@lokisam I am very interested in this issue of Samsungs potentially being noisier than others. Two factors may be at play:

1. Tonality - it is know some heat pumps have coarse tonality which is a particular disturbance factor (omitted from MCS020 but attracting up to 6dB(A) penalty in the British Standards under BS4142. Its a ridiculous omission of MCS020 - CIEH, DESNZ and so many others acknowledge tonality as a key disturbance issue. In essence it means 42dB(A) of a pump with nasty tonality is far worse & more disturbing than 42dB(A)of one without it. Manufacturers should publish tonality charts but guess what Samsung don't, and it needs to be a 1/3 octave chart (not a 1/1) for those techy folk.

2. Sound rating shenanigans - As reported by DESNZ and many others, manufacturers can selectively chose their "highest power level" to be used for MCS020 and it might be false. The ErP label conundrum. Lack of standardisation. Quite a flaw in MCS020 and a reason why it is criticised for not driving quieter heat pumps (as you can just wangle the numbers). From what I read, heat pump suppliers should not use ErP label dB(A) rated figures (Energy Label figures) as they do not represented the actual dB(A) level at full power. I know at least one Samsung model that used the ErP label figure and this can be many decibels under what it should be if consistently reported. Apex did some interesting work in this area for the Welsh Government.

So in short you might have a heat pump that is louder than it is rated, and has tonality that increases the nuisance factor of every dB(A) while not necessarily raising them overall. 

Does anyone else have views on whether Samsungs stand out as particularly noisy? I'm not talking about the latest ones - I'm talking (the larger) Gen 6 which seems to be the issue. As mentioned, I've heard direct from an installer that they are know to be particular noisy, and to have a quality to their sound that can be disturbing (this is the tonality aspect).

Posted by: @lokisam

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Would anyone feel able to comment on whether big rads (tripples) not being hot all the way down after an hour is normal? Smaller rads are fully warm by this point.

That could be the case, depending on where the triple rad is in the circuit. We only have one triple on a 20 rad system, which is in a conservatory. The radiator was added onto the existing heating system by the previous homeowner when he added the conservatory. Normally the radiator is off - we only heat the conservatory when we have guests round for use as a dining space. It takes quite a long time to warm up, even when the rest of the circuit is warm. That's probably because the flow through it is too low, but because the room is only rarely heated that's not an issue. It does the job in there when we need it to.

Out of interest, what is the maximum design flow temperature of heat pump system? Our system is 45degC, but from a cold winter start at 4am, it'll take better part of 2hrs to reach 40degC. That's to be expected, and really we should have it running 24/7 to keep a nice stable weather compensated flow temperature. Her who shall be obeyed wants it turned off overnight however! 😉 Our ASHP is only just man enough for the worst-case winter, and wasn't sized with pre-heat capacity in reserve. We should have a Grant 13kW, but DNO supply fuse issues forced us to drop to a 10kW unit. The 3kW back-up heater energised during defrost helps a lot during pre-heat in winter from a cold start when the ASHP is defrosting periodically. I was very sceptical about that, but I've been proved wrong. The installers didn't bother wiring it up, but had run all the cabling for it. I finally got round to connecting it a year after install!

Our ASHP is noticeably louder when the coil is heavily frosted. That makes sense, as the fan is trying to pull air through almost blocked coil fins, so the fan speed is quite high, and the compressor is also working hard. The rubber crumb base feet are very effective vibration isolators, and accommodate a mounting surface that's a little out-of-level. I doubt adding a gravel bed underneath will benefit you. If you have several reflecting surfaces bouncing sound towards indoors, then you could look at sound installing sound absorbent material (acoustic foam passive attenuator panels) on them. Don't install anything that impedes airflow in or out of the unit however. Some photos of your install would be informative. Have you tried to determine how much noise is being transmitted indoors from your outdoor unit? Is it pipework and system noise transmission or break-in noise from outside through the walls, windows, etc.? A sound level meter app on a phone such as 'Decibel' might help.

@lokisam it is good that you have been able to visit other sites to compare the noise with your pump. I haven't found any other Samsung installations locally and has hoping, perhaps forlornly, that my noisy pump was due to some simple installation or running issue that could be resolved easily, rather than a generic issue with these pumps 🙄 

It will be interesting to hear how you get on with your installer visit and any follow up from Samsung. I will let you know if anything useful comes from my engineer visit - assuming I can get them to commit to a date...

@elton that's interesting about the tonality of the noise. Certainly when the noise from our pump is most obtrusive it is a very harsh, complex sound compared to when it is running quietly.

The other issue is that the frequency is constantly changing as the compressor appears to be revving up and down a lot which is more annoying than a constant noise would be. I guess this frequency variation couples with the harsh tonality to increase the disturbance factor.

It would be interesting to know if others are experiencing these noise issues with the Gen 6 Samsung pumps. I know that @bontwoody replied earlier to say he doesn't hear a peep from his 5kW Samsung, so perhaps it is an issue with the 8kW unit 🤔 

@sjn i felt exactly like you when I heard my colleagues Samsung revving itself up. The first few I looked at were really quiet so I was convinced I just had a faulty one or a faulty install. It may still turn out to be the case I guess. I still hope so. I had the pump running yesterday evening and it seemed (as usual) to get louder after an hour and by bedtime it sounded like a van idling and i was relieved to turn the thermostat down and go to bed. I am currently just using it on manual. I do wonder if the revving up and down is related to settings or the interaction with the thermostat. This morning it did a water heating session at about 6 which woke me up. After reading your description, I sent a more detailed description of my noise problem to the installers. Fitters are going to put acoustic insulation under the tank. I have been clear that the noise from the outside unit is too loud inside but they haven't offered any solution about that. The boss (who has not been on site since quoting - his son does the installation) did say some people are more "finicky" than others sound wise! I love the way he presumes I'm the problem without even hearing the unit. I think the pump will have to move. Even if it can be made to run quieter, it is so close to my patio doors, I think I will always be able to hear it. I feel foolish for just presuming it wouldn't be heard inside but also surprised that nobody pointed it out. Once my fitters have had reasonable chance to address the issue, I will get a second opinion and let you know. By the way, you might find a pump to visit through this scheme.

It's a great scheme but I won't be inviting anyone to view mine yet. It's not a good advert. 

Thanks @lokisam 

We've been lucky over the last week with day temperatures in the 20s and night temperature only down to 11C so haven't had the heating on. The previous week it did drop to 3C on a few nights so I was woken up when the heat pump came on around 6am to warm up the tile floor in the shower room 🙄. I have the hot water set to run at 3pm as our tank can hold the heat charge - it avoids the noise of overnight runs, especially when it's really cold and the DHW run triggers defrost cycles.

I know I have been aware of the sound of gas and oil boilers in previous houses - maybe I'm one of the "finicky" type - but I did presume that the ASHP would be no worse.

Thanks for the link to the Visit a Heat Pump scheme. Unfortunately it is only offering 3 "local" hosts and they are between 80 and 240 miles drive! I'll keep an eye on the site to see if anymore come available and also ask around locally.

@sjn 

I just had a very interesting saunter over to the visit a heat pump site. Spent a very boring 20 mins looking through 100 pumps coming up from my postcode outwards. Now, lets start with this post: The Most Popular Heat Pump in the UK: Is It In Your Home? - Renewable Heating Hub. I think this is a decent bellwether for what brands are out there and states that:

- Mitsubishis are most popular - 20% of owners have one.

- Samsung, Daikin, Vaillant each have around 15% of the share.

So lets compare this with 100 owners on visit a heat pump - what owners want to show off, looking at the brands above:

- Mitsubishi 18%

- Vaillant 11%

- Daikin 9%

- Samsung 4%

- Unknown (no pic or description) or other (Panasonic, LG etc) = (58%) 

I must say, I find that rather interesting. Perhaps reflective of customer satisfaction and reluctance to show the unit off, including.... noise factors?

@elton that's quite an intriguing comparison. It reflects the trend we've observed with Ecodan owners here, where questions usually revolve around minor tweaks or small issues. In contrast, Samsung cases on the forums tend to present more dire situations. Having said that, I wouldn't go as far as labelling Samsung units as rubbish, even though I am tempted because I've seen a massive decline in the quality of Samsung products – I'm not going to complain about our Samsung fridge again. It seems more like a case of incompetent installers, whereas Mitsubishi has evidently done a better job of ensuring their installers fit their heat pumps properly.

@elton that's a cunningly devised methodology 😀 . As a self selecting group the visit a heat pump list will probably give a very accurate reflection of levels of satisfaction - I would certainly not want to show off my choice of system in its current state.

The prominence of the Mitsubishi Ecodan in both groups is quite galling for me. Our first choice installer is Mitsubishi Accredited and was going to fit an 8.5kW Ecodan but, due to Covid site access restrictions at the time, we changed horses mid-build and had the Samsung installed by the plumber who was already on site.

I wish I'd had more time to research things back then and, indeed, known that so much research was actually required.

Thanks @mars and @sjn  

I ran another check of 100 based on the NW1 postcode (different to mine) and came out with: 

- Mitsubishi 23% - Yes rules the roost!

- Vaillant 14%

- Daikin 16%

- Samsung.... 4% (with half/two of these looking to be newer units - not the series 6).

I may have crossed over with some hosts as apparently, according to the website there are only 200 but NW1 is a long way from me so there will be many in there that I didn't count in my previous check.

As well as Persephone and me both suffering noise issues from Samsung Gen 6 units (from neighbours), added to the comments on this thread about them, added to a reputable installer saying to me they are quite noisy, and the %s above, I think yes it could be down in part to it needing more care during installs but I just can't help but think, esp. with the figures above that a fair few are quietly (noisily!) disliked by a chunk of owners. 

The more I think about it @sjn the more it feels like a fair test of satisfaction. If you invite folk to come and visit then you are going to be at least reasonably happy with your unit.  

@editor yes, the more I read the forum posts the more I realise that the Samsung issues tend to be the more challenging sort.

The various manufacturers certainly appear to have very different relationships with the installers.

With my install, the Samsung unit was supplied by Joule as a package with a pre-plumbed tank; Joule were partnered with an MSC accredited business (in Devon) to do all the compliance paperwork; the actual installation was done by the plumber who was already working on our new build; and the commissioning was carried out by another independent plumbing business from Inverness. This is a very long chain of responsibility (which I wasn't aware of until after the event) that raises the question about how much oversight and control there is to ensure the heat pumps are fitted properly.

I have seen an interesting and recent case on Facebook's "Heat Geek's Heating Help for Homeowners" where an 8kW Samsung (appears to be an AE080) has been ordered to be removed in Aberdeen for noise issues. From what I've read it passed MCS but failed an Env. Health noise assessment. Another Samsung Gen 6 noise issue to add to mine, the ones in this thread, the comments from the heat pump installer I spoke to and a curious absence of them on Visit a Heat Pump. 

I would be very interested to hear if any other installers are aware of issues with Samsung Gen 6's - whether it be about general loudness or tonality - or whether they feel Samsung Gen 6's are comparable noise-wise with Mitsubishis, Vaillants, Daikins etc?