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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.

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    Made a start on getting a SAP EPC done for the barn conversion, as we need one for Building Regs and also to claim the RHi for the Ground Source Heat Pump system.
    It's only a draft at the moment because it isn't quite finished yet, but I was delighted that it came out at a "B"

    Better than the "C" that we got for the last place we did (of similar solid stone wall construction)

    The only thing we could have done better on would be PV but the roof is East/West and I don't think we have any room inside for invertor(s) but I would not rule it out in the future.
      EPC recommendations.jpg
    The Passivehouse website says:
    Primary Energy Demand
    not to exceed 120kWh annually for all domestic applications (heating, cooling, hot water and domestic electricity) per square meter of usable living space.

    the draft SAP EPC says:
      Primary Energy Use.jpg
    I don't know if they are the same thing?
    But in any case, I don't think we are near the 15kWh per square metre per annum for space heating alone.
    • CommentTimeNov 23rd 2021
    Posted By: Dominic CooneyThe Passivehouse website says:
    Primary Energy Demand
    not to exceed 120kWh annually for all domestic applications (heating, cooling, hot water and domestic electricity) per square meter of usable living space.

    Which Passivehouse website is that?

    According to https://passivehouse.com/ (the PHI website) and specifically https://passivehouse.com/02_informations/02_passive-house-requirements/02_passive-house-requirements.htm "The Renewable Renewable Primary Energy Demand (PER, according to PHI method), the total energy to be used for all domestic applications (heating, hot water and domestic electricity) must not exceed 60 kWh per square meter of treated floor area per year for Passive House Classic."

    There's also some discussion of standards at https://passipedia.org/basics/energy_and_ecology/primary_energy_quantifying_sustainability

    PH originates from German standards, which differ from SAP / BRE methodology so any resemblance between the numbers would be pretty much coincidental.

    But anyway, well done on your EPC result :)
    I saw it here, only looked in one place because I was looking for interest how far off passive standards we are:

    • CommentTimeNov 23rd 2021
    Dunno why they're using old criteria (replaced in 2015). The link above the table goes to the authoritative page and that links to a comprehensive PDF if you or anybody else is interested.
    I have downloaded the pdf ready for the next project!
    Nice! SAP 2012 (used for EPCs) uses rather out-of-date figures, including a primary energy factor of 3.02 for electricity. IE it assumes that each 1 kWh of electricity that you buy, will take 3.02 kWh of primary energy to make, in line with the low thermal efficiency of the power stations back then.

    The updated figure in forthcoming SAP 10.2 is 1.50, half as much, reflecting the reduction in coal power stations and increase in wind/solar electricity, which are assigned a much better primary energy efficiency.

    If in future your EPC is redone with SAP 10, the primary energy demand reported on the certificate should get even better than you already have!

    Likewise the carbon emissions of the energy used in the building should get even better, in line with the national reduction in carbon intensity.

    I don't know how PH handles all this sorry. I understand there are differences with SAP how they handle electricity imports vs electricity generated on site, and building energy consumption vs heatpump electricity consumption.
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