@odynsfee 

I'm thinking the problem may well stack back to noisy compressors on these Gen 6 Samsung units. Might be a batch or widespread - i'm not sure. Many say theirs is "quiet" but I am not sold on that to be honest.

Anecdotally, they are known to be loud units compared to others - even installers tell you that [unless perhaps if some don't want to admit as they've installed many :-)]. Barely anyone wants to show them off on visit a Heat Pump. If they are louder than they are rated (and I believe some units are eg Vaillant defrost) then the unit has been essentially mis-sold & it is a manufacturer's design fault - they should rectify it. But they wont as can hide behind the forced position that noise is a "myth".

I do wonder whether (if it is ground mounted) you are suffering not just from the circ pump but from fluid resonance from the dreaded Gen 6 compressor. That means vibration from the compressor travelling in the fluid (or in the copper of the pipes themselves), possibly being amplified by the circ pump (this can happen) then vibrating into your structure. Is the noise all the time when the unit is running? Does the most prominent tone of the unit sound like the noise inside? Can you hear vibration in any structural elements - beams, walls etc (may be in one but not another). Fast flowing, wider pipework carrying vibrations in the fluid that then manifest into the structure as a whine.

@elton I think that you are correct about the noise coming from the compressor and the water resonance that is in the pipes is the same sound as the unit itself .

I have boxed all of the pipe work in for aesthetic purposes and I was hoping that it would dampen the whining noise at the same time, I stuffed a load of sound insulation in as well for good measure but I can still hear it .

When the pump is not working hard the noise that’s coming from the pipe work inside cancels out the external pump sound so it’s definitely water/copper pipe borne.

The noise is in the air and it’s hard to pinpoint exactly but when you put your ear to the boxed in pipes you can hear the whine and the water coursing through them. I have tried all of the pump settings and the lower one’s do help but it’s generally its still quite annoying.

i can’t say that i can hear any structural vibrations.

@odynsfee 

Thanks. A couple of things spring to mind. Where the pipes enter the building - do they touch brick? Inside, are they anchored to walls/beams etc? 

Fluid resonance can be amplified by circ pump and bends in pipes, and of course speed (HW). The issue is incredibly poorly known about yet will affect quite a few I should think esp as small pipes are being replaced by larger pipes with fast flows driven by powerful compressors - into mostly aged structures that themselves have all sorts of hollows & materials that themselves resonate at frequencies that compressors put out (around 50-100 hz). The noise may appear in pockets around your home where the resonance noise becomes airborne then pools in corners and hollows as low frequency noise does.

Does the pattern of sound differ when its very very cold? eg less than 3 degrees and the compressor switches to shouty mode?

I believe at least some Samsung Gen 6 compressors have a design fault (much like the Vaillant defrost cycle issue), resulting in course fluid resonance and loud airborne noise. As noise issues are incredibly sensitive to raise in the industry - the raising of noise issues has met with resistance and denial because they are such a risk - they are it seems ignored. Airborne noise, vibration noise, fluid resonance noise - many paths but all too often ignored or denied.

Just to add, it does sound like in your case the fluid resonance is transferring into the structure or coming from pipes and... importantly in both/either case... then getting airborne from that point as a low frequency noise (LFN) - and LFNs in a standard British home can be a nightmare with materials, angles of walls, hollows etc amplifying them and crating pockets even as far away as you can get from the unit. It can be bad enough with windows resonating at the frequency of the heat pump from airborne noise outside, let alone this happening from inside. 

The solution overall is for compressors to be quieter, both dB(A) and tonality wise (which would benefit outside noise and no doubt improve vibration), but there is no incentive for manufacturers to improve compressors. In fact less so under the new proposed MCS which steers us towards greater risk from noise affecting rollout. 

Just want to say I've done an experiment with mine. I have recorded the sound of the unit on my phone and played it back outside through a speaker sat on insulation on top of the unit to the same db reading. It's not as loud inside but you can still hear it, so at least some is coming in through windows (patio doors). I had to play the recording at 42db to eliminate all internal noise. Currently my heat pump varies between 46 and 56 - and it is mostly a compressor noise. Engineer coming again next week and I'm still hoping he will find a fault. I totally agree that issues with noise are denied. All over the Internet there are claims that they are quieter than a microwave, about the same as a fridge. I told Samsung I was getting 56db and they said it was within normal range so not considered a fault.

At this point I would like to observe that the flue fan from my gas boiler was very distinctly audible in parts of the house, as at times were some of the water pipes.  Im not sure that there is a silent way to heat, other than resistance electric (although even that can hum at 50Hz!)

Im not trying to 'play down' noise from ASHPs, just to point out that other technologies for achieving the same also make a noise.  I can (just) hear my own ASHP when its defrosting, although the fridge (another heat pump) is noisier and the TV noisier still.

Resonances can be particularly annoying however.  I presume you have flexible pipework on the outside between the ashp and the house and that where it passes through the wall it is properly insulated so pipework doesn't touch the structure of the building at this point.  Boxing in can of course make things worse although the sound insulation should help.  There is sound insulation and sound insulation BTW, to suppress low frequency sound you need heavy stuff not just some loft insulation.

@jamespa Hi, yes I have flexible pipework. Following an inspection, the installers were required to sleeve and insulate the pipes where they pass through the brickwork. I don't think they've done it well because it twangs on start up, but mcs seem satisfied. My outdoor unit is on my patio outside my living room. And the tank is in the loft above my bedroom. So I have constant noise in the living room and bedroom when it's running. It's the noisiest form of heating I've ever had, and the entire Internet (except the Daily Mail) insists heat pumps are really quite quiet these days. The point is, in my case, it is not all due to pipework. Some of the noise is coming through double glazing and this wouldn't be the case if the unit was a bit.quieter. Some units are quieter but as mcs standards don't have any rules about noise nuisance to homeowners, there's nothing I can do about it. In the words of my installer, "If you don't like the noise, that's just tough titty!"

@jamespa A boiler flue letting out steam and radiator pipe noise is very different to compressor resonance and heat pump noise. These are low frequency penetrating, vibrating sounds. There is debate as to whether the dB(A) scale is even appropriate for such sounds. Plus, as CIEH quite rightly say, there is the issue of tonality with heat pump noise that comes with compressor noise and resonance. Comparisons with fridge noise/TVs etc are not valid IMHO. They are not 16kW units with large rotating parts bolted into a wall with large, fast flow pipework running across a home to/in bedrooms etc, bolted high upon a wall (vibration risk) casting low frequency noise at potentially over 76dB(A) within 5cm of neighbouring gardens (permitted under proposed revisions to MCS) in quiet suburbs. 

We are retrofitting our old housing stock with large, high powered outdoor units capable of airborne noise, vibration and fluid resonance issues as they interact with our more densely packs, less modern housing stock and it does not get taken seriously enough as a risk (possibly because it represents such a risk & it is hoped somehow it will evaporate with newer, quieter units despite older units that will continue to be fitted for at least a decade).

@lokisam Can I suggest checking replacing the (black rubber) seal on your double glazing? This worked to some extent for me. Low frequency noise penetrates perished rubber seals - unlike boiler flue noises. It can also resonate at the frequency of your double glazed window (again - a boiler flue wont) amplifying the noise. And whether through the window seal/gap, vibrating the window or fluid resonance in pipes, when LFN gets in it pools in corners,  bounces off surfaces and amplifies, amplifies in hollows etc

It can be a nightmare - can appear over the other side of your home. Thick curtains, new rubber window seal, AC150 caulk around the edges and seal any other gaps may be the best strategy short of a class action against Samsung to replace noisy compressors.

Posted by: @elton

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A boiler flue letting out steam and radiator pipe noise is very different to compressor resonance and heat pump noise.

All I was saying is that my gas boiler was louder than my ASHP (the latter is 30cm from a window to the room in which we spend most time) and no less annoying.  Both are quieter than my fridge, which frankly is annoying.

Posted by: @elton

[fridges] are not 16kW units with large rotating parts bolted into a wall with large, fast flow pipework running across a home to/in bedrooms etc, bolted high upon a wall (vibration risk) casting low frequency noise at potentially over 76dB(A) within 5cm of neighbouring gardens (permitted under proposed revisions to MCS) in quiet suburbs. 

Im not sure many people put 16kW units on a wall and Im not sure where 76dB(A) comes from as the max allowed under PD is 37dB(A) at neighbouring property.

Posted by: @elton

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We are retrofitting our old housing stock with large, high powered outdoor units capable of airborne noise, vibration and fluid resonance.  

capable, but rarely reported.  Im not saying never reported but its relatively rare.  As I said my gas boiler caused fluid noises so, whilst Im not defending it, its not new either!

Posted by: @elton

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it is hoped somehow it will evaporate with newer, quieter units despite older units that will continue to be fitted for at least a decade).

I do get the point about older noiser units and do agree that there should be some requirement for heat pump installers to consider and advise the noise in the homeowners house not just the neighbouring house.  

I think you are somewhat over-egging the problem.  Im not saying it doesnt exist nor that it shouldnt be tackled, but to make it out to be quite so bad is going against what appears to be happening on the ground for the most part.  Almost everything we do has consequences, which we mostly have come to accept.  Should we ban cars because of road noise?

As a matter of interest what do you think we should do to heat our homes without overheating the planet?

Posted by: @lokisam

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@jamespa Hi, yes I have flexible pipework. Following an inspection, the installers were required to sleeve and insulate the pipes where they pass through the brickwork. I don't think they've done it well because it twangs on start up, but mcs seem satisfied. My outdoor unit is on my patio outside my living room. And the tank is in the loft above my bedroom. So I have constant noise in the living room and bedroom when it's running. It's the noisiest form of heating I've ever had, and the entire Internet (except the Daily Mail) insists heat pumps are really quite quiet these days. The point is, in my case, it is not all due to pipework. Some of the noise is coming through double glazing and this wouldn't be the case if the unit was a bit.quieter. Some units are quieter but as mcs standards don't have any rules about noise nuisance to homeowners, there's nothing I can do about it. In the words of my installer, "If you don't like the noise, that's just tough titty!"

Im sorry to hear about the problems but its good that you have insulated flexible pipework, albeit only after a rework (which is itself suspicious).  Lets see what we can work out with a bit more information in case that points at solutions:

Im guessing this is the Samsung Gen 6 product (grey) which is quite old and relatively noisy?  Can you tell us what model and also about your house (floor area, construction). 

Twanging on startup is odd, any idea where that is coming from or can you describe the noise more (how long does it last, low or high frequency etc)

If the heat pump is oversized, which is quite common, running it in low noise mode might be an option at least most or some of the time.  Are you in all day every day?  Whats the noise like during the daytime at present when its relatively warm.  Do you run it 24*7 with any TRVs and thermostats set at least 2C above the desired temperature, and have you adjusted the WC curve down to the lowest possible consistent with keeping your house warm>

What is the route taken by the pipes from the heat pump to the loft?

Is the noise you are hearing (so far as you can tell)

• compressor noise (quite tonal, low frequency 50-100Hz - 50Hz being the same frequency as mains hum)
• fan noise (white noise - ie no noticeable tonality)
• noise of water in pipes (a rushing sound)

Distinguishing which might help point to solutions.

I do agree that installers should calculate noise for the homeowner as well as neighbours.  There shouldn't IMHO be a law about what level it needs to be, but there should be a requirement to calculate it and advise the homeowner.  

@elton Not sure if the pipes actually touch were they pass through the walls as holes are sealed with mastic on entry and exit but I could explore .

You are spot on regarding the circ pumps amplifying the noise as the noise being emitted from the heat pump pipes is the same noise that’s being produced after the secondary pump but even louder.

I have noticed that when the pump is working hard i.e it’s below 3c the compressor is so loud that it almost drowns out the internal noise but as a matter of interest when the pump is just ticking over it is obviously quieter but the internal noise is still loud , if that makes sense.

i am finding this issue all consuming to be honest and I’m not sure if it will ever be resolved but I won’t be giving up trying quite yet.