Moonshine

Decibels are a logarithmic value, reduction of half the pressure is a 3 dB reduction (= 10 x log10(1/2))

You are incorrect in the 42 dB applying to the host dwelling and this is actually applied at the nearest house, so in effect you don't need to worry about the noise level at your house if you don't need to. Is the ASHP going in as PD or under your planning application? if under your planning application then you won't need a MCS020 certified installation which will save you money. Your local authority may ask for a noise assessment to be done for planning, but this is easy and when i did mine just followed the methodology set out in MCS020, and submitted that (there is a MCS020 noise tab in the following spreadsheet) https://mcscertified.com/wp-content/uploads/2019/09/MCS-Heat-Pump-Calculator.xlsm For option B or the variant of it, it seems that the neighboring properties are over 20m away with a fence acting as a barrier, so a unit with a sound power of 57 dBA will be fine for planning. The issue of noise is really reducing the impact on your own home and garden and isn't a concern for the planners. your red dot does seem the most logical place to put the unit on the facade, but will have more of an impact on the garden than the location of the green dot, though the green dot is just outside the main bedroom. is the build masonry or timber frame? The acoustic enclosures do work to a degree, but i have not found one that reduces the noise by a level as claimed, and i haven't found one that looks 'nice'.

It seems unwarranted in this case and adds to the cost, I don't know the sums for the heat looses and it would be good.if someone can do it. To me the best part is no part at all.

The sound power data here is the most useful information, and is 57 dB(A). How loud it is dependant on the surrounding reflective surfaces. What is the green block in your layout, the extension? A. i think this is asking for trouble with your neighbours, and getting soundproofing to work with airflow requirements is tricky / expensive so i wouldn't go down this route. You would be looking for something like this https://acousticenclosuresltd.co.uk/air-conditioning-gallery/ and would run to £1k+ B. probably the best (or variation). C. I wouldn't have it too far from the house as you would get heat losses in the pipes even with insulated pipework D. Don't put it on the roof, weight / mounting issues and noise source is elevated so can travel further. The noise from the ASHP is all the fan noise and is very directional in the way the fan points. If it was me i would have it against the house to the southern boundary, facing to the east. there would be a fence to the neighbours to the south to attenuate the noise that way. On your site i would put a low wall / fence to the northern side of the ASHP to attenuate noise from it to the north into your garden.

i can probably assist ? Do you know the unit you want to use, and have you images of where it is going or plans, also where are you trying to reduce the noise?

I think that you are missing something quite fundamental, while those people are having showers the ASHP is working to top up the hot water in the cylinder, also the water in the tank is at 55 degrees, showers are at about 40 degrees, so its too simplistic to say it takes the full 100l from the cylinder. I have been asking the same type of questions of the supplier of the ASHP system i am looking to get, based on a 9Kw ASHP and 250l tank, it can heat the water in the tank from cold to 55 degrees in 30-40 minutes (depending on outside temp). However that scenario won't happen as in normal operation the water would not drop down below 20 degrees due to the insulated tank, and it would get up to 55 degrees in 10-15 minutes. This is how i understand it to work, in a morning scenario. ASHP switches on to heat the house as a priority. When the house is up to temperature and hot water in the buffer tank, the ASHP heats the main tank (already warm from day before, say 20 degrees). When the house and tanks are up to temperature, the ASHP only operates to top up the tanks when needed. Demand comes from showers and household activities Shower 1 - takes 70l of 55 degree hot water from the tank to be mixed with 30l of cold to take your big 100l shower over 10mins. The ASHP tops up the tank to replenish the heat lost, it may not make up all the heat but there will be some gaps in showers being on repeat

Hopefully that is the case as retrospectively doing it would be a pain in the bum

My understanding with trench fill is you typically bring it to 150mm below ground level. Though one thing you may want to consider is because you are pouring two layers of foundation, you may need to structurally link them with rebar. like this in vertical https://nhbc-standards.co.uk/4-foundations/4-3-strip-and-trench-fill-foundations/4-3-13-construction-joints/ I have just done this, where the footings are about to be poured over a mass foundation as below (i embedded the rebar in just after the pour) in your case if you want to do this, you are going to have to drill into the existing concrete and affix rebar studs in it

BCO has been today, and is happy (the first thing he said when he came to site was 'that looks solid'). Conctrete booked for Thursday, woohoo.

Well I couldn't get a concrete (pun intended) answer from the S.E and time is ticking on, so decided to dig 500mm deep trenches which are at least 1m below final ground level. Also deep enough not to sucharge retaining walls as per SE spec. All by hand (there was suppose to be a digger on site to do it but that is another story)!! It took all yesterday with help from my brother in law in the morning. Off camera to bottom left is a 8m run of trench I am going to get the bco on site mon/tues and hopefully poured Thurs if its o.k (praying for little rain), may just fill the whole depth.

Interesting study, and I'll have a read through (only skimmed it for now), especially how the measurements correlate to the siting of the unit. One point to note is 4 out of the nine were as per the manufacturers published data. A flaw in the assessment of tonality is they have measured how tonal it is at one metre from the unit and assumed it will have the same tonality at a receptor some distance away. This does not happen in real life as the tonal elements reduce in level at a distance, and are more easily masked by the ambient noise level at the receptor. A key key point of how you assess acoustic characteristics of sound is what those charateriestics are at the receptor not the source (see BS4142:2014-A.1:2019). So that 45m distance stated is flawed.

Can you direct me where to read up on the other side, genuinely interested.

where?

So it looks like this went back on the market https://www.zoopla.co.uk/for-sale/details/55489959/?search_identifier=3c744a657f2d03bc259cbecb58610178 It went to auction yesterday, sold for £170k https://www.cliveemson.co.uk/properties/227/85/ I wonder what happened to the march buyer.... or when the new buyer finds out its a bit of a lemon.

Down form near Plymouth, I nearly choked on my hob nob when I worked out it was £17 a ton delivered. A pile of 20T of stone is a site to see, especially when you know it has to be shifted to behind a retaining wall.

i got 20T of 20mm clean quarried granite for £340 + VAT delivered. I got about 37T of it backfilling my retaining walls on Monday,

That is a big ASHP and price tag, is it a big house? I have just had a quote back for 9kw R32 Monobloc (£2.1k) and 250 litre pre plumbed cylinder and 50 litre buffer for £4.5k supplied, and £1.5k for the under floor heating parts, at trade prices (No RHI scheme required or MCS20) Beats the £12k quote i got from another supplier just for supply. Now i need to find someone to install it! (any ideas how to track someone down?)

Is a concrete oversite needed under block and beam floor? i see some designs specify a concrete oversite, and other that the vegetation needs to be striped and weed killer down. my build proposes the latter, what is typical?

RML (https://rmuk.co.uk/) in with an order for my roof and floor joists

Go direct to Sales@armadillonv.com i was quoted in October last year Armadillo ARMATHERMTM 500-160 Thermal Breaks 2000mm x 100mm x 50mm Blanks TB1 £20 per unit Armadillo ARMATHERMTM 500-250 Thermal Breaks 2000mm x 100mm x 50mm Blanks TB2 £20 per unit

Have you also looked at armtherm? https://www.armatherm.co.uk/

I feel he is correct that heat pumps aren't suited to existing housing stock due to poor insulation and the grant scheme is inflating prices. I don't know how common it is to fit a heap pump to a existing house but in those cases I think he is right. He mentionedthat for them to work that house needs to well insulated and draft proof which even all new houses aren't. I don't agree that gas prices are going to be raised to discourage boilers, and can't image there would be enough to warrant mis-sold claims

I wonder if these would work, with the hole for the.plug slightly above the mortar line, ummm. https://www.screwfix.com/p/sabrefix-frame-ties-10-pack/24936 Not the intended use, and not sure about galvanised steel rather than stainless, though it's not on a external wall and should not be getting wet.

Thanks, those screwfix ones are too long and not stainless steel. I have just looked on line at my local MKM and it doesn't look like they stock them. Worth a call in the morning though.

The waterproofers have been today and left a load of plugs for the brickies (when they know the block levels) to drill through the waterproof layer and fit a plug, as below. However they haven't left the screw ties that go into them (which i thought that they would do) Where the heck can i get a suitable wall screw tie for a 120mm cavity at short notice, anyone help? this seems like a suitable product (though expensive) but i doubt that they are stocked at a LBM https://bsfixings.uk/bluebird-cavity-ties/