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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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    • CommentAuthorTriassic
    • CommentTimeOct 23rd 2013 edited
     
    Dr Jones believes the only way to cut domestic carbon emissions by the required 29 per cent is by legislation and compulsory energy efficiency standards.

    In his talk ‘Green Deal or No Deal’ at the Retrofit East conference in Cambridge he will say that the Green Deal is a busted flush....

    To meet the Government’s carbon reduction targets, the UK needs to retrofit 700,000 properties per year. However, despite being allocated a fund of £244 million, only 12 properties have so far had any work completed under the Green Deal finance scheme....

    “The only way to achieve the scale of change necessary is through legislation and compulsory standards. The Government should again look at using Energy Performance Certificates as a basis for creating minimum standards for all homes that are sold or renovated.”

    http://www.businessweekly.co.uk/cleantech/16057-scrap-green-deal-says-climate-change-expert
    • CommentAuthortony
    • CommentTimeOct 23rd 2013
     
    I agree as far as the the last sentence above but then the measures should be applied across the board not only sold or renovated or presumably re-tenanted.

    There are existing building regulations that are virtually never used or enforced concerning renovations.

    I agree about the Green Deal, aint working nor was it ever going to as I said at the time.
    • CommentAuthorMike George
    • CommentTimeOct 23rd 2013 edited
     
    The Green Deal is dead in the water as far as insulating hard to treat homes is concerned. It just is not going to happen

    The only way to insulate hard to treat homes is to reduce the ridiculous u-value requirement to a level which is technically feasible and consequently affordable.

    If every house had a minimal amount of insulation installed externally to a u-value of say 0.5 then the savings realised would be massive. Typically around 60%.The additional insulation currently required above and beyond this has a minimal return and is prohibitively expensive in most buildings due to the consequential works - extending eaves, moving soil pipes etc. That's without considering planning/boundary complications

    Wake up politicians and realise that this is the only way forward The choice is:

    Do a lot to a little (Green Deal)
    or a little to a lot (No Green Deal)

    And the question to ask is: Which of these will result in the greater savings?
    • CommentAuthorjamesingram
    • CommentTimeOct 23rd 2013 edited
     
    I'm half with you Mike , I'd have thought U < 0.3 is relatively easy to achieve on majority of homes
    What annual delta T ( the K bit of Wm2K ?:smile: ) did you use for your estimator in green building bible
    I just tried k = 20 deg C for 60 days which seems a bit over the top
    here
    http://www.greenbuildingforum.co.uk/forum114/comments.php?DiscussionID=11296&page=1#Item_12
  1.  
    Yeah, I agree 0.3 is possible, though obviously 0.5 is easier still - especially for houses with no soffits.

    I didn't use steady state calcs for my estimate - I used TAS to dynamically simulate different scenarios over a year - and to be honest the 60% Is an approximation based on many variations both myself and students have simulated.

    If you think about it though you don't need to consider the delta T as you are comparing a difference in wall properties for a specific time period. Simplistically:

    Assuming a solid wall has a u-value of 1.5W/m2K

    A reduction in the u-value from 1.5W/m2K - 1W/m2K realises saving of 33%
    A reduction in the u-value from 1.5W/m2K - 0.5W/m2K realises saving of 66%
    A reduction in the u-value from 1.5W/m2K - 0.3W/m2K realises saving of 80%
    A reduction in the u-value from 1.5W/m2K - 0.15W/m2K realises saving of 90%

    When you consider the incremental cost (and thickness) of each improvement its not hard to see where the optimum lies, or indeed which of the above would realise the kind of savings required for the existing stock in a speedy way.
    • CommentAuthortony
    • CommentTimeOct 23rd 2013
     
    There is a time factor involved and I'm not for less than 0.3 for renovation of walls.
    •  
      CommentAuthorSteamyTea
    • CommentTimeOct 23rd 2013
     
    Yes, the Green Deal does seem to be an all or nothing method of reducing energy.
    One disadvantage of reducing everything to a price, and then charging interest on that.
    you and Yours said they would get Ed Davey back and question him on the 'success' of it in the new year. Should be fun :bigsmile:
  2.  
    Posted By: tonyThere is a time factor involved and I'm not for less than 0.3 for renovation of walls.


    What do you mean about the time factor tony?
    • CommentAuthorMike George
    • CommentTimeOct 23rd 2013 edited
     
    A hypothetical question :

    If you could insulate every house (walls) in the UK to 0.5W/m2K in twenty years.
    Or half of the houses in the UK to 0.3W/m2K in twenty years
    Or a tenth of the houses in the UK to 0.15W/m2K in twenty years.

    Which would realise the greater savings?
    • CommentAuthortony
    • CommentTimeOct 23rd 2013
     
    The time factor I mentioned was to with the length of time the house stands for (conversely how long it is heated before it is insulated properly)
    •  
      CommentAuthorSteamyTea
    • CommentTimeOct 23rd 2013
     
    What sort of houses and where are they, What is the starting value?
    Insulating down here on the coast would have a lesser affect than up in the Yorkshire dales.
    Or is this an even mix of what is available.

    At a guess I would say that every house to 0.5 in twenty years as houses tend to last longer than that.
    So if it was measured over 60 years, then you are only loosing out at the start.

    But a good question
    :bigsmile:
  3.  
    Posted By: SteamyTeaWhat sort of houses and where are they, What is the starting value?
    Insulating down here on the coast would have a lesser affect than up in the Yorkshire dales.
    Or is this an even mix of what is available.

    At a guess I would say that every house to 0.5 in twenty years as houses tend to last longer than that.
    So if it was measured over 60 years, then you are only loosing out at the start.

    But a good question
    :bigsmile:" alt=":bigsmile:" src="http:///forum114/extensions/Vanillacons/smilies/standard/bigsmile.gif" complete="complete" >


    If we said uninsulated houses pre 1975. So about 80% of the existing stock - all uninsulated (as built).

    I only said twenty years as I think it will take at least that long to achieve anywhere near a target for insulating walls in all of them.

    But that doesn't really matter - its about cost - and thereore likely take up. If regulation were relaxed and a 0.5 target were established - then the take up under a scheme like Green Deal would be enormous. As would private installations.

    Part L1b is actually having a negative effect in my view as people either cannot afford to have the work done or it is technically too complex. In addition such requitrements are actually creating problems in some houses (as per Breaking the Mould thread)
    • CommentAuthorleakyPipes
    • CommentTimeOct 25th 2013
     
    <blockquote><cite>Posted By: SteamyTea</cite>Yes, the Green Deal does seem to be an all or nothing method of reducing energy.
    One disadvantage of reducing everything to a price, and then charging interest on that.
    you and Yours said they would get Ed Davey back and question him on the 'success' of it in the new year. Should be fun<img src="/forum114/extensions/Vanillacons/smilies/standard/bigsmile.gif" alt=":bigsmile:" title=":bigsmile:"></img></blockquote>

    The problem is the interest rate, if it was halved to 3.5% then it would be many many times more successful.

    The government can currently issue 30y gilts at 3.5%, so why not pass on these low interest rates?

    It's not as if the borrowing would go towards benefits, tax breaks or military procurement, but securing a relatively cheap and permanent way of reducing the countries energy bill, energy imports and balance of payments.

    Time for the government to wade in on a big scale and provide the economies of scale that only big government can provide, even though this is anathema to all of the political parties.
    • CommentAuthortony
    • CommentTimeOct 25th 2013
     
    we have to wonder why thy haven't done this already then.
    • CommentAuthorleakyPipes
    • CommentTimeOct 25th 2013
     
    Because the government is not prepared to subsidise the green deal to any meaningful degree, the interest rate is set at 7% to cover running costs and future interest rate rises because they don't want the borrowing on the balance sheet.

    Funny how they are quite prepared for us to pay over the top for new nuclear, when the money would be much better spent on energy efficiency measures. But there again, your average joe on the street doesn't tend to offer cushy consultancy work when you lose your seat.
    •  
      CommentAuthorSteamyTea
    • CommentTimeOct 25th 2013 edited
     
    Posted By: leakyPipesBut there again, your average joe on the street doesn't tend to offer cushy consultancy work when you lose your seat.
    Thankfully the general public don't have to, they have voted with their wallets :bigsmile:
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