That is interesting, as one of the main reasons I went for an Arotherm plus was the fact that the noise levels are incredibly low and the unit itself is Quiet mark approved. Not sure exactly which model they are looking at but the below might help?

https://www.quietmark.com/brands/vaillant

@dchilton, this is a new one for us too. 

In response to the original question, the heat pump will run almost 24/7 from November to Feb/March if you are to get it working as efficiently as possible.  The other question we have is how far will be from the position that the heat pump is placed to the nearest neighbour.

I'm also quite curious as to which council it is that is in question.

@dchilton Wow, my Arotherm Plus really is as good as silent, I generally know it is on when I get a blast of cold air.  It is far, far quieter than the oil boiler it replaced (and whole lot less smelly).  Original post though is about an Arotherm perhaps (not Plus, there isn't a 15kW machine in the Plus range) - they might be noisier

If you look at the sheet in my signature from Freedom Heat Pumps it does have a sound MCS calculator. However it doesn't have that ASHP. If you know the details you can probably just add it into the sheet.

@witchcraft, yes, its a possibility (hence saying not sure what model they are using). Had a quick look though and even the previous gen Arotherm 15kw is listed as 65-66 dB ( https://www.vaillant.co.uk/specifiers/products/arotherm-air-source-heat-pump-53824.html) and is quiet mark approved ( https://www.vaillant.co.uk/downloads/product-brochures/arotherm-brochure-2006193.pdf). Also, the given levels I am not sure are at what distance (for the plus they provide levels at various distances from the unit in the literature). Vaillant may be able to provide additional data on that as they list it being tested in accordance with an EN/ISO standard, so there should be data available to substantiate the claim which may be available on request.

Again, not 100% this is the same model as they are using, might be useful? 

Suppose in conjunction with @mars comment, yes it will run almost constant for those months, but realistically those are not months of the year that many of us plan to spend lounging in the garden, so the direct impact to neighbours would be minimal I would think

@dchilton Also even if on 24/7 it isn't going to be running at full chat all of the time, mine is often barely on with the fans turning very slowly indeed.

I assume there is a reason for the council to be involved?  Does the unit exceed permitted development reg’s? 

Does the council have guidance on acceptable noise levels at different distances? You could check yourself using an app on your phone and measure the decibels at different distances.

Planning portal.

https://www.planningportal.co.uk/info/200130/common_projects/27/heat_pumps/2

Thanks for all the replies, the following are the specific and technical points raised:

Dear Mr and Mrs ....

Thank you for your e-mail below received earlier today. I can attend a meeting if required but I would want to establish beforehand the specific points that the meeting would be intended to consider. I suggest this, not least because, once we set out the points it may become apparent that we can actually resolve the points line by line simply by exchange of e-mail. I have been to the property and seen the layout including in relation to the neighbouring property and I have seen the heat pumps at the nearby bungalows.

The issues as they present themselves for the Planning assessment are technical and specific.

The points I think are these:

1) Certain renewable energy schemes are ‘permitted development’ under Part 14 of the GPDO(2015)

2) Part 14 Class G deals with “installation or alteration etc of air source heat pumps on domestic premises”

3) Paragraph G.1 says “Development is not permitted by Class G unless the air source heat pump complies with the MCS

Planning Standards or equivalent standards”.

4) “MCS Planning Standards” is defined at Part 14 P and means: “the standards specified in the Microgeneration Certification Scheme for air source heat pumps (being MCS 007). Footnote 140 refers, specifying the version of the MCS to be used: “Version 2.4 dated 16th December 2013, an electronic copy of which can be found here: http://www.microgenerationcertification.org/mcs-standards/product-standards/10-mcs-standards/126-product-MCS 006 standards-2 and a copy of the MCS Planning Standards may be inspected at the Department of Energy and Climate Change, 3 Whitehall Place, London, SW1A 2HH.”

5) Other GPDO Part 14 Class G criteria relevant to consider: G.2(d) the volume of the air source heat pump’s outdoor compressor unit (including any housing) would exceed 0.6 cubic metres; [ie. not pd if the size of the unit exceeds 0.6m3 – I am not sure the details have been given but the size of the structure is not an issue in this case in any event.]

6) G.3 sets four conditions (a) to (d) which it can be seen this scheme wld comply with.

7) This application is needed because the proposal does not comply with the MCS and is therefore not ‘permitted development’

8) Specifically, the proposal would operate at 7.5 dB(A) above the prescribed MCS (Permitted Development) level of 42dbA

9) The SMDC EHO advice is that this is “a very high level of noise to impact the outside of a neighbour’s property on a regular basis and throughout the night”.

10) The EHO also advises that the proposed ASHP noise would cause sound levels inside the nearest bedroom of the neighbouring property to be approx. 34 db(A) and this is 4 dB(A) above the prescribed maximum night time bedroom levels of 30dB(A) as set out in BS8233:2014.

11) The applicant says that a central heating flue would cease [check is the oil htg system to be removed?] to operate and this is more noisy and would operate for longer and is closer to the neighbour.

12) The applicant has identified ASHPs nearby on adj dwellings with he says 48.4db(A) noise and not causing complaint. These were granted planning permission under reference SMD/2013/0913 on 20th September 2013. It’s not recorded what specifications and prescribed standards were being used at that date and how the proposal was assessed at the time.

In conclusion the SMDC EHO advises that:

“The 7db over the MCS level is significant. This is not a marginal level. If there is any option to relax these levels in the legislation or MCS then that should be in the submission. A noise assessment if undertaken may show background levels to be higher than that set out in the MCS but given the relative rural/residential nature of this area then I’m inclined to say background sound levels will be low.”

I have asked EHO what might be done to change the assessment outcome. His response leads me to think it is worth asking you if there could be scope to consider relocating unit? Or (ii) if some form of sound barrier could be erected which may mean the unit would comply with PD -or come closer to compliance.

Ultimately this is a planning decision and the EHO is our specialist source of advice but to take a different stance wld need good reason – an example wld be if you were at a house set apart from others where it wld be understandable that the standards wld not be so critical to adhere to in full.

Currently with only 3 oil filled radiators on downstairs (1500W each and not on Full bore) the house is quite comfortable - I think down to a new extension with good insulation that encapsulates the back of the house upto the bottom of the first floor windows.

Would be really happy if people can continue to contribute, MB

Posted by: @morgan

Planning portal.

https://www.planningportal.co.uk/info/200130/common_projects/27/heat_pumps/2

I thought that as long as an ASHP passed the criteria for permitted development (PD) that was it; nobody, including council planning could object.  The link above includes some basic criteria, plus the general one that the installation should comply with the MCS planning standards.  There is a summary of these here:

https://www.shetland.gov.uk/downloads/file/3123/ashp-mcs-020-noise-impact-assessment

and the full document here:

https://mcscertified.com/wp-content/uploads/2021/10/MCS-020.pdf

If PD doesn't apply then I assume it would have to get past the council planners.  They may have their own standards but if they don't they should be pointed at the MCS ones.  I can't see any mention of hours of operation in the above, just noise levels.

I get the impression people object to ASHP noise just because they can.  Ours is more than drowned out by the freezer, bathroom fans and a lot of other background noise.  Our neighbour's oil boiler vent is a lot noisier than our ASHP. 

I can see that noise may be a problem in certain, limited circumstances but these are covered by the calculation method in the MCS guidelines.