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    • CommentAuthorGBP-Keith
    • CommentTimeNov 26th 2007 edited
    We are just preparing to go to press on the winter edition of GB mag and one particular story is worrying me. I would appreciate feedback from forum users on what they think of the story as I'm not sure whether to go ahead and publish or pull it. The author makes a lot of claims but is not very forthcoming with refs or examples that support his claims.

    Have a read please.

    • CommentAuthorJohan
    • CommentTimeNov 26th 2007
    I'm puzzled how he achieves a heating cost of only £60/annum if he's using a passive stack. Wouldn't you need a MVHR arrangement t oachive that?

    What does he back the claim that 'organic' insulation is more expensive then fibreglass with? The loose fill newspaper/wood fiber fills are pretty competative.

    Triple glazing is definitly not more expensive the double glazing. He's just used the wrong supplier!

    He's claiming a high level of airtightness. Yet a passive stack is suffienct ventilation? This sounds a bit confusing...

    What does he use for heating? As both condensing and biomass boiler as no good according to the author.

    On what basis is underfloor more efficient/cheaper to run the radiators?
    • CommentAuthorStuartB
    • CommentTimeNov 26th 2007
    I would also like to know what he uses for heating. It is ok saying you can achieve 14c in the winter but when one of your kids leaves the front door open for 10 minutes when its -5 then you will need some form of heating.

    I am currently trying to find the best solutions for a new build and I must say I agree with most of what he says. There are lots of solutions out there that can provide some of your 'eco' needs for most things but to invest in it all would cost a fortune. Performance of these solutions almost always fall below what the manufacturers suggest and they need to be more responsible in this area. The majority put profit before 'saving the planet' Fact.

    True he needs to provide more references but 90% of what he says I would agree with. My view now is to forget expensive underperforming partial heating solutions and to have the very best insulation you can afford. This seems to be a recurring theme in many discussions.
    • CommentTimeNov 26th 2007
    The article comes across as very negative as he spends so much time telling us what he didn't do and why he didn't do it so it appears a little too unbalanced I feel. Would want to see much more detail on what he did do. How does his DHW system work for example. What lighting systems has he got, etc.

    Any claim that this house is (nearly) zero carbon needs a lot more data to back it up.

    If you publish it then please fix the typos and make the keys to the graphs (p28) legible and put meaningful time marks on the x axis.

    (Not written by tony in disguise is it? :) )
    Johan asked ''What does he back the claim that 'organic' insulation is more expensive then fibreglass with? The loose fill newspaper/wood fiber fills are pretty competative?''

    Yes, but they are more expensive, whether we like it or not. They are closer in price than sheep's wool etc, but still more costly than (generally subsidised) min. wool.

    Posted By: Johan
    He's claiming a high level of airtightness. Yet a passive stack is suffienct ventilation? This sounds a bit confusing...

    It's quite troubling because he states that no blower-door tests have been made - so he really has no idea if his construction is airtight or not - fibreglass insulation is not airtight by any means and he states he uses "blob and dob" of the plasterboard on the inside and there's no mention of any airtight construction details. He briefly mentions MHRV at the end but it's not clear if he's using it or not.

    And his citation-free claims about the problems of condensing boilers are also worrisome.

    Paul in Montreal
    • CommentTimeNov 26th 2007
    The headline figures for heating, DHW and water are the reasons why the article sounds like a good read.

    In the end I thought it left nearly all questions unanswered.
    And I found myself questioning that any of the headline claims are in the least bit credible. In fact I would say that the are fantasy.

    There was even the fantastic claim of average roof insulation depths being 325mm based on some being 200mm(below building regs standard) being compensated by some at 500mm.
    Thats really clever.

    And he is also able to ventilate the building rapidly with a fan rated at 3W - oh yes really.

    This is a bad article, badly written, which adds nothing to green building and Keith, yes, you are right to question its value.
    I'm not sure what he says about the maximum cavity width being 200mm is correct. Isn't it the case that they used 250 or even 300mm at BedZed? Either what he says about the two skins acting independently structurally is wrong or it doesn't matter.

    I also think he should explain why he is using lightweight blocks with boards dabbed on for his inner skin, meaning the only serious thermal mass in a 3 storey house is in the ground floor slab. Presumably there is some reason for this but it doesn't sound like a very good strategy to me, particularly when he has invested in half a Cotswold hillside of thermal mass on the outside where it is only any good for looking at...
    • CommentAuthorjon
    • CommentTimeNov 26th 2007
    The nearly zero carbon claim appears to be far away from reality

    1: The U value quoted is, taking into account the windows, probably 100% higher than the minimum standard
    2: The property needs heating energy import and has no facilities to do otherwise
    3: There is no direct wire connection to micro gen and there is no microgen

    If you go to CfSH tech notes p29: The propery appears to fail each of the 4 tests listed

    It looks to me like a good, possibly level 4?, house.

    Some of the cost claims look a bit iffy but good on him if he's really done it.

    However, he makes some valid points. There is the question of whether or not we really need zero carbon (and whether or not the Government will back track when they realise the consequences of their proposals). Perhaps it would be better written from a developer's perspective but without reference to the actual house?
    • CommentAuthorguyc
    • CommentTimeNov 26th 2007
    Overall I liked the article, it is worth being read.

    As with any project what is rejected and why is important. I liked seeing his decision making in the article, but like ted I would of still liked a bit more of what he actually did. Maybe you can drop some of the stuff that has no references (e.g. the condenser boiler bullets) and replace it with a little more on what went into the house.

    What heating did he choose?

    Am I right that his internal temperature in winter dropped to 14c. Is this an acceptable temperature?
    • CommentAuthorhowdytom
    • CommentTimeNov 26th 2007
    I found an interesting, thought provoking article, unfortunately lacking far to much detail. I presume he wants us to buy his book to find out more !.
    I think it is a very provocative article, intended to advertise the project and to promote the design philosophy used. Putting that to one side, I found myself agreeing with quite a lot of the content, though like others here, I think the Author has got some things just plain wrong. Eg, taking cavity insulation down to formation level is a great idea-using an insulant which, shall we say, underperforms when wet, is not!

    I think you should publish the article, and maybe start a topic here where Mike Hillard could be invited to explain a little more, and to also give us some more references, and to show us the data which will be coming on stream soon. The proof will ultimately lie with the data, whether the building performs as stated or not. In any event, developments like this are to be comended.
    • CommentAuthorandytk
    • CommentTimeNov 27th 2007
    When I arrive at our office in the winter its frequently 14 degrees C and no this is not a comfortable or desirable temperature at all. I keep my outdoor jacket on until the temp guage has gone north of 18 degrees. Even then it feels cold.

    If this was an average semi detached and someone bought it the first thing they'd have to do is install a proper central heating system. Claiming that your heating bill is only £60/annum doesn't count if you're well below the temperature that will cause health problems for half the population.

    • CommentAuthortony
    • CommentTimeNov 27th 2007
    Just the sort of article we need.

    I wouldn't use passive stack ventilation. as Paul says.

    Thermal mass missing/wasted and it will be very air leaky as blobbed and dobbed. The bellows effect will tend to cool it too.

    Like the reasoned approach even if I disagree with some things

    Don't like the big conservatory

    Do very much like the insulation going down well below the floor -- I would have used batts loose fill tends to move arround, settle and miss bits on installation.

    Overall I enjoyed it.
    • CommentAuthorGBP-Keith
    • CommentTimeNov 28th 2007
    Thanks to everyone for their feedback. We have put in place some of the points raised here but the story still poses as many questions as it answers but I have decided to publish and the final story in in a new thread called 'Realising a vision'. Please feel free to start questioning the content and I'll do my best to get the author to respond or at least provide me with the answers so I can post the.
    • CommentAuthorTuna
    • CommentTimeNov 28th 2007
    Some rather questionable logic in places, and it seems a good part of the evidence that he does supply is anecdotal, despite the neat looking graphs. For instance he states the rapid cooling time having let the house reach 40 degrees on an August day. Firstly, it's worrying that a highly insulated house could reach that temperature in a day, so I hope he was giving the temperature of the conservatory. Secondly, if that's heat due to solar input the air temperature could have been uncharacteristically low, so opening windows is bound to have a rapid effect. There are also confusions between measured performance and expected performance - in some places he states figures for previous seasons, and in others he mixes figures that he expects to see in future. One is a fact, the other is a guess.

    The biggest problem I have with the article is that it is presented in the first person and effectively is an opinion piece. However, it's trying to present itself as factual, which it most definately isn't. Some of his conclusions are quite sound - builders do tend to have a rather more pragmatic approach to eco-friendly building than green theoreticians. However, some of them appear to be based on personal predjudices and guesswork. The whole piece would come off better as being either an independent assesment of what he's done (with suitable explanations and detail) or as an opinion piece of what he believes works - but not as both.

    I did like the bit where he described his home automation set up as "powerfull looking". :D
    • CommentAuthorandytk
    • CommentTimeNov 28th 2007
    And another thing on temperature.

    He claims that the automated system managed to reduce the temp by 9 degrees from 40 C.

    I'm sorry but thats not all that impressive. That still leaves you with a house at 31 C which is far from comfortable. Again if that house is sold to someone with money (and it almost undoubtedly will) then the first thing they will do is install A/C.

    I know I would if my house got that hot regularly in the summer.

    And after criticizing almost all forms of space heating he then fails to mention which one he is actually using?????


    • CommentAuthorGBP-Keith
    • CommentTimeNov 30th 2007
    Further comments on this story need to be posted here please:

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