@elton I shared the link.

Posted by: @jamespa

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So they did (or at least say they did) measure it inside.  Have you reason to doubt them?

As I said, Table 2 shows NR35+ just outside the window of their bedroom. The assessor might have measured NR23 in the bedroom, but it does not mean that a higher NR had not been measured. An NR35 just outside the window can not be reduced to NR23 with an open window. 

Posted by: @persephone

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My main issue, however, is the 'condition'. Apparently, the 'predicted sound pressure levels' is 42dBA. But what is the 42dBA? Is it a criterion specific to MCS, a PDR criterion, or just a general noise/nuisance criterion? If 42dBA is an MCS criterion or a PDR one, can it be used as a condition for an ASHP that needed a planning permission because it is non-compliant with MCS and is not a permitted development?

Where in relation to your home is the offending heat pump?

To my understanding the 42dBA criterion referenced in the condition for the ASHP noise level is likely aligned with general noise regulations or guidelines rather than being specific to any single standard like MCS. This level is commonly used to assess the impact of noise on residential amenity and to ensure that noise from installations like ASHPs does not constitute a nuisance to neighbours. While MCS standards do include noise considerations, the 42dBA level as a condition for planning permission seems to be more about ensuring the ASHP's operation does not adversely affect nearby residents, regardless of its compliance with MCS status. If the ASHP required planning permission due to non-compliance with MCS standards or because it's not considered permitted development, using a noise criterion like 42dBA as a condition aims to protect residential amenity by setting a maximum acceptable noise level.

Some initial observations:
- In my opinion (personal experience and speaking to a heat pump engineer) Samsungs like that are a bit rough. Not a Vaillant or Weissman - not a quality choice. Known to be a bit more noisy. Clattery beasts.

- Its at an angle which will lead to bearings wearing and it being noisy (I think i'm right in saying left/right is worse than forward/back)

- Is it on rubber vibration mounts? Is vibration causing the noise?

- Could it be air moving through ducting in the yard causing noise too?

Posted by: @persephone

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@jamespa I don't have evidence of measurements in my house. What I am trying to say is that NR23 in my neighbour's house which is a new building with good insulation, has nothing to do with the NR in my house. NR in one property can not be used to 'predict' the NR in another property. 

NR has a curve system. So, a 4 decibel decrease does not mean a 4NR decrease. 

So without any evidence, on what basis are you questioning the conclusion reached by WSP (on which the LPA must base their assessment unless there is concrete evidence to the contrary)?  WSP clearly give a measured value for the level of noise in your neighbours house which is below the planning condition and from that and the additional distance infer a value in your house which is well below the planning condition.  Unless you invited them into your house to take measurements inside, that's all they can be expected to do, given that they have no right of entry. 

Given that the value that results from this calculation is well below the value specified in the condition, there is margin for error, further strengthening the position of your neighbour and the LPA in accepting the report at face value.  Sure there are differences in house construction, but unless there is reason to believe that this makes sufficient difference to bring the inferred value above the level demanded by the planning condition, that will not (and cannot) be factored into to the LPAs assessment.  

Posted by: @persephone

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Another issue is the positioning of the ASHP which is on the boundary of their house with a public path. I have not seen any legislation that approves of installation of noise/smoke generating devices on the boundary of houses in residential areas. 

The legislation which approves the positioning is planning legislation.  Its development, it requires planning consent, it has planning consent (ASHPs don't generate smoke btw), end of.

Unfortunately, based on what you have said here, it looks doubtful that you have a case.  Do you think you could convince a judge that your neighbour is 'substantially and unreasonably affecting the enjoyment of your property' or causing damage to your health?  Are you convinced that this is the case?

Posted by: @editor

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Posted by: @persephone

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My main issue, however, is the 'condition'. Apparently, the 'predicted sound pressure levels' is 42dBA. But what is the 42dBA? Is it a criterion specific to MCS, a PDR criterion, or just a general noise/nuisance criterion? If 42dBA is an MCS criterion or a PDR one, can it be used as a condition for an ASHP that needed a planning permission because it is non-compliant with MCS and is not a permitted development?

Where in relation to your home is the offending heat pump?

To my understanding the 42dBA criterion referenced in the condition for the ASHP noise level is likely aligned with general noise regulations or guidelines rather than being specific to any single standard like MCS. This level is commonly used to assess the impact of noise on residential amenity and to ensure that noise from installations like ASHPs does not constitute a nuisance to neighbours. While MCS standards do include noise considerations, the 42dBA level as a condition for planning permission seems to be more about ensuring the ASHP's operation does not adversely affect nearby residents, regardless of its compliance with MCS status. If the ASHP required planning permission due to non-compliance with MCS standards or because it's not considered permitted development, using a noise criterion like 42dBA as a condition aims to protect residential amenity by setting a maximum acceptable noise level.

For what its worth I asked MCS a few weeks ago where the figure of 42dB (which does appear in MCS-020 and thus is part of planning law) came from, and what was the justification for it.  They said it came from MLUHC and they didn't have the justification.  So I asked MLUHC and they haven't answered. 

However you seem to be suggesting this figure is also used elsewhere (do you have a reference?).  There is possibly some logic behind this: BS8233 states that a noise level of 30dB(A) or less at night in bedrooms is desirable.  It also states that 15dB can be assumed for the attenuation due to the fabric of a house (ie the difference from outside to inside).  So 42-15=27 which is 3dB below 30, giving a bit of a margin for error.  It would therefore be quite logical to go with a requirement of 42dB(A) outside, to ensure that the inside meets the 'desirable' level for sleeping quarters.  

@jamespa, I don't have a reference for the specific use of 42dBA as a criterion. I was speculating on why the 42dB might apply, particularly in the context of assessing the impact of external noise sources like ASHPs on residential environments. This speculation aligns broadly with the general principles outlined in BS 8233:2014. While it doesn't explicitly specify 42dB as a threshold, as you've also said, the rationale for using an external noise level of 42dB to achieve a desirable internal noise level, considering the attenuation provided by the building's fabric, aligns with the standard's objectives to protect residents from excessive noise. This method ensures external noise sources do not lead to indoor noise levels exceeding 30dBA, which is desirable for bedrooms at night to prevent sleep disturbance. It's a tricky one!

The 42dB(A) figure as I understand it was a government compromise between the CIEH/IoA who were lobbying for lower (they still do - see their professional advice note) and industry who wanted higher. It was a straight compromise between those prioritising rapid rollout and those prioritising environmental health safeguards - not a figure based on evidence or research.

You'll note that in the latest MCS020 they are looking at reducing rural background noise to 35dB(A).

The big 2 recent ASHP noise reports - Welsh Phase 2 and DSNZ are interesting in this regards. The Welsh Govt one states that as of Nov 23:

"Further work is required to determine if the current permitted noise target is adequate to deal with
protection of quality of life, cumulative impacts of multiple units, tonality, directionality,
intermittency and variation in noise generated over the seasons and at different heat loads; also to
better understand and improve the public perception of noise from ASHPs through guidance and
education."

...which basically makes a nonsense of the figure of 42dB(A), or any figure being set in the absence of proper research. The DESNZ report is good and, unlike MCS (and some industry lobbyists) takes into account material factors such as tonality.

Just looking at your installation, it doesn't meet manufacturer's specs as is too close to the edges and back of the sound box (and it is a sound box - its a nonsense to treat is as anything other than top end of Q8) according to the manual. As you have found with other elements, getting anyone in authority to care and do anything about any aspect of a dodgy, harmful installation can be a monumental task - virtually impossible without monolithic levels of persistence, creativity, tenacity and a huge dollop of luck. 

@elton I'm curious to know how "rural" is defined. I would describe my location as "rural" but the background noise in my location is dominated by traffic noise from major trunk road about one mile away and, depending on conditions, wind through the adjacent wooded areas.  Prior to the installation of my ASHP I used the uncalibrated sound meter app on my phone to get an indicative idea of the level of background noise relative to the heat pump's claimed acoustic specification.  They were about the same if not greater under high wind conditions.  Personally I think the only thing that makes any sense is to define the equipment noise level.  Specifying the environment noise level is crazy.

Posted by: @elton

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The 42dB(A) figure as I understand it was a government compromise between the CIEH/IoA who were lobbying for lower (they still do - see their professional advice note) and industry who wanted higher.

Interesting thanks.  Cieh are only suggesting 2dB lower (35dBA as opposed to 37 for the pump alone) unless there is a tonal penalty, which there may be for some pumps but the better ones eg vaillant, Mitsubishi, have pretty smooth tonal profiles.

Posted by: @elton

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You'll note that in the latest MCS020 they are looking at reducing rural background noise to 35dB(A).

I read this in their consultation but it's meaningless at present because they don't say what happens to the 42dBA figure on which their final calculation depends.  If it stays fixed and the assumed background noise is reduced then the heat pump can be noisier.  Perhaps that's the intention but they don't say 

Posted by: @elton

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Just looking at your installation, it doesn't meet manufacturer's specs as is too close to the edges and back of the sound box (and it is a sound box - its a nonsense to treat is as anything other than top end of Q8) according to the manual.

That won't help op though, installation according to manufacturers spec wasn't a planning condition.

Posted by: @noburn

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I'm curious to know how "rural" is defined. I

MCS are suggesting by postcode but inviting other suggestions.  My gut feeling is that this is a bit too difficult to deal with.

@noburn There is a checker associated with the proposal - a postcode lookup tool. Its quite arbitrary. If you are within a couple of miles of a conurbation or built up area you probably aren't rural.

Background noise levels are a toughie. I bought a data logger for £50, it was rubbish. Bought a proper one (class 2) for £200 and it was much better but background varies hugely across a day, week, season. The background level used if EH ever get to doing an assessment is based on things like LAq90min or LAq5min which is basically the lowest recorded sound level over various intervals over a period. Its all very complex.

I think a noise level should be specific and it should be slightly lower than at present. Also that tonality needs to be accounted for. The long and the short is that the heat pump should always be WELL below background noise levels at all times, not on a par or close. 

James, on: "Interesting thanks.  Cieh are only suggesting 2dB lower (35dBA as opposed to 37 for the pump alone) unless there is a tonal penalty, which there may be for some pumps but the better ones eg vaillant, Mitsubishi, have pretty smooth tonal profiles."

Interesting as Persephone and I are both suffering form the AExxxRXY Samsung models. From looking at product literature and the graphs within it, and from listening to it outside my bet is that the Samsungs (which I have come to thin are a bit are cheap'N'nasty) would be whacked quite hard if a tonlaity measure came in (as it should).