Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)

Categories



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.

Buy individually or both books together. Delivery is free!


powered by Surfing Waves




Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.




  1.  
    • CommentAuthortony
    • CommentTimeOct 19th 2021
     
    Insulation upgrades are needed and even then existing radiators might not work sufficiently well leading to further disappointments.

    I think the costing are further apart than 5k and the help level the playing field insulation upgrades should become mandatory on boiler replacement too.
    • CommentAuthorJonti
    • CommentTimeOct 19th 2021
     
    Just another big budget scheme done to make it look like the government is doing something but in the end very few will take it up and many of those who do will face poor advice and shoddy installation work. In the end it will be quietly dropped. Better the drive was towards better insulation.
    • CommentAuthortony
    • CommentTimeOct 19th 2021
     
    +1
  2.  
    The EU has just announced a similar grant for heat pumps except that it is up to 25k and with the heat pump you have to install 5 kWp PV and battery storage as well and have windows and roof insulation to current standards (but windows and roof can be included in the grant).
    There is also a smaller grant for PV only.

    Is Brexit trying to keep up the EU or the EU trying to keep pace with Brexit. I don't believe each came up with the same idea independently and at the same time.

    And of course the usual amount of small print gotchas on the back page of the grant.
    • CommentAuthorrevor
    • CommentTimeOct 19th 2021
     
    Posted By: JontiBetter the drive was towards better insulation.

    Totally agree.
    Insulation cost is a locked in once off cost it reduces the amount of energy used regardless of the source. Has anyone added up the energy in the gas and oil that will be transferred to electricity and worked out where it will all come from and whether the infrastructure will support it? not seen anything. Conservation of energy regardless of source has to be the prime consideration. I have spent thousands on insulation and other approaches to get as close as possible to a zero energy house. Currently I am at about 8.5p per sq ft per annum and that is with LPG in bottles. I have no idea how it compares to the "norm" except I do know my energy costs are much lower than my neighbours.
  3.  
    The pot announced today is apparently going to be £3.9bn of which 'only' £0.45bn is for heat pumps, much of the remaining £3.4bn will be for insulation (which hasn't grabbed the headlines). Target is EPC band C by 2035 for "as many homes as possible". (In England I think).

    The govt recently tried dishing out £10k grants for insulation under the Green Home Grant scheme, was a bit of a disaster. But those £10k grants are still available through local councils, means tested.

    It's not either/or AIUI - a super insulated home running on LPG won't meet net zero, and an uninsulated home would be expensive to heat with a heatpump. So they need to push both insulation and heatpumps. Sounds like replacement gas/LPG boilers will be stopped from 2035 but bit vague.

    Notably they are not pushing hydrogen in this strategy, putting any decisions off til 2026.

    https://www.gov.uk/government/news/plan-to-drive-down-the-cost-of-clean-heat
  4.  
    The Scotland version was published recently,
    - all existing houses to be EPC C by 2033
    - no new/replacement gas boilers from 2030
    https://www.gov.scot/publications/heat-buildings-strategy-achieving-net-zero-emissions-scotlands-buildings/

    Also propose to revamp the EPC system which seems biased towards gas heating.
    • CommentAuthorrevor
    • CommentTimeOct 19th 2021
     
    I am hoping that common sense will prevail at some point. It seems perverse that I produce less CO2 in a year than one return flight to Europe by those in poorly insulated homes who prefer to spend their money on foreign holidays than insulate their houses. We should all have a carbon allowance target to meet and choose what is best for the individual.
    •  
      CommentAuthordjh
    • CommentTimeOct 19th 2021
     
    Posted By: revorWe should all have a carbon allowance target to meet and choose what is best for the individual.

    I like the spirit of that idea. Responsibility for individuals.
  5.  
    Snippet from the Scottish version:

    The number of homes at EPC 'C' or above has increased from 18% in 2010 to 45% in 2019. That's better progress than I expected, and encouraging if it continues.

    However only 15% of non-domestic buildings were EPC C in 2019, much worse.
    • CommentAuthorphiledge
    • CommentTimeOct 19th 2021
     
    Posted By: djh Responsibility for individuals.

    +1

    A climate levy on every building proportionate to a combination of current council tax bands and EPC rating. Level increase for first 5-10 years and increasing exponentially thereafter. Should get things moving😁
    •  
      CommentAuthordjh
    • CommentTimeOct 19th 2021
     
    Posted By: philedgeA climate levy on every building proportionate to a combination of current council tax bands and EPC rating.

    I've stated my attitude to EPCs often enough before, so you can guess what I think of that idea! And I'm not quite sure what council tax has to do with it? Who pays the levy if the occupant is exempt, or benefitting from one of the discounts? Is the owner or the occupant of the building liable?
    •  
      CommentAuthorfostertom
    • CommentTimeOct 19th 2021
     
    I was struck by the £3.9bn figure, amazed it was comparable with Biden's Reconciliation (Infrastructure) bill which is struggling to be born against Republican resistance. Until I realised that Biden's is $3tn!
    • CommentAuthorMike1
    • CommentTimeOct 19th 2021
     
    Posted By: WillInAberdeen£0.45bn is for heat pumps
    ...and that's over 3 years. So 30,000 homes / year if they were all to get the full grant...
  6.  
    https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/922660/EPC_Action_Plan.pdf

    What the UK gov thinks are wrong with EPCs.
    Scot gov has other ideas.

    "The rating of EPCs will begin to have a financial value... EPCs therefore need to be [changed, so they become] accurate, reliable and trusted. "
    • CommentAuthorJonti
    • CommentTimeOct 19th 2021
     
    £10K grants are no good if most people either cannot meet the criteria or the only type of work offered is not suitable. The fact is that the recent UK deal was canned after a short time having been roundly ignored by most. Holyrood has a habit of producing reports and plans but are far worse at implementation. The proof will be in the pudding on this one as well.
    • CommentAuthortony
    • CommentTimeOct 20th 2021
     
    Half baked but the threat with teeth (no new gas boilers after 2030 oops 2035 is a change) but still isn’t going to work though has generated a lot of interest among my friends
  7.  
    https://www.homeenergyscotland.org/find-funding-grants-and-loans/interest-free-loans/overview/

    Hi Jonti, have you tried this? Scottish gov scheme, you can borrow interest-free for insulation, eg £10k for EWI or £17.5k for renewables/heatpump. They convert 40% to 75% of the loan into a grant, or more if you are on pension or benefits. Seems pretty complicated.
    •  
      CommentAuthordjh
    • CommentTimeOct 20th 2021
     
    Posted By: WillInAberdeenWhat the UK gov thinks are wrong with EPCs.

    Thanks for the link; hadn't seen that before.

    Completely misses the point as far as I can tell, though. "An EPC system that produces accurate, reliable and trusted EPCs" - well absolutely and I'm sure that fraud and cheating is a major issue that needs to be fixed, but it doesn't fix the basic issue that they are garbage!
    • CommentAuthorrevor
    • CommentTimeOct 20th 2021
     
    Posted By: djhbut it doesn't fix the basic issue that they are garbage!


    From my limited experience of having one and trying to get one totally agree.
    • CommentAuthorRobL
    • CommentTimeOct 20th 2021
     
    I think I’ve posted this rather sad graph before, which shows almost no correlation between an EPC and reality, but here it is anyway, source:
    https://www.researchgate.net/figure/Actual-versus-SAP-estimated-energy-consumption_fig3_280986564
      BFFF0FAC-3A64-4B5E-BA50-BD98DC3B4655.png
    •  
      CommentAuthordjh
    • CommentTimeOct 20th 2021
     
    Posted By: RobLI think I’ve posted this rather sad graph before, which shows almost no correlation between an EPC and reality

    Yup, but it's not just that. My PH scores a 'C' on the EPC and their only suggested improvement is to install solar thermal, as well as the PV it already recognizes I have, which it says will improve my EPC by a whole ONE point to 'C'! Nothing at all about improving my 'very poor' heating system with something snazzy like a heat pump, which might just possibly do something further.
  8.  
    That data was from 1996, but the picture is probably still the same now! Interesting paper.

    They note that everyone is confusing:

    1) Heating Costs (which are the EPC A-G ratings, they favour cheap gas heating), with

    2) Energy Usage (which the Scottish gov propose to replace the EPC ratings with), with

    3) CO2 emissions (which is what we should actually care about, and are using wildly out-of-date grid intensity data that penalises renewable electric heating).


    They also note that the EPC survey is very inaccurate at predicting any of these numbers . Possibly "actual" energy usage from smart meters could be quoted instead (as the UK gov just proposed) but that could be just as random depending on occupancy etc.

    If we switch from oil heating to ASHP, our heating costs should get worse, our energy usage should stay the same, our primary energy imports should decrease drastically, and our CO2 emissions should almost disappear. Difficult to show all that on a simple A-G scale!

    It didn't help that whoever did the EPC for our house, entered the floor area in square feet instead of square metres, so the ratings are completely barmy. As it was paid for by the previous owner, we have no comeback.
    •  
      CommentAuthordjh
    • CommentTimeOct 20th 2021
     
    I just noticed another recent contribution to the debate: https://www.passivhaustrust.org.uk/guidance_detail.php?gId=44

    Perhaps not surprisingly, it's not a fan of EPCs.
    • CommentAuthorJonti
    • CommentTimeOct 20th 2021
     
    Posted By: WillInAberdeenhttps://www.homeenergyscotland.org/find-funding-grants-and-loans/interest-free-loans/overview/" rel="nofollow" >https://www.homeenergyscotland.org/find-funding-grants-and-loans/interest-free-loans/overview/

    Hi Jonti, have you tried this? Scottish gov scheme, you can borrow interest-free for insulation, eg £10k for EWI or £17.5k for renewables/heatpump. They convert 40% to 75% of the loan into a grant, or more if you are on pension or benefits. Seems pretty complicated.


    Thanks WiA. I will look at this when I have time.
  9.  
    Posted By: djh
    Posted By: RobLI think I’ve posted this rather sad graph before, which shows almost no correlation between an EPC and reality

    Yup, but it's not just that. My PH scores a 'C' on the EPC and their only suggested improvement is to install solar thermal, as well as the PV it already recognizes I have, which it says will improve my EPC by a whole ONE point to 'C'! Nothing at all about improving my 'very poor' heating system with something snazzy like a heat pump, which might just possibly do something further.

    My PH had an EPC of A95 without any PV. The inaccurate EPCs could be the result of poor assessors although I always preferred to believe the PHPP results.
  10.  
    >>>>>My PH scores a 'C' on the EPC
    You could improve your score by fitting a coal stove - SAP thinks they are cheaper to run than electric heating.

    >>>> another contribution to the debate: https://www.passivhaustrust.org.uk/guidance_detail.php?gId=44

    Interesting. It raises the same complaints about EPCs as we all discussed, but then they propose a system which seems to have all the same problems. Your coal-heated PH would be given the same rating if it had a renewable-electric-heatpump, and both ratings would still depend on a brief survey to uncover how exactly the house works thermally. Seems it is difficult to find a better system.

    Following the references, it seems all the building modelling methods struggle with the variability of people - when a group of houses (that have been modelled to use similar amounts of energy) are measured in real life, there is a wide spread of actual usages, because of how different occupants live, like in RobL's graph. So a Standardised Assessment will not match reality and people shouldn't be led to expect that.
    •  
      CommentAuthordjh
    • CommentTimeOct 21st 2021
     
    Posted By: PeterStarckMy PH had an EPC of A95 without any PV.

    Ooh, jealous :devil:
    The inaccurate EPCs could be the result of poor assessors although I always preferred to believe the PHPP results.

    I certainly believe that PHPP accuracy has been confirmed many times. Anecdotally, it seems to work well for ours. I definitely tust it more than SAP and would always use it as a design tool in preference.

    But I've been seeing publications recently that suggest SAP isn't awful in many cases, and that its errors are due to things like it assuming an average climate whilst PHPP takes account of regional variations and other underlying assumptions. RdSAP is just awful, of course - it makes far too many assumptions.

    There are some efforts to reduce the duplication:
    https://aecb.net/sap-and-phpp-two-approaches-one-goal/
    https://www.ribaj.com/products/phpp-and-sap-energy-performance-calculations-passivhaus-aecb-elmhurst-energy

    (what's with the weird font in the RIBA article, BTW?)

    Then the not-too-bad-but-not-brilliant SAP calculations are put through the EPC shredder and the results can be meaningless. I skimmed through the SAP results for my house last night and could see a few odd things: PV generating about half of reality, one door with a U-value of 3 whilst everything else has 0.7 (also unrealistic), and doors and windows apparently not matching reality, total heating requirement way more than reality etc. But I don't know whether those problems are a result of the assessor putting data in wrong, or SAP calculating wrong.
  11.  
    It's good to have a designer's SAP model that is still in date (or PHPP) but the vast majority of UK homes are older than 10yrs, so they will need an assessment that can be created from simple survey data (and/or energy bills).

    We should probably expect to pay more for a better EPC survey, but realistically the surveyor can't core holes through all the walls to check the buildup, or do conductivity tests on all the windows to see if they still hold argon. So there will have to be assumptions of some kind.

    This study of 97 UK PHs found that the individual houses used +-100% more or less energy than their PHPP predictions, but the average of all 97 was quite close to the average of their predictions. So the software is reliable on average across large groups of houses, but not so good for any individual house.

    DOI: 10.1016/j.enbuild.2020.110240
      Screenshot_20211021-112914.png
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press