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Energy Assessment: Domestic Energy use per square metre?

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    • CommentAuthortony
    • CommentTimeMar 18th 2011
     
    Do any of us have any figure for domestic energy use per square metre for houses in England?

    Ideally I would like some for typical Victorian terrace, 1960's semi and a new three bed house built to satisfy current building regs

    thanks -- answers in W/m2/y please
    •  
      CommentAuthorDamonHD
    • CommentTimeMar 18th 2011
     
    1 kWh of gas for DHW/CH is nothing like 1kWh of electricity; I don't know why PassivHaus mixes them for example.

    I have numbers for my '60s end-of-terrace timber frame before and after improvement, but the last few winters are going to skew numbers a little. You might want to normalise by HDD.

    Rgds

    Damon
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 19th 2011
     
    Posted By: DamonHD1 kWh of gas for DHW/CH is nothing like 1kWh of electricity

    Not sure I understand why they are not the same. If they are both converted to heat and system efficiencies are taken into account then they are the same, cost is a different matter.
  4.  
    Domestic energy factfile - energy efficiency of the British housing stock http://bit.ly/cPSttK #info #green #building
    might be something in here

    ST -i think Damon might be think of CO2/kw differnece between grid electric and grid gas
  5.  
    http://www.energysavingtrust.org.uk/Publication-Download/?p=1&pid=249

    page 1 offers pie chart of energy usage brake down of 3 types but not kW/m2/y
    •  
      CommentAuthorDamonHD
    • CommentTimeMar 19th 2011
     
    1kWh of electricity can, for example, provide several kWh of heat with a heat-pump.

    Electricity is a far far higher grade of energy than gas/heat. Mixing them is apples and oranges.

    Rgds

    Damon
    • CommentAuthorjamesingram
    • CommentTimeMar 19th 2011 edited
     
    http://www.ukstudentpassivhausconference.org.uk/uploads/4/7/2/1/4721930/paschal_volney.pdf

    page 6

    typical space heating demands

    pre 1945 250 kWh/m2/y
    1965-76 200 kwh/m2/y
    2000- 150 kWh/m2/y
    •  
      CommentAuthorSteamyTea
    • CommentTimeMar 19th 2011
     
    Posted By: DamonHDMixing them is apples and oranges.

    I know what you mean as we 'obey the laws of thermodynamics' in this forum, but it is possible to to design and run a gas heat pump, we had a gas fridge in our caravan when I was a kid, there the term 'avec vous une T-Piece' comes from, it was so we could cook and cool at the same time.

    A Watt is the product of the force required to move a kilogram one meter (a Joule) in one second. 3600 Watts is a kWh, it is just a descriptor of something real and is fuel independent. It is why it is used.
  9.  
    I think PM's heat pump is gas run
    • CommentAuthortony
    • CommentTimeMar 19th 2011
     
    Thanks James -- real numbers at last!!
  11.  
    Yes , a good power point on Energy efficient refurb , figures , worth a read
    looking at the case study for a solid wall semi ( probably 1960-) it gives a figure of
    Space Heat Demand : 401 kWh/m2 yr
    so not sure how typicial the other table they quote is ? They do seem a little low to me

    it gives a resource link of "Table extracted from Kyoto in home (www.kyotoinhome.com)"
    • CommentAuthorqeipl
    • CommentTimeApr 5th 2011 edited
     
    Mine works out around 60 for electricity and another 15 for wood/coal = 75kWh/m^2/year.

    Edit: but some of that electricity goes into the workshop so maybe 70kWh/m^2/year for the house.
    • CommentAuthorpmcc
    • CommentTimeApr 5th 2011
     
    Timber frame detached 1974 rural central Scotland 181m2: 32 electricity + 57 LPG = 89kWh/m2/year
    • CommentAuthortony
    • CommentTimeApr 6th 2011
     
    Thanks guys

    Anyone know what a typical house built to current building regs would be?
    • CommentAuthorqeipl
    • CommentTimeApr 6th 2011
     
    My house is built to current regs (Scotland).
    Energy performance certificate shows "Approximate current energy use....98kWh/m^2"
    Energy efficiency rating C72
    Environmental impact rating B90
    • CommentAuthortony
    • CommentTimeApr 6th 2011
     
    is that heating energy or total energy?
    • CommentAuthorqeipl
    • CommentTimeApr 6th 2011
     
    It's total energy.
    I've tried digging through the SAP calculations to find out what proportion is heating but can't understand the workings and have come up with figures as diverse as 40 and 104kWh/m^2.
    Sorry.
    • CommentAuthorjamesingram
    • CommentTimeApr 6th 2011 edited
     
    dont forget if you're using UK grid electric to convert it to primary energy , to give a true figure of energy used .
    0.36 kW grid electric = 1 kW of primary energy

    so UK grid electric x 2.78 = primary energy usage

    ( please let me know if you think this conversion figure is incorrect )
    •  
      CommentAuthorDamonHD
    • CommentTimeApr 6th 2011
     
    I think that you could argue about the exact number, but it's massively better than assuming 1kWh electricity is the same a 1kWh of heat from burning gas for example.

    FWIW I think that anything near 3 is probably about right for various reasons.

    Rgds

    Damon
    •  
      CommentAuthorSteamyTea
    • CommentTimeApr 6th 2011
     
    • CommentAuthorjamesingram
    • CommentTimeMay 15th 2011 edited
     
    just dug up and old AECB year book 06/07
    had this info in it for kWh/m2 yr , delivered energy + electricity, domestic usage

    average stock - 278 , DTI 2003 figure

    odpm ADL1-2002 - 130 , - 209? estimate of real use by AECB
    odpm ADL1-2006 - 99 , - 183 ? ""
    CSH1 - 183
    CSH2 - 135
    CSH3 - 84 AECB silver
    CSH4 - 38 AECB gold
    CSH5 - 38
    • CommentAuthortony
    • CommentTimeMay 15th 2011
     
    Are those for heating only or for all energy uses?
  23.  
    all energy uses
    • CommentAuthortony
    • CommentTimeMay 15th 2011
     
    That puts AECB Silver and CSH 3 or more better than Passive Haus and Minergie which comes as a surprise to me
    •  
      CommentAuthorSteamyTea
    • CommentTimeMay 15th 2011 edited
     
    I am currently using (last week) 57 kWh.m^-2.y^-1
    Of which 23 is DHW and 33 is all the rest.
    That puts me at about CSH 3.5 (would that be silvered up gold or silvered down gold?)
    Obviously no heating last week, going to try and find the data for that now.

    1987 built terrace.
    • CommentAuthorjamesingram
    • CommentTimeMay 15th 2011 edited
     
    Tony
    i think this 2006 table is described as a AECB proposed pathway to zero carbon homes via CSH and has been replaced by http://www.aecb.net/PDFs/carbonlite/AECB_VOL3_EnergyStandard_V6FINAL.pdf
    see page 3

    The passivhaus 15 kWh/m2 yr space heating and 120 kWh/m2 yr primary energy target seems odd to me ,
    I presume its the builidng fabric and space heating area that PH is really interested in , and designed to tackle.
    Other energy use can be dealt with via none construction based method; efficient appliances , low energy lighting , Solar thermal , PV etc.

    Not sure why the 120 target though ? my flat averages 90 , and its just a basic 1950s masonette with cavity fill and some loft insulation and CFL/LED bulbs. Perhaps its for commercial properties ?
    The AECB gold target of 15 kWh/m2 yr for space heating 58 kWh/m2 yr for all primary energy usage is more understandable .
  27.  
    Posted By: jamesingramNot sure why the 120 target though ? my flat averages 90
    This is primary energy - so if you're using electricity, then the amount delivered to you is approximately 1/3 of this value as the other 2/3 is wasted at the fossil-fuel burning powerstation etc. Of course, since the quota for space heating is rather low, you can't just use gas and still come in at 120kWh/m2/yr.

    Paul in Montreal.
  28.  
    Bear in mind that the Primary Energy target also includes the heating requirement, so if you're heating is all direct resistance then your heating energy could be over a third of the primary energy usage.

    However, this still leaves a substantial amount of primary energy for other uses (lighting, MVHR fans, fridges, freezers, washing machines etc.). Once these are all scaled up to primary energy they use a surprising amount. However, the PassivHaus Primary Energy target is still too easy to hit and should really be lower.
    •  
      CommentAuthorSteamyTea
    • CommentTimeMay 16th 2011
     
    Found some more data that covers earlier in the year
    Chart shows Night and Day electric usage (E7) and temperature.
      Energy Use.jpg
  30.  
    "However, the PassivHaus Primary Energy target is still too easy to hit and should really be lower. "

    that was my thought also, why so high ?

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