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Why not A2AHP?

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  • @2nd_time_buyer
    I will have to disagree on the requirement of planning permission. Unfortunately, any system which can cool requires one.  The current systems are very very quiet and the legislation is lagging behind technology, but when they are installed and like with any machinery the noise will increase over time. This will be a big problem in built up areas where the ambient noise is low. 

    The below is from the Environmental Planning Officer in relation to my planning application. The distance from the two units to the nearest dwelling/house are 8m and 11m respectively and I live right next to a busy road.  

      

    Thanks. I stand corrected on the planning permission. We tend to get involved further down the line and I am embarrassingly ignorant in that respect.

    In most situations the noise assessment, if required, should not be that involved. You could probably do it yourself.

    In terms of noise nuisance the government guidance is that it should not be more than 10dB above background noise. With a minimum cap of 34dBA (24dBA + 10dB):

    https://www.gov.uk/guidance/noise-nuisances-how-councils-deal-with-complaints

    Measurements are typically in accordance with British Standard BS 4142 for the measurement of industrial noise in a domestic dwelling.

    If I look at the specifications of the 3.5kw Panasonic unit I installed, the outdoor unit has a sound pressure level of 47 dBA*.

    https://www.aircon.panasonic.eu/GB_en/product/etherea-inverter-silver-r32/

    That 47 dBA is measured at 1m. Assuming hemispherical spreading then noise decreases by 6dB per doubling of distance. Therefore at 4m the noise will be down to 35dBA (two doublings of distances). 

    So even with a background noise of 24 dBA which is very low, you would only need to be a little over 4m for there unlikely to be an issue in an open field site with no barriers (e.g. fences). In most suburban and urban settings the background noise will be higher than the minimum in the government guidance of 24dBA e.g. with no traffic noise in my garden I have just measured a minimum of 28dBA at 6am in the morning.

    You can download a free sound level meter app for your phone to sense check the background noise levels where you live. But I wouldn't quote those levels in the assessment as they wouldn't be calibrated. But if you can show it shouldn't be an issue with the 34dBA, then that should be sufficient.

    *It is important you look at the sound pressure level not the sound power level and also at what distance it is measured.
  • ispookie666
    ispookie666 Posts: 1,194 Forumite
    Part of the Furniture 1,000 Posts Name Dropper Combo Breaker
    It is baffling why the manufacturer of outdoor condensing unit (noise generating) will not provide a technical sheet with details of how noise falls off from their units upto a distance of 10m.  This will save a lot of problems for both the consumers and councils/planning.  

    “Don't raise your voice, improve your argument." - Desmond Tutu

    System 1 - 14 x 250W SunModule SW + Enphase ME215 microinverters (July 2015)
    System 2 - 9.2 KWp + Enphase IQ7+ and IQ8AC (Feb 22 & Sep 24) + Givenergy AC Coupled inverter + 2 * 8.2KWh Battery (May 2022) + Mitsubishi 7.1 KW and 2* Daikin 2.5 KW A2A Heat Pump
  • It is baffling why the manufacturer of outdoor condensing unit (noise generating) will not provide a technical sheet with details of how noise falls off from their units upto a distance of 10m.  This will save a lot of problems for both the consumers and councils/planning.  

    The reason is that the attenuation depends on the  environment. As I said above if you take the sound pressure level at 1m and then assume 6dB reduction per doubling of distance then that would get past most planning scrutiny.
  • gefnew
    gefnew Posts: 928 Forumite
    Part of the Furniture 500 Posts Name Dropper
    This may help with some of the explanation. 

    How Sound Reduces With Distance From a Point Source
    The area of a surface around a point sound source increases with the square of the distance from the source. This means that the same sound energy from the source is distributed over a larger area and the energy intensity reduces with the square of the distance from the source (Inverse Square Law).

    For every doubling of distance, the sound level reduces by 6 decibels (dB), (e.g. moving from 10 to 20 metres away from a sound source). But the next 6dB reduction means moving from 20 to 40 metres, then from 40 to 80 metres for a further 6dB reduction.

    Hope it helps someone.
  • michaels
    michaels Posts: 29,084 Forumite
    Part of the Furniture 10,000 Posts Photogenic Name Dropper
    gefnew said:
    This may help with some of the explanation. 

    How Sound Reduces With Distance From a Point Source
    The area of a surface around a point sound source increases with the square of the distance from the source. This means that the same sound energy from the source is distributed over a larger area and the energy intensity reduces with the square of the distance from the source (Inverse Square Law).

    For every doubling of distance, the sound level reduces by 6 decibels (dB), (e.g. moving from 10 to 20 metres away from a sound source). But the next 6dB reduction means moving from 20 to 40 metres, then from 40 to 80 metres for a further 6dB reduction.

    Hope it helps someone.
    Inverse square interacting with a logarithmic scale - loads of maths fun :)
    I think....
  • michaels
    michaels Posts: 29,084 Forumite
    Part of the Furniture 10,000 Posts Photogenic Name Dropper
    On a similar topic it annoyed me they did not support CHP gas boilers on the RHI and FIT schemes.
    I think....
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