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Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
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    • CommentAuthorjules
    • CommentTimeMar 2nd 2010
     
    We're shortly to receive our first serious gas bill (heating and HW) in this house since we refurbished it. I've nothing to compare it with, but obviously I'll be able to work out how many kWh/day we've been using over the winter. Question is, how will I know whether that number is good or bad?

    Does anybody have a source of data, or even their own, which indicates the typical range of heating/HW requirements for an average house, preferably in kWh/day or year/square metre floor space or cubic metre volume? I'm sure such figures already exist on this forum somewhere, but it ain't easy to find!

    Thanks
    • CommentAuthorseanie
    • CommentTimeMar 2nd 2010
     
    Sutherland tables give the following for Scotland;

    Terraced 2 bed house; 11,100kWh space heating & 2,000 kWh HW per year
    Semi-detached 3 bed house; 15,200kWh space heating & 2,500 kWh HW per year
    Detached 4 bed house; 23,300kWh space heating & 3,000 kWh HW per year
    • CommentAuthorjules
    • CommentTimeMar 3rd 2010
     
    Thanks for those figures. I don't know what floor area a Scottish 4-bed detached house is deemed to have, and of course one has to estimate what proportion of that annual total for space heating is used in the winter 3 months. I am interested if anyone has some figures for their own home, ideally in kW/h per day over the last 3 months - with floor area quoted to enable a comparison.

    My gas bill is now in, and my average since the end of Nov is 172kWh/day, but that's for about 240 sqm - and a long thin house as well. We do have solar thermal, but that won't have done much.
    • CommentAuthorNickiB
    • CommentTimeMar 3rd 2010
     
    Hi Jules

    I heat with wood and don't have gas : I use 3.5 kWh per day of electricity for everything apart for hot water and heating - for 68 m 2 for one person if that is any use. I think my daily average is down to about 3 per day since my oven broke. (I still have my induction hob to cook on)

    Nicki
    • CommentAuthorCWatters
    • CommentTimeMar 3rd 2010
     
    Posted By: jules My gas bill is now in, and my average since the end of Nov is 172kWh/day, but that's for about 240 sqm.


    So about 0.71 kWh/day/m^2 in winter. About the same as me in winter I think

    Averaged over a year I'm using around 0.32 kWh/day/m^2 for heat and H/W. Area 330sqm & family of 4. House built to Building regs 4 years ago but no more.
    • CommentAuthorseanie
    • CommentTimeMar 3rd 2010
     
    The figures I gave were for effective output so the actual consumption would be higher.

    I've seen figures from one of the utilities that the average household's annual gas use is around 20,500 kWh and electricity 3,300 kWh, although I don't know what the 'average household' constitutes.
    • CommentAuthorwellanna
    • CommentTimeMar 3rd 2010 edited
     
    Nationwide has some interesting published material on house prices which also includes floor area data for various house types. See:

    Semi-detached: http://www.nationwide.co.uk/hpi/historical/SD_Houses.pdf
    Detached: http://www.nationwide.co.uk/hpi/historical/D_Houses.pdf
    Terraced: http://www.nationwide.co.uk/hpi/historical/T_Houses.pdf

    Sadly they don't include any energy usage figures :sad:

    Neal.
    • CommentAuthorCWatters
    • CommentTimeMar 3rd 2010 edited
     
    Google found this..

    http://www.unece.org/press/pr2008/08env_p13e.htm

    It's talking about Geneva but says..

    Low-energy buildings have brought average energy consumption per square metre (m2) per year to less than 50 kilowatts (kW), as compared to 150 to 200 m2 in “normal” housing.


    I assume they mean kWh not kW.

    50kWh/m^2/year = 0.13 kWh/m^2/day
    150kWh/m^2/year = 0.41 kWh/m^2/day
    • CommentAuthorjules
    • CommentTimeMar 3rd 2010
     
    Most published data not unreasonably gives annual figures, which makes comparing with winter numbers - especially this winter - difficult. If I'm on a par with CWatters it sounds as if i shouldn't be too unhappy: our house is 3 100-year-old buildings tied together, long and thin so a large external surface area, and a lounge and master bedroom with 3 outside walls.
    • CommentAuthorsinnerboy
    • CommentTimeMar 3rd 2010
     
    SEI publish monthly stats on BER ( EPC) certs issued

    http://www.sei.ie/Your_Building/BER/BER_FAQ/FAQ_BER/Assessors/January_Status_Report.pdf

    That way you can put a buildings rating into some context

    Is there such data available in the UK ?
  1.  
    I use 60 - 70kWh per day for CH and DHW for a detached property of 220m2 over the winter period.
    • CommentAuthorjamesingram
    • CommentTimeMar 6th 2010 edited
     
    workaholic - Do you know your kWh/year/m2 for total energy use , be interested after reading your description on the other thread.
  2.  
    James
    We have only been back living in the property since August. We had to move out for the major work. The heating has only been up and running since October so I have yet to get a full year in.
    •  
      CommentAuthorDamonHD
    • CommentTimeMar 7th 2010 edited
     
    For our family of 4 in 2/3 bed end-of-terrace in London 'burbs (76m^2 heated floor space), 2MWh/y electricity, 6.2MWh/y gas (CH+DHW) for 2009:

    http://www.earth.org.uk/saving-electricity.html#meter2009

    Until last year gas was about 9MWh/y and until about 3 years ago electricity was about 10MWh/y. Smug, moi? B^>

    AFAIK, modal electricity consumption in UK is ~3.3MWh/y, mean 4.7MWh/y (presumably reflecting houses inefficiently heated by electricity), and gas 18MWh/y. I believe that all but about 1.5m of the 26.5m UK households are on (or have access to) the gas main.

    The source of all these figures is the excellent UK government's DUKES (Digest of UK Energy Statistics), available at a browser very near you:

    http://www.decc.gov.uk/en/content/cms/statistics/publications/dukes/dukes.aspx

    Rgds

    Damon
  3.  
    Just done my Heat loss calcs and have a full year of gas use.

    200m2 1920's Semi. Fairly well doubleglazed/sealed/insulated.

    Fabric and Vent Heat loss approx 5.5 kW (@-3C external - 20C internal)
    2kw for DHW =
    7.5 kWh peak load.

    Total kWh for March 09 - March 10 = 13873

    Reckon about 500 of that is Cooking.
    Heating is off for 5 months over the summer. Estimate about 500kWh a month for DHW.

    Started taking gas meter readings every month.
    Oct-09 853
    Nov-09 1516
    Dec-09 2591
    Jan-10 2597
    Feb-10 2249

    reckon the heating went on half way through October.

    Looking forward to seeing how this pans out over the years.
  4.  
    It depends where you are. I'm in the SE of England (London SUburbs) and my house is a 5/6 bed detached with converted loft. About 240m2. Built 1926. Double glased, cavity wall insulated, good roof insulation, condensing boiler. I have been using an average of about 80kWh/day gas since November. I hope this helps. 172kWh/day sounds quite high.
    • CommentAuthorwookey
    • CommentTimeMar 8th 2010
     
    Jules - you could sign up to imeasure (http://www.imeasure.org.uk/ ) and compare yourself with some of the groups there. Might help you place yourself.
    • CommentAuthorjules
    • CommentTimeMar 8th 2010
     
    Thanks for interesting comments. It makes you realise how many variables there are. Our house is occupied all day (v young children), so heat is on downstairs about 16 h/day, albeit at a lower temp during the day. I guess that could increase my heating requirements by as much as 50%. We also have UFH in most of downstairs, and I'm still experimenting in how low I can turn it for how long.

    I did start this thread because I was a bit taken aback by the size of my gas bill. dimengineer's usage seems a good target to aim at, but that will be tough, especially since I suspect that a long thin 2-storey house is not as thermally efficient as a box with three floors on top of each other.
    •  
      CommentAuthorDamonHD
    • CommentTimeMar 9th 2010
     
    We have young children too, both well under 5, with heating nominally on for a little under 16h/day.

    On imeasure we get an "A" rating compared to the general user base, but only "B" against families with children in similar properties, so you could probably come slightly closer to our consumption without too much pain. Our gas bill is well under Ă‚ÂŁ400/y, and expect it to stay that way even on Ecotricity's new Green Gas tariff slightly more expensive than our previous Atlantic deal, since I intend to reduce demand faster than prices go up! B^>

    Rgds

    Damon
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