Tony K

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?

I quite like the skill builder YouTube channel, and I'd recommend it to anyone on here wanting to see building work of different types done well. I haven't watched the most recent Skill Builder rant about ASHPs (and it is a rant, partly tounge in cheek by the presenter), but I did watch the last, fairly recent one on the topic in which the presenter is perfectly clear that ASHP work fine in a modern, well insulated house - it's the attempted use of them in the wider, older housing stock he takes issue with.

It's approved by building regs already (full plans approved). Why would that be insufficient for UFH? It's an L shape, 5m wide if that makes a difference?

You might regret that act of kindness @joe90!

The slices of the cake go: Ceramic tiles. Screed with UFH inside. 65mm. PIR insulation 90mm RC slab.

@PeterW and @SteamyTea thanks for the detailed advice. My SB will be well insulated, have UFH and good (though not passive standard) air tightness. My research prior to commencement led me to conclude that an ASHP would be a good fit, and I though I remain of that view I can see from your replies that there is a level of detail beyond my understanding which may be critical to the success of the system. Would you expect most good suppliers / installers to apply the level of attention to detail you describe, or is there merit in appointing someone to oversee the optimum configuration of the system? @Dave Jones you plainly feel differently to many others on this subject, but I've no reason to think you aren't saying it as you see it and trying to give me best advice, so thanks.

You sound like you've had slightly more negative experiences?

That's very useful, thanks.

Have to say I don't know. My own SB is small (100m2 single storey). Will that make a difference do you think?

I spoke to an environmental health officer I know about ASHPs. He said they can and do cause noise nuisance complaints. Before I opted to use a heat pump I went along and listened to someone's, and it wasn't comparable to a fridge! The best argument I heard was that they aren't used in hot weather when neighbours windows are open, which made sense. I think I'll position it in the corner of the garden if possible, and then look into noise reduction if needed.

How far away is yours from the house then?

I had considered making one using the stuff from recording studios. No idea if that would work mind you. How quiet is yours then? I thought they were typically 45-55 dB?

Anyone tried these? Any good? Expensive? No matter where I put my ASHP it'll be audible to someone, and I'm interested in designing in a sound reducing set up from the outset if it's worth it. I'd be interested in anyone's experience of this technology. Thanks

Afternoon all. My SB uses piles and a floating slab, though which foul pipes will take waste water away to the sewer from two small bathrooms: The bathrooms are 1600mm x 1600mm internally. Above the slab will be 90mm insulation and then 65mm screed (in which will live the UFH), plus the finish on top. I am now toying with the best way to arrange the waste pipes, including the best place to put the FWP. The walls are timber studwork, so I could possibly run a pipe from the sink through the wall to the bath and then under the bath, into the wall again, and then connect it to the w/c. Another option some have suggested is that the pipes from sink and bath are run through the screed and insulation, sitting on top of the slab in effect, but my concern is the effect of this approach on the thermal envelope and the UFH. Either way, it seems logical that the FWP should pass through the slab where it can be connected directly to the w/c. I am also giving some thought to installing a channel grate in the floor between the sink and w/c. I am not creating a wetroom, but nobody in my family seems able to have a shower without soaking the floor, so I could factor that in now. If anyone has any pearls of wisdom regarding the best plumbing layout, and the pros and cons of a channel grate I'd be grateful! Cheers

It should be as simple as showing them your soakaway design shouldn't it?

Nope

@JD44027 It was about 40k for the piles, that's 39 piles at about 6-7 metres deep. Then add the cost of the slab. My costings are a bit unique due to my odd site. There's another thread nearby where costs are discussed, so take a look. Good luck!

I'm on clay with lots of trees and went for steel screw piles, though partly that was due to other logistical factors too. Not cheap, you'll need an engineer to design it and there are only so many firms who do that work. The trees near me are much closer than yours though. Presuming the trees are to be retained, get a soil survey done and an arb survey of the roots, then you can get an engineer to tell you your options regarding foundations. Also consider drainage at the earliest stage. The soil test will tell you if a soakaway is viable or not, and you'll need to know that ASAP.

It was a pond in winter! I've nowhere to gravity drain it off too but it doesn't matter as I've got the sewer run next to the site and a small pump is more than sufficient. It's just the base of the area. It dries hard enough in some places, but stays mushy in others, suggesting rising moisture. In fact when we literally hover one or two areas dry in the morning they have tiny puddles again by the end of even the hottest day.

I doubt I could have a French drain around the house. It's built into the corners of an urban plot, so I've no space outside for it, plus the design has the slab backfilled around the edges in what I think they call a fit and forget arrangement. I will set up a temporary moat drain inside the footprint and try to save the cost of extra hardcore etc.

Thanks all. I'll try leveling the surface with the digger and creating a moat around its edges, just inside the excavation walls. I will pump any water away from that moat over the weekend and see if the main surface dries out properly. Then I'll consider extra material and possibly a matting underneath.

Thanks @Temp We had considered this option. Not cheap, but might be worth it. A geotextile firm I spoke to this morning didn't have any obvious solution they could offer.