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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

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  1.  
    Was just reading up on the proposed next version of the SAP rating system, SAP10.

    The most significant change seems to be that the CO2 intensity of electrical heating will be dramatically reduced from 0.519 to 0.233kg/kWh, in line with the changes in the UK grid.

    This means that electric heated houses (including heat pumps etc) will get much better EI and DER ratings than they currently do, so favouring people building electric rather than gas heated. This might be cheaper to build but have higher running costs.

    Conversely, the CO2 (and £) savings from solar PV will reduce, so slapping some PV onto the house will not give as much improvement to the rating.

    Has anyone looked into the new system yet, any insights?

    https://www.google.com/search?q=sap+10
    •  
      CommentAuthordjh
    • CommentTimeMay 16th 2019
     
    Posted By: WillInAberdeenThe most significant change seems to be that the CO2 intensity of electrical heating will be dramatically reduced from 0.519 to 0.233kg/kWh, in line with the changes in the UK grid.

    The whole thing seems to have been updated. I also liked the disavowal of ACDs - that might actually prompt some new designs.

    I understand why the CO2 savings from PV will reduce, but why the £?

    So a definite improvement, IMHO, but still something to be regarded as a box-ticking game that has to be won rather than a useful tool.
  2.  
    £ value of PV exports will decrease from 13.19p/kWh to 3.8p/kWh, apparently, reflecting no more FITs.
  3.  
    <cite>Posted By: djh</cite>still something to be regarded as a box-ticking game that has to be won rather than a useful tool.


    Certainly not critical for houses like yours, but for mass market houses this stuff is important, as it is used for determining building standards compliance and EPCs, whether realistic or not.

    Eg - if a developer designed a gas-heated house that met building stds TER, they could switch to an electric heat pump (cop of >3) and miss insulation out, to a ~3x poorer U value, and still claim the same emissions rate. Or leave the insulation in, cancel the ufh plumbing and fit electric panel heaters instead. The buyer would be left with the running costs. Hope the next building stds update stops this somehow before SAP10 comes in.
    (Edit- I can see some bits in the Scottish stds that would stop this)

    For an existing house with PV and an EPC, if the EPC is redone, the new EPC rating will come out different, as less credit is given for the PV (probably other changes too)
    •  
      CommentAuthordjh
    • CommentTimeMay 17th 2019
     
    Posted By: WillInAberdeenEg - if a developer designed a gas-heated house that met building stds TER, they could switch to an electric heat pump (cop of >3) and miss insulation out, to a ~3x poorer U value, and still claim the same emissions rate. Or leave the insulation in, cancel the ufh plumbing and fit electric panel heaters instead.

    If that's a more accurate representation of reality, then so be it. Ditto the rerating of EPCs, though care is obviously needed in the accompanying legislation not to make illegal something that was legal when it was done.

    The buyer would be left with the running costs.

    That's a whole different question. SAP is 'the methodology used by the Government to assess and compare the energy and environmental performance of dwellings. Its purpose is to provide accurate and reliable assessments of dwelling energy performances that are needed to underpin energy and environmental policy initiatives'.

    Nothing about economics there; quite correctly in my view. Any regulations about running costs should be a completely separate piece of legislation - it's social policy. And it's not as simple as an outright ban - my heating is simple electric resistance heating and I'm quite happy and wouldn't want to be prevented from doing it again. Maybe in a few years economics and technology will have changed circumstances so I might reconsider, but not for the present.
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