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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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    • CommentAuthornbishara
    • CommentTimeJun 28th 2019
     
    I've been planning a well insulated extension and retrofit (high airtightness, better insulation, MHRV, PH certified architect) to my small, solid walled semi for....far too long. We were on the cusp of actually building when I realised that an extra metre on the gable end would cost little in terms of the overall build cost and make a big difference, so I'm in the process of reapplying for planning for the extra metre *sigh*

    My dilemma is that my builder (who has the patience of a saint) suggested cracking on with the EWI to the existing frontage in the meantime - which I'd really like to do. However, someone who has a lot of expertise in the field previously recommended that I got the insulated extension built and had the EPC done before the EWI for the benefit of the RHI.

    I think I get the implications of this, but frankly, as the purveyors of heat pumps seem to have jacked up the prices of them to reflect the RHI, I'm keen to get as much back of the 17k that I was quoted for an air source heat pump for my fairly small and small heat load (c8kw) property.

    If I won't get away with it, or it will bugger up my heat load cals for the heat pump, I'll crack on with the EWI - but if I might get more of the overpriced heat pump paid for...I'll take the advice I was given with regard to the EPC.

    I should note that, eco ethics aside, I'm on bottled gas or I wouldn't be considering a heat pump as a good idea. I'm also acutely aware that air source can be useless...another reason why I'd rather pay as little as I can for one.

    I think the estimates for our current heat load are around 8kw and we have a 5kw clearview stove. We've survived three winters with just the stove and no ewi, so I'd be tempted not to bother with central heating at all...but if I ever sell I ought to have it and who knows what winters will be like in the future.

    any advice (inc good heat pump suppliers) very much appreciated,

    Ishara
    • CommentAuthorjfb
    • CommentTimeJun 28th 2019
     
    17k is a huge amount for an ASHP install. Many people don't bother with the RHI as monobloc ASHPs can be relatively straight forward to install.

    Are you planning on UFH in the extension and what is the plan for the existing house in terms of radiators? Low temperature heat is better for the ASHP efficiency so you might need large rads in the existing house and pipes spaced close together in the extension if going for UFH.

    How are you heating your domestic hot water? Does the 8kw heat load include DHW?
    • CommentAuthorGreenPaddy
    • CommentTimeJun 28th 2019
     
    In total ignorance of your current design, 2 things jump out at me;

    - £17k is a ridiculous amount to pay for any heating system. How can you possibly ever get that to pay back, even if it ran for free.

    - you say your house is a "small semi" albeit with an extension. If your architect can't get the space heat load down to around 2kW when it's -1oC outside, then there's something we're missing.

    I've just designed a refurbed stone house with existing extension, plus a new extension, (total floor area approx 200m2) with space heating demand of 3kW at -1oC and 5.5kW at -15oC, and I'm not pushing the insulation levels to where I'd normally design (breathablity being the main concern).

    As an Irishman once said, when asked directions by some tourists, "Well, I wouldn't start from here".
    • CommentAuthorgyrogear
    • CommentTimeJun 28th 2019
     
    For 17 thousand pounds, I'd prefer to buy a trailer tent etc. and spend the next 20 cold seasons in Spain or somewhere...

    gg
  1.  
    Ishara, did I read your post right that 8kw is the existing heat load, and you are planning to add EWI to substantially reduce this?

    We paid a lot (but not nearly that much) for a bigger heat pump than yours, much of the cost was an accumulation of smaller jobs like replumbing the house, new fuse box, moving wall, etc to suit the heat pump. I am sure it would have been cheaper to do it non-MCS but we liked the MCS firm.

    We subsequently claimed RHI when it first came in. The RHI claim was based on the EPC that is in place at the time of the claim. They subsequently contacted us each year to ask us to declare there had been no modifications to the system or house that would trigger a re-evaluation of our claim, with warnings that we could be asked to repay the RHI or be done for fraud if we failed to disclose any changes.
    • CommentAuthorowlman
    • CommentTimeJun 28th 2019
     
    As others said £17k is far too much IMO.
    I've just installed my own air to air heat pump, complete with insulated metal spiral ductwork and all the associated dampers with high quality ceiling registers, interconnecting cables and insulated copper refrigerant pipework in trunking, and digital controls. The total materials bill inc VAT will not be more than £4.6 K and that's for a fairly complex system arguably with the ducting, more so than an air to water system.
    I'm still waiting for the f gas fitters bill for commissioning but I'm not expecting more than a few hundred. Based on that the labour content of your install costing, seems excessive does it include other stuff.

    I'm also interested in this sentence of yours, tania.

    "I'm also acutely aware that air source can be useless...another reason why I'd rather pay as little as I can for one."

    What makes you think that?
    The COP on my system, can be up to 5.5 on an A+++ R32 inverter. I can't claim RHI because it's air to air system but even so I think it will be very efficient, and I can use it for Summer cooling.
    •  
      CommentAuthordjh
    • CommentTimeJun 28th 2019
     
    Posted By: owlman"I'm also acutely aware that air source can be useless...another reason why I'd rather pay as little as I can for one."

    I'd also add that whilst the first part might be true in a few, hopefully getting rarer, cases I don't think the second part follows on. Look for a quality product and an installer that you trust.
    • CommentAuthorJeff B
    • CommentTimeJun 29th 2019
     
    <blockquote><cite>Posted By: jfb</cite>17k is a huge amount for an ASHP install. Many people don't bother with the RHI as monobloc ASHPs can be relatively straight forward to install.</blockquote>

    jfb - an interesting comment that. I am considering an ASHP when the RHI payments on my wood pellet boiler cease in about 2 years time but I am cognisant of the fact that having an MCS installation is going to cost a packet, a lot more than just the cost of the kit! Would the installation of an air to water system be a DIY job and would there be any warranty on the kit if I did do the work myself? My brother-in-law is a plumber so we could do it together but if he bought the kit then I should be ok warranty-wise.

    There is no possibility of UFH here so it would mean extra large rads which could incur considerable extra cost as well. The space heating demand is about 14,000 kWh per annum. DHW is provided by solar thermal in the summer months (with immersion heater top up on dull days) but by the boiler for the rest of the year.
    • CommentAuthorjfb
    • CommentTimeJun 30th 2019
     
    Well I am not an expert myself but I am considering a similar thing. I think some of the ashp combined with a pre plumbed cylinder are particularly easy to connect up. I'm not sure how well suited your situation would be for an ashp. 14kw is a very large heat load and lack of ugh/needing to buy new and large rads doesn't help. It could well end up being very expensive if you are not able to keep the heating temperature low. How well insulated/airtight is your house? Do you have 3 phase? don't think you could run an ashp that large on a single phase. Regarding warranty I am not sure but no harm in askin some suppliers.
  2.  
    Posted By: Jeff BWould the installation of an air to water system be a DIY job and would there be any warranty on the kit if I did do the work myself?

    Health warning - I don't have legal training - but I don't think that doing a DIY install should affect the warranty. You could well have a problem as the supplier might try to use the DIY install as a way to sneak out from under the claim but they would have to show that the installation caused the problem. IMO they can't just walk away from the problem just because you didn't pay a fortune to some company to install. Of course if the unit requires filling up with refrigerant gas as part of the install then different regs come in.

    From my own experience 24 years ago I bought a new car (in the UK) which had a failed gearbox after 3 years and 130k km. The problem was a known design fault and quite a lot of boxes had been changed. The time and km. were well outside the warranty period. The company asked for the service history and when I said private garage not main agent they tried to walk away but I claimed that the failure was nothing to do with who serviced the vehicle but was a design/manufacturing fault and started to quote the 'fit for purpose' regs. at which point the company rolled over and I got a new box delivered and installed for free. By the time the failure happened we were in Hungary which then was not yet in the EU.

    The EU regs and UKs consumer laws are much stronger now than 20 years ago so I would not expect the supplier to be able to get out of a claim just because it was a DIY install but they would have to show a causal event from an improper installation.
  3.  
    The 5 year warranty on our big-brand ashp was conditional on:

    1) had to be installed by a MCS firm who were trained/approved by the manufacturer
    2) had to have a very expensive annual service contract with a MCS firm ditto

    The ashp ran faultlessly for seven years then failed out of warranty. The labour rate for heat pump firms is a lot more expensive than for oil/gas boiler firms. By the time they'd spent a few visits tinkering with it, the cost was such that it was uneconomic to repair.

    On the plus side, they were able to fit some expensive spare parts (circuit boards, inverter etc), then remove/restock/refund them when that didn't fix the problems.

    Configuration of the system required plugging in a laptop and entering a load of codes that were downloaded from a manufacturer's website that is only accessible to approved firms.

    Next time I will look at DIY with a cheap Chinese ashp that can be disposable if I cannot fix it myself.
    • CommentAuthorgyrogear
    • CommentTimeJun 30th 2019
     
    Thanks for the very interesting insight, W in A.

    (I shall not be buying one !)

    :shamed:

    gg
    • CommentAuthorowlman
    • CommentTimeJun 30th 2019
     
    Posted By: jfbWell I am not an expert myself but I am considering a similar thing. I think some of the ashp combined with a pre plumbed cylinder are particularly easy to connect up. I'm not sure how well suited your situation would be for an ashp. 14kw is a very large heat load and lack of ugh/needing to buy new and large rads doesn't help. It could well end up being very expensive if you are not able to keep the heating temperature low. How well insulated/airtight is your house? Do you have 3 phase? don't think you could run an ashp that large on a single phase. Regarding warranty I am not sure but no harm in askin some suppliers.


    When I last looked I seem to remember the monobloc systems you refer to are usually available up to 16kW on single phase. Above that it's three phase. I believe that they were originally designed to dispense with F gas fitters, as everything is pre-charged and there are no refrigerant pipes between any outdoor and indoor units. However speaking to my F gas fitter many plumbers still call on his services to fit as it's all a bit too much like magic for them.
  4.  
    Posted By: WillInAberdeenThe 5 year warranty on our big-brand ashp was conditional on:

    1) had to be installed by a MCS firm who were trained/approved by the manufacturer
    2) had to have a very expensive annual service contract with a MCS firm ditto

    I am not sure that these conditions are enforceable in that if these conditions were not met the manufacturer would have to show that the failure was caused by not having e.g. the annual service - but you might need to go to (small claims?) court to enforce this.

    Posted By: WillInAberdeenConfiguration of the system required plugging in a laptop and entering a load of codes that were downloaded from a manufacturer's website that is only accessible to approved firms.

    Car manufacturers used to do this to force servicing by main agents only, now private garages can buy access to the info. but I an not sure if the info is manufacturer supplied or if garages buy a range of info. from a 3rd party supplier.
    • CommentAuthorgyrogear
    • CommentTimeJun 30th 2019 edited
     
    Posted By: Peter_in_HungaryI am not sure if the info is manufacturer supplied or if garages buy a range of info. from a 3rd party supplier.


    https://www.etas.com/en/products/solutions_onboard_offboard_diagnostics.php

    One has to distinguish between onboard diagnostics (OBD) and offboard.
    EOBD = "European Onboard Diagnostics"

    The former basically refer to pollution regimes and by EU law, have to be accessible by "any garage" using standard equipment.

    https://www.gendan.co.uk/article_5.html

    Offboard diagnostics are run from proprietary diagnostic tools, essentially PC-based, containing data that is proprietary to the car mfr (you are not allowed to decompile or rewrite his code etc.). These tools access and manage all parameters in all electronic control units on the vehicle, so the field is far vaster. They are generally made by specialized suppliers serving the industry, contracted by the vehicle mfr. So an outfit (garage...) wanting to troubleshoot a particular vehicle would have to buy a licence (and a tool) for that particular vehicle.

    The advantage in going to your own mark, is that after a prescribed time (say 45 minutes), if the mechanic has not located the fault, he can contact the online service platform. There, specialized (often multilingual) technicians working 24/7 can take control of the diag remotely and sort the problem over the net, using their own specialist knowledge and in-house databases compiled from incident sheets filed by each garage, distributor, service center etc. So a much wider troubleshooting approach, which obviously has to be paid for by somebody...

    gg
    •  
      CommentAuthordjh
    • CommentTimeJun 30th 2019
     
    Posted By: gyrogearyou are not allowed to decompile or rewrite his code etc

    That's an uneforceable term in European law, since you do have a right to decompile for the purposes of interoperability, I believe. And more generally, you can alter something you have bought to improve it, so far as I know, as long as nobody is harmed physically, mentally or financially.
    • CommentAuthorgyrogear
    • CommentTimeJun 30th 2019
     
    well, per the licence of PSA Diagbox, for example,
    "Lexia Diagbox pp2000 shall not be used with any other software purchased separately".

    presumably that excludes use of a decompiler...


    gg
  5.  
    I'm sure you are all correct in law... But if you check the websites of all of the big ashp manufacturers, their warranties are still conditional on the installer being someone trained/approved by them. They offer (free) training and approval for suitable firms.

    Same for many manufacturers of gas boilers

    Same for many manufacturers of EWI systems

    I think these markets are rather smaller than for new cars and the public have not demanded flexibility be enforced in the same way.

    You could always install DIY and just take the hit if there are any repairs in the first few years. Or be the first to test it in court (good luck with that).

    Obvs a heat pump is quite a serious electrical load outdoors, the wiring is not DIY.

    Technically an ashp only has Permitted Development rights if it can be shown to be MCS compliant.
    • CommentAuthorJeff B
    • CommentTimeJun 30th 2019
     
    <blockquote><cite>Posted By: Peter_in_Hungary</cite><blockquote><cite>Posted By: Jeff B</cite>Would the installation of an air to water system be a DIY job and would there be any warranty on the kit if I did do the work myself?</blockquote>
    Health warning - I don't have legal training - but I don't think that doing a DIY install should affect the warranty. You could well have a problem as the supplier might try to use the DIY install as a way to sneak out from under the claim but they would have to show that the installation caused the problem. IMO they can't just walk away from the problem just because you didn't pay a fortune to some company to install. Of course if the unit requires filling up with refrigerant gas as part of the install then different regs come in.

    From my own experience 24 years ago I bought a new car (in the UK) which had a failed gearbox after 3 years and 130k km. The problem was a known design fault and quite a lot of boxes had been changed. The time and km. were well outside the warranty period. The company asked for the service history and when I said private garage not main agent they tried to walk away but I claimed that the failure was nothing to do with who serviced the vehicle but was a design/manufacturing fault and started to quote the 'fit for purpose' regs. at which point the company rolled over and I got a new box delivered and installed for free. By the time the failure happened we were in Hungary which then was not yet in the EU.

    The EU regs and UKs consumer laws are much stronger now than 20 years ago so I would not expect the supplier to be able to get out of a claim just because it was a DIY install but they would have to show a causal event from an improper installation.</blockquote>

    Thanks. The Consumer Protection Act is great on paper but not quite so clever in practice. I have recently had a very similar experience with a car which has a semi-automatic gearbox. I did not know at the time of purchase but this model has a history of such problems. I took the car back virtually immediately (less than 24 hours of driving time) under the 30 day right-to-reject rules as it was not fit for purpose. Guess what? Surprise, surprise the car dealer refused to give us our money back claiming we must have damaged the gearbox! T

    o cut a very long story short, 3 months later our un-driveable car was repaired courtesy of Barclaycard (we paid for it using our VISA card) at a cost of £2100. So I would not like to rely on Consumer Protection laws to offer us any protection when it comes to a warranty on an ASHP which we had installed ourselves! Obviously we would pay for it using my VISA card but wouldn't like to rely on the credit card company coming to my rescue a second time!
    • CommentAuthorJeff B
    • CommentTimeJun 30th 2019
     
    W in A: thanks for your replies. Sounds as if the big manufacturers have got the market pretty well stitched up then. Maybe I should send my plumber brother-in-law on their free training course then?! Even then we might have a problem with Permitted Development from what you are saying!
    • CommentAuthorowlman
    • CommentTimeJul 1st 2019
     
    Posted By: djh
    Posted By: owlman"I'm also acutely aware that air source can be useless...another reason why I'd rather pay as little as I can for one."


    I'd also add that whilst the first part might be true in a few, hopefully getting rarer, cases I don't think the second part follows on. Look for a quality product and an installer that you trust.



    Those were not my thoughts Dave; I was simply Quoting the OP.
    I do agree however, that if you pay peanuts and install to a bad design, you're likely to get indifferent results.
    •  
      CommentAuthordjh
    • CommentTimeJul 1st 2019
     
    Posted By: gyrogearper the licence

    The licence is irrelevant if it contravenes the law.
    • CommentAuthorgyrogear
    • CommentTimeJul 1st 2019 edited
     
    OK, next time I see them, I'll let them know.

    As for, "altering something one has bought in order to improve it", this might sound somewhat pretentious in certain quarters, notwithstanding the likely impact on the warranty...

    No doubt this is what Lion Air and Ethiopian were up to then -- improving Boeing's stall warning system !

    gg
    • CommentAuthorgravelld
    • CommentTimeJul 1st 2019
     
    Even supposedly cheap(er) ASHP installs can get expensive quickly if you end up having to replace all your radiators and/or add new ones (this is a retrofit remember). Although probably not £17k expensive.
  6.  
    Looks like the OP might be getting burried under legal debates about ASHP?
    I didn't see a reply confirming how much space heating power is required for the property, which has to be the place to start, and also clarifying what the space heating output devices might be...ufh, rads.
    If it's PH arch designed, that info. will all be readily available.
    Guess I'm thinking that the OP's picked (and asking for advice on) an ashp as a solution, but perhaps that's not the right place to start?
    • CommentAuthornbishara
    • CommentTimeJul 8th 2019
     
    Sorry all! I went down with a chest infection, hence going awol. I really appreciate all your comments and I'm going to digest them properly tonight. Just for starters though..

    Yes, I thought 17k was crazy for air source too and it's helpful to know that wasn't just me. If you think that's bad, then you may be equally unimpressed by the 30k estimate for EWI. That does include a couple of months plastering all the internal plastering with breathable plaster, rather than what we currently have (and the plaster is so damp and mould (condensation, not rising damp) that I think replastering is inevitable anyway), as well as rendering on top of the EWI. and it is pavotherm (I think it's pavotherm - certainly wood fibre and breathable) but still...I think wtf is appropriate epithet.

    Oddly enough I have far from endless pockets and I have thought about just going for a less breathable insulation system (which would apparently be about 10k less) and relying on the mhrv to deal with any moisture in the walls - arguably we'd have to replaster as noted anyway and on that basis, might as well do a breathable plaster rather than something less so.

    I'm keen on underfloor downstairs, rads upstairs, although my partner thinks that we should have rads downstairs because cheaper (as we're replacing the suspended timber floor with concrete slab, I think there's less of a difference than there would be, but awaiting quote from builder to confirm).

    I'm sure that 8kw was the quoted heat load, but you make me think that I should double check. Architect has had health problems unfortunately and, as I always seemed to be last on his to do list anyway, I haven't spoken to him recently tbh - if nothing else, you make me realise that I need to!

    Oh, and central heating is ancient and all needs to be replaced including piping (I've had a few plumbers concur on that so tend to believe it). Not that I'm entirely sure that the 17k included that now I think about it.

    Any other ideas on heating welcome, but honestly we've driven ourselves crazy over the last few years trying to find an economically and environmentally viable ideal solution for us...and haven't found one, so gave up and went for "probably will work and won't cost a fortune (at least to buy)...hoping to use as little as possible" Not costing a fortune was before we got the quotes...

    GreenPaddy, thanks in particular for your comments. Can't help wondering if I'm doing this all wrong *bangs head against wall again* . Better to know now and build right though than steam ahead in ignorant bliss. Not sure that I was going to steam ahead though because I keep on thinking...HOW MUCH?!?!? ;-)

    hope that's a bit more context and thanks!
  7.  
    First thought about a heating system - are you on mains gas? If so IMO that would be a no brainer - go for a gas system. As was said above first understand what heating will be needed after the EWI etc.

    As for the EWI - I would go for EPS. cheaper than the exotic types and well known by the trades people. I would avoid the graphite type unless you are stuck for achievable U value with any thickness constraints because usually a thicker white EPS works out cheaper than thinner graphite EPS for the same U value. You have to do the sums and consider eves overhang etc..

    EPS is sort of breathable and I have put it up on a couple of stone/rubble/earth buildings (no dpc etc.) with no problems and (literally) millions across Europe over the last 30+ years can't be wrong about using EPS EWI. IMO the type of EWI (whether it is breathable or otherwise) will not alter the internal condensation issues. In one instance of mould that I had in a rented building (stone/rubble/earth building) EPS EWI solved a mould problem instantly - by keeping the wall warmer which stopped the condensation - no condensation = no mould.

    Unless the internal plaster is falling off or otherwise unsound I don't think condensation with its attendant mould should require the plaster to be replaced. Condensation and its attendant mould is, IMO, a ventilation and lifestyle problem. Replacing the plaster won't fix the problem, you will just get the mould back a few months down the line, - although since you are talking about MVHR it sounds like you appreciate the issues. I have fixed mouldy plaster with a good washing down with a strong hypochlorite bleach solution. Use the commercial stuff as used for washing down diaries etc. cheap and effective.
    • CommentAuthornbishara
    • CommentTimeJul 9th 2019
     
    Hi,

    thanks. Nope, no mains gas or I would totally agree :-(

    The plaster is falling off in places - I've done the mould with bleach countless times, but as you say, it's a recurrent problem unless you solve the underlying issues.

    I'm open to EWI suggestions but also aware that there have been huge problems with EWI on many properties for various reasons in the UK (I went to a whole presentation on it at Eco build one year) - and I would be surprised if that wasn't the case elsewhere. Lots of poor installation and detailing - which isn't breathability, but means that just because lots has been done, doesn't mean that I necessarily think it's been done well. I'm much more convinced by personal examples such as yours and Green Paddy's :-)

    more thoughts welcome!

    tania
    • CommentAuthornbishara
    • CommentTimeJul 9th 2019
     
    Green Paddy, very interested (and worried) about your comments re insulation. Makes me realise that I need to reacquaint myself with the details - but in principle it was as much wood fibre insulation as reasonable to the existing 9" solid walls - and we're going to extend the roof line at the front to get more in - plus replacing suspended timber floors with insulated concrete slab and obviously ensuring good loft insulation is in place that links up with the EWI. plus air tightness and MHRV.

    What type and thickness of EWI would you use with solid walls like mine? They are pretty pathetic in terms of inherent insulation value compared to lovely thick stone walls. I once calculated that a double glazed conservatory would be better and it looks like the 44mm wood walls of our new shed will be better too! :-(

    thanks,

    Tania
  8.  
    In my experience most or all of the problems with EPS EWI have been down to poor workmanship and or failure to attend to detailing. EPS has the advantage that there is no deterioration if it gets wet where as with something like wood fiber if it get wet it will suffer. Over the long term water can get into EWI through various failures or mechanical damage so using something that doesn't mind a bit of wet would make sense to me.

    I would go for 200mm EPS EWI as being a good compromise between an acceptable ROI and a better U value, but I am not up to speed with the UK building regs about the standard needed on a referb. Eaves overhangs also become a factor along with, on occasions, boundary lines.
   
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