Tony K

Sorry, what do you mean by BB? At risk of stating the obvious, the bricklayers need the edges clear to build the walls so I'm limited to storing blocks in the centre of the slab if at all.

Hi all. My blocks are arriving soon, and space is tight on my plot. I'm looking at storing the blocks on the slab. SE has said this... The concrete slab has been designed for a total of 250 kg/m2 loads in addition of the selfweight and slab make up. Consequently, when storing brick pallets you have to ensure that the height of brick on the pallet does not exceed this load allowance. Typically a brick pallet weight between 1.5 to 1.7 t (depending on the brick density). So depending on the size of the pallet one pallet will be borderline to exceed the load allowance. I would advise that you spread the load by removing some bricks off the pallet. A dense block is about 18kg, and a pallet holds 72 blocks, so that's about 1300kg (as the SE states). A pallet is just shy of 1m2. What I don't understand is why, if the slab can only take a quarter of a tonne per m2, the engineer has described one pallet as 'borderline to exceed the load allowance'. Surely one pallet will be more than five times the maximum weight allowance? The SE is away on holiday at the moment, so if anyone can see what I'm going wrong in my reading of his comments I'd be grateful!

My brick and block walls will be going up soon, and I am still debating which front door to buy. I appreciate that doors don't really come in standard sizes as such, but ppresuming use of a normal single front door approx 2032 x 813 is it possible nevertheless to leave a 'standard' size opening in the wall and make my mind up about the door later, or better to choose a specific door and frame now? If it is the former, what size is the 'standard' opening for this purpose please? If it is the latter, is there any need to make the opening slightly larger than the given dimensions of the frame? Thanks

Cheers @ProDave

Brilliant. Thanks @ProDave Is that for the 12 or the 8 kW pump?

Thanks @ProDave https://www.nibe.eu/en-gb/products/heat-pumps/air-source-heat-pumps/NIBE-F2040-_-228

Thanks @ProDave Is there a place I can see the loading requirements within the technical spec for an ASHP? I looked but couldn't find one for the nibe pumps.

Am I missing something here? As part of getting a power connection to my SB I've been asked by UK Power Networks to confirm the loading requirements for my ASHP so they can establish whether I will need a single or triple phase connection. I've had two designs for the heating system, one proposed a 12kw machine, the other an 8kw. Am I correct to think that the kW number is the loading requirement? Also, does anyone know v the point at which triple phase becomes required, and whether it is significantly more expensive than single? Cheers

Useful advice as ever on here, thanks. Regarding noise alone, my conclusion is to install the ASHP, see how it goes especially when it is configured and programmed to best effect, and then go for a cover if needs be. I've recently looked again at the advice I received from the heating engineer who quoted for a system that includes the nibe pump, UFH and water tanks. I'm reminded that he raised the idea that my water tanks could be housed in an external timber lean-to if I preferred, so as to free up space in the utility room, so long as the lean to was properly insulated. As part of this scheme I would place my ASHP on the far side of my (small) garden, and run a 160mm round diameter connector with 2 x 32mm poly pipes installed inside it, all 1.2 metres below ground level. In the end I felt I could fit the tanks in my utility room (just), so I didn't pursue the idea. Looking at it now it also occurs to me that placing the ASHP on the far side of the garden means facing it towards my property, which appears a bad idea if, as I think I now understand, they operate a bit like speakers with most sound projecting from the front.

Mechanical. Whirring. Distinctive.

Volume or type? The specs tell me they emit something around 50bd, and as part of my research I've been to see (or more to the point, listen to) ASHP systems installed by one of the firms quoting for my business. I would describe the sound as noticeable.

Thanks for this @Dan F That's precisely what I will do @joe90 but before I take the plunge I'd like to understand whether I can realistically make any meaningful change to noise level if the worst comes to the worst and I find the noise uncomfortable once the ASHP is up and running.

The question though @Moonshine and @joth is: Does it work? I am keen on using an ASHP, and after considering some of the more concerned comments on here about efficiency, extent of slab insulation etc remain content to proceed but am concerned that noise might be a deal breaker. If I can be relatively confident that, should the ASHP sound prove more invasive than anticipated I do at least have the option to construct an acoustic enclosure which will be effective, that will be enough for me.

Something of possible interest to those concerned with noise from ASHPs: I received this from a local authority Environmental Health officer that I know: I don't really know much about these pumps and how they work. It is always difficult to be confident about these matters without knowing background noise levels and exact distances to nearest windows, etc but a robustly constructed timber enclosure with no gaps and good density of timber with something like 50mm rock wool insulation to absorb reflections should give a good 10dBA reduction, although attention may be needed for ventilation. It's always a compromise. Night time noise levels of 30dBA at residential windows is fine for the vast majority of neighbours, even perhaps 35dBA. For distance attenuation assume 6dB for every doubling of distance. So, if the plant is 45dB at 1m, it will be 39 at 2m, 33dB at 4m. This will be the maximum attenuation - likely to be slightly less due to reflections in the built environment.

Split units meaning that part of the ASHP lives indoors? My thinking was to use one of their sound enclosures (or one like it) over a NIBE external ASHP, if the enclosure serves purpose, but as per my earlier post I don't really understand the extent of the claimed noise reduction made in the video.

There's only one thing I don't understand about what you just said @Moonshine, and thats all of it! ? If I buy one will it halve the noise levels?

Regarding noise reduction, this is interesting, though I am not sure I understand the claim to have reduced the noise from an ASHP 'by half', when the graph shows a 3db reduction?

I haven't read the MCS standards, but I presume that is where you are getting the 10m distance from? Many will have included the ASHP in their planning application and so whilst they will need to ensure compliance with any relevant planning conditions, will not need to worry about complying with the terms of the General Permitted Development Order (the Act which brings Permitted Development rights into law, and sets out the detailed regulations). Those of us relying on PD rights may already appreciate that the GPDO requires that 'the air source heat pump complies with the MCS Planning Standards or equivalent standards' along with a series of other, clearly set out constraints and conditions. It's not unheard of for the GPDO to refer to other Acts (the definition of a 'caravan' in the GPDO is as per the Caravan Sites and Control of Development Act 1960 for instance), but reliance on a standards document 'or equivalent' is unusual. I presume this part of the GPDO accommodates the idea that ASHP technological development may be fast moving, as will knowledge around the subject and best practise therefore. Therein lies an issue I would advise awareness of. The GPDO does not currently require you to register the presence of your PD ASHP with the planning dept either in advance or after installation, but anyone wishing for the peace of mind that comes with formal confirmation, in advance of any works onsite, that their Council agrees their ASHP is covered by PD can apply for a certificate of lawfulness. However - a certificate of lawfulness can only confirm that the subject operation (installation of a ASHP in this case) would have been lawful on the day you applied for the certificate, not the day the certificate was issued and certainly not on the day you get around to installing the ASHP. A certificate of lawfulness has an ever-depreciating value in that way. If the regs, and in this case the guidance, moves on between the date of your application and the date you install it, you need to accord with the regs and guidance as they exist on the latter, even if that means doing things differently than you said you would when you applied for the certificate. How much all this matters depends entirely on how quickly and significantly the MCS Planning Standards or equivalent standards move on, and how much difference any change in them makes to your proposal, but given most of us planned for an ASHP a long time before we ever installed it, it is worth looking at the MCS standards once again before installation.

Thanks @Moonshine. The GPDO regs (Class G Permitted Development) don't specify which windows noise must be measured from (or refer to noise at all), they just rely on the MSC standards. I have read a guide to those standards which seemed not to discriminate between host windows and neighbouring ones, but haven't read the actual standards themselves, so I'll take your advice, thanks. I don't think it really makes a lot of difference in this instance - I will be looking to reduce noise as far as I can for my own sake and for the neighbours. The nearest neighbours windows are some 7 metres away from position B, but my new house is located between those windows and position B, so I would be surprised if 42db were to be recorded. The ASHP was not explicitly shown on my planning application, so I'll be using GPDO Class G rights. I note the GPDO does not require prior notification, or submission of evidence that the MSC standards are met, only that they are. This gives me a little leeway in practice - I will install the pump in position B, see what it sounds like when it is up and running, and if it drives me mad then I'll look at an acoustic enclosure for it, thereby following advice from @IanR. I can't imagine that the heavy industrial acoustic enclosures on the link you provided have any great magic to them - surely I can achieve something worthwhile by attaching sound insulation to the inside of a timber lean-to / log store, and placing that around the ASHP? This would affect noise emissions and also provide some thermal insulation around the pump, which I understood to have functional benefits. My SB has a masonry frame. @PeterW suggested that there were benefits to locating the ASHP perpendicular to the house wall, but has not yet explained his thinking on that front. Would I be right to presume that a perpendicular position would reduce the extent of sound echo off of the house wall? I will also have a quite densely green garden once it matures, including some of the plants on the list @joe90 provided!

Thanks @IanR that's very useful.

@PeterW what is achieved through perpendicular positioning please, and are you suggesting the ASHP be located without noise reduction housing?

Thanks @Moonshine, much appreciated. Ignore the green and grey blocks, it is one L shaped bungalow with a flat roof. If I opt for position B as you suggest I have a couple of options. The red dot is the obvious place for it, the green is where you suggest: The PD regs for ASHPs stipulate that noise levels must stay at or below 42 decibels (dB) from a metre distance away from any habitable room, including (I presume) the host dwelling. The spec suggests a sound power level of 57db. I am not sure how I can square that spec with the PD regs therefore, unless of course the sound is directed somehow so that despite being near my windows, the actual sound from the ASHP is at or below 42db. Is that how it works in your opinion? Your suggestion of a screening low wall suggests that I can manipulate the direction of sound from the ASHP. Is that so do you think? I am interested in the acoustic enclosures you linked to, thanks. Do you know how they work at all? I wonder if I can make a less industrial looking enclosure to similar effect. I had made these notes some time ago, and would be interested in your views, particularly in whether in fact I would do better to open the doors so the noise can be directed away:

Thanks. At the moment I'm looking at a NIBE 2040-12kw air source heat pump. The spec is: Layout wise, I'm looking at a few options: A. In the alcove. Its within 1m of the boundary but would live inside the timber structure that will occupy that inset section, and provide storage for bikes etc. It could therefore be soundproofed. It would require planning permission there of course. B. On the inside facing wall of the bungalow. C. In the garden, somewhere at least 1m from the boundary. D. On the flat roof. Sounds counter-intuitive, but I wonder if in fact noise would be less amplified there.

I appreciate that @joe90, I really do, but I've not got the time or inclination (and probably not the skill set) to design it myself. I've done a lot of the heavy lifting on this SB, and will be doing plenty more, but getting a system designed is on the 'farm off to others' list and isn't coming off! What I'd really appreciate is any advice from anyone who has tried to contain, reduce, or direct the noise from an ASHP. I'm quite tightly packed in on my site, and the SB itself will be an L shaped one around a courtyard, so my instinct is that the citing of the ASHP is a crucial consideration, as s any noise limiting set up I can arrange.

If I could be a diva and make this all about me for a moment please... ? I started this thread as I was concerned about noise. Replies (for which thanks) have covered : 1. Whether an ASHP is right for my SB or not (at least one learned poster has suggested it won't work). 2, Whether they are any good at all. 3. How noisy they are. 1. I think an ASHP will work for me. I have full plans approval which includes a SAP calc based on 90mm PIR insulation between my RC slab and my 65mm UFH/screed, but I can alter that to 100mm insulation and 50mm liquid screed, plus I have ceramic tiles (a very good conductor), I will have significant south facing glazing, allowing heat to soak in the slab and walls in summer and release in winter (overheating to be avoided with a canopy), and I have good overall insulation standards, which matters as much as under floor insulation as far as I can tell. I will place my insulation inside the building, not under the slab. I appreciate the cold bridging effect this can create, but most UFH suppliers advise that my arrangement leads to more efficient performance. 2. The ranting video from SkillBuilder actually captures some good points (the 'rant' element is for humorous purposes largely) and is quite clear that whilst ASHP tech isn't always a great fit, it very often is perfectly good in well-insulated new builds with UFH, and especially where the overall system is designed holistically by an engineer. I do not have, nor do I intend to develop, the interest in and knowledge of the subject that some on here clearly have, and so for me the question is who do I engage to produce a holistically designed scheme, and can I implement bits of it myself to save a few quid. I'd guess the UFH is one, and then ask the installer to give it the once-over. What I've learned from some of the replies on here is that there are a number of small elements that can matter greatly, and which I will pay an installer to do. 3. The only thing I remain concerned about is noise. As some have said, the quietest ones still run at 45-50db, and the fact that the permitted development regs themselves include maximum noise levels speaks volumes. I have gone to new builds to listen to ASHPs and consider the noise noticeable. I will need to better understand this aspect. Does intermittent use vs steady constant use help? Is it as simple as to say that they are more active (and noisy) in winter when windows are closed, and generally sit silent in the heat of summer when windows are open? Can I fit any kind of noise-reducing housing around the pump?