. There is nothing more recent. If you know how to read these numbers, I would really appreciate any input. I am in the market for the SanCO2.

        1. Calum_Wilde | | #19

          That study appears to use a preproduction (for the north American market) model and makes no meansion of heat trace tape. Unfortunately I don't think we can draw any valid conclusions about energy efficiency from that study.

  3. user-6798160 | | #4

    Thanks very much for the suggestions. I did consider the Sanden heaters, but we don't have room for the outside unit on that side of the house. I think I'll just get a really good drain water heat recovery device and be happy with that and an electric resistance heater.

  4. NormanWB | | #5

    Rheem claims their units are about the same noise level as a whisper. Bear in mind, that the heat pump only runs when it needs to, so it may not be a problem. You could get a white noise machine to mask the sound, if it is an issue.

  5. user-626934 | | #6

    The newer Rheem units are significantly quieter than any other packaged HPWH on the market. The Steibel Elton units are not particularly quiet, in my opinion...middle of the road compared to others.

    https://www.rheem.com/group/rheem-hybrid-electric-water-heater-professional-prestige-series-hybrid-electric-water-heater/

  6. GBA Editor
    Martin Holladay | | #7

    John,
    Thanks for your comment -- I appreciate your experience on this matter.

  7. InverterGuy | | #8

    Update. Happened to read this question looking for A definitive answer on the quietest question . I can tell you the Rheem and Ruud In my opinion are no longer quiet. I have installed dozens of the Gen 4 Only a few manageable noise complaints. I have installed six of the new GEN five in the last three weeks every customer is complaining. I will no longer buy these.
    They re-engineered the cabinet for some reason and the frequency sound of the fan is extremely annoying. I am having to go to extremes to sound dampen The areas around these units. Also had had to vent a couple that normally would not have had to. That equals extra time to make people happy., these have significantly affected my profit margin.

    1. aunsafe2015 | | #9

      Where are the units located that are getting noise complaints? Just curious if we are talking about say, a closet right next to a bedroom, an attic, etc.

    2. charlie_sullivan | | #10

      Thanks for the report. That's unfortunate. Do you have a new go-to option now that you are turning away from those?

    3. BenVB | | #21

      I just had an 80 gal Rheem Proterra Gen 5 installed this week. Very noisy - it's in the basement and I can tell when it turns on from the other side of the house upstairs. Mine was manufactured 19 Feb 2021. I will be calling tech support to get in line for the retrofit kit. The noise is a combination of buzzing/resonating fan and higher pitched compressor noise. I can't imagine anyone putting up with this much noise if they have a bedroom nearby. It's tolerable for now for since all our bedrooms are on the opposite side of the house.

      The app is cool though ¯\_(ツ)_/¯

      1. kieran973 | | #24

        Same here. I had the 65 Gen 5 installed in January in our basement. We can hear it everywhere on the first floor and we can even here it in some parts of the second floor. Is there actually a noise-dampening retrofit kit?

        1. BenVB | | #29

          One thing I did that helped a little bit was move the water heater a half inch so it wasn't in contact with the wall/framing. It was transferring some of the vibration/noise directly to the structure of the house.

  8. InverterGuy | | #11

    No I am searching for some data trying to figure out what’s available to me that is going to be quieter. The problem is the ream and Ruud are the ones that the utility programs here like most.
    I have a problem and that we’re dealing with right now we’re going to put the vent adapter and run a duct out the side of the house. Which is another thing they used to have a built-in vent adapter now you have to buy a new one it’s 100 bucks. The worst part is the customers are blaming me for this LOL All part of being in business I guess.

    1. sorka95032 | | #20

      Have you had any luck finding an alternative? Also, have you been in contact with Rheem about the issue. I saw another post where a customer claimed Rheem told them they're aware of the issue and that they're engineering a fix for this.

      I was all set to get the Rheem as it has the efficiency and the remote app features I need but then started reading about noise complaints. Since I plan to duct until the central hallway between all the bedrooms to take advantage of the cooling, it would be unfortunate if it was loud enough to hear in the bedrooms. Also, the actual unit location would be on the other side of my daughters closet but on the outside. The water heater closet is exterior so there's an insulated wall there but the water heater is literally pushed against the back of the wall in the installation closet.

  9. Expert Member
    BILL WICHERS | | #12

    Cabinet design changes probably mean you have a resonance. I've had to deal with that with transformers in commercial buildings ocassionaly to. Try my method to quiet the unit down:

    While the unit is running, run your knuckle over the surface, pressing as you go. You're looking for a spot where pressure makes a noticeable change in the noise, sometimes quieter, and sometimes changing the pitch. That's a critical spot. When you find that spot, you can do one of two things: 1- stick a big round magnet there to add some mass, or 2- what that spot with a small bullnose-type hammer to dent it.

    All you need to do is to deform the material a bit to change the resonance. I've been able to make BIG differences in transformer noise by doing this to the sheet steel chassis, so it might work for you too. Anything further would require modifying the unit itself, which is almost certain to void the warranty. If you're not worried about the warranty, try using vibration isolators on the fan mounts, and adding some MLV (Mass-Loaded Vinyl) sheet to the inside surfaces of the enclosure. The MLV sheet is made for sound dampening, and it can be "installed" with a spray adhesive.

    Bill

    1. brian_wiley | | #14

      Hi Bill, that’s an interesting suggestion about the MLV. Have you ever tried that on any of your transformers with any success? My only experience has been is quieting down panels in old automotive restoration, but it seems like it’d work well for dampening the hum of my AO Smith.

    2. rondeaunotrondo | | #16

      That stuff isn't cheap, how big of a magnetic would work Bill? See my comment below.

  10. willymo | | #13

    If the issue is noise sleeping (eg. the OP's question) the easiest thing to do is just turn it down (or off at night, then back up (or on) in the morning. Easy to set up a schedule to do this.

  11. Deleted | | #15

    Deleted

  12. rondeaunotrondo | | #17

    I just had a Rheem Proterra 65L HPHW GEN 5 purchased at HD installed 2 days ago in our open unfinished basement. When it turned on I thought it was quiet but after 24h I was surprised how loud it was when I was in the basement. Db is approximately 55 standing next to it and 65 db 2inches above the HP. I tried to see if something was rattling but it’s def the pump on the top of the heater. Although in the end, we can barely hear it up stairs and have to be really listening to it. It also rarely runs though with a house of 4 (likely oversized).

  13. acrobaticnurse | | #22

    I wonder if the rheem can be programmed for electric resistance heating only at night and if that would be much quieter.

    1. BenVB | | #23

      Hi Eli - yes not sure if the app is the same for the older 4th Gen but on my Proterra 5th Gen you can schedule the operation mode. I haven't tried to set it up personally since I am in Heat Pump only. But from looking at the app you should be able to set it up for resistance only during whatever hours you specify. Ours runs very little outside of morning shower recovery.

    2. willymo | | #26

      Eli, you can co that, but much easier is just turn up the heat in the evening to 140, then down to 110 for the night. You won't hear anything, because it won't come on. Leave it on heatpump only.

  14. kieran973 | | #25

    I have the 65 gallon Gen 5. Very noisy and runs probably 18 hours a day. It's in our unconditioned basement, but we can hear it everywhere on the first floor and in some rooms on the second floor. Averaging 6 kwh per day and we leave it in heat pump mode 24/7. Two adult showers, one toddler bath every day, vigorous/over-the-top hand-washing, 3 loads of laundry per week, one dishwasher load every other day. I just had our rim joists and crawl space walls insulated to R-15 and this made no difference in average daily usage. I don't really mind the seemingly high usage (others have reported 3-4 kwh per day) since we have solar, but it would be nice to do something about the noise. So if anyone hears anything about a noise retrofit, please let us know. Thanks.

  15. Dugdale | | #27

    I installed a Gen 5 about a month ago myself in my basement and yes it is noisy. It is not the same noise as your refrigerator as I had hoped, mine has a nasty peak at 200 Hz, that frequency is about 15dB above all the other frequencies which makes it more annoying because a refrigerator has equal energy across the frequency spectrum which gives it a more "pleasing sound". I measured my unit at 62dBa 1 meter from the unit, but I am getting 53dB at 200Hz in the floor above the unit (see pic). 53dB might not seem bad but since it is only at one frequency it does sound annoying to me. Years ago I was a sound engineer and one of the things I had to troubleshoot was 120Hz hum in sound systems, so my ears are tune to that frequency and 200Hz is not far from 120Hz hum. That being said my wife has never said anything about it.

    I tried adding Rockwool Safe and Sound around my water heater walls (see pic) but that only help reduce the 200Hz by 1dB which it what I figured would happen, but I wanted to try that first.

    Next up I plan on taking the top off the unit and adding a better sound blanket around the compressor, I called Rheem about this but I was on hold too long, but I read the warranty and it does not say I can't. See the pic and notice how the top of the compressor is exposed. I will update this when I have made the fix and will report back with my measurements.

    Beside the noise it works great and is really cheap to operate.

    1. bbison | | #33

      Any updates on your noise dampening?
      I also installed a gen 5 last week and the 200hz tone is LOUD. Contacted Rheem and they seemed to know about it (tech mentioned that frequency specifically) so will swap out for another unit, from a different build date.

      Curious if anyone has a Gen 5 that does NOT make this noise?

      1. kieran973 | | #35

        Hi bbison,

        I’m curious about the cost of exchanging your Gen 5 unit. What if anything is Rheem charging you for this? What if anything is your plumber charging you for labor? I also have a loud Gen 5 (installed in January) that I assumed I would just have to live with.

        1. bbison | | #36

          It is under warranty so all costs covered. Call the service line and they will walk you through a diagnostic then generate the paperwork and schedule the authorization for service
          (800) 995-0982

      2. Dugdale | | #37

        Sorry it has been awhile. I didn't work on the noise issue but I worked on vent the exhaust to my crawl space, after I did that I noticed the sound was better, so when I measured 200Hz at the locations I tested before I noticed an 8dB improvement. As you can see in the image I also added insulation to the duct work which might have helped. Now I am thinking I should duct the intake as well.

  16. rondeaunotrondo | | #28

    Great insight. The “resonance” from the compressor is what I hear on our 1st floor and is bothersome although used to it at this point. I wondered about rock wool. Also waited too long on hold. Please report back a fix if you find one.

  17. bigred | | #30

    I don't know if there is a huge difference between the Gen 4 and 5, but I have a 50 gal Rheem I installed in January of 2019. It is in my Garage in Central Texas (so hot most of the time) and adjacent to my Master bedroom. the noise can be heard in the garage, but is not a problem in the bedroom. Maybe the heater gets drowned out by the HVAC blower that is directly adjacent to the water heater in the garage, or the Gen 5 is a lot noiser.

    1. rondeaunotrondo | | #31

      Gen 5 is known to be louder unfortunately.

  18. user-5574861 | | #32

    I have the Gen 4 in my basement directly below the kitchen and I can only hear it when I am in the basement. I can, however hear the condensate pump from my kitchen when it runs.

  19. bbison | | #34

    Does anyone have a Gen 5 unit that does NOT make this steady tone (200hz)?

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