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icf build

  • 18-11-2012 11:08pm
    #1
    ivorfa
    Registered Users, Registered Users 2 Posts: 43 ✭


    Is it worth the extra money to add extra insulation eg insulated plasterboard to reduce the u value of the walls on an icf build house, the u value of the icf walls are 0.20 any advice would be appreciated.


Comments

  • #2
    [Deleted User]
    Posts: 31,118 ✭✭✭✭ [Deleted User]


    It depends on just how high you believe fuel prices* are going to be in the future, I built with an ICF system that had a stated value of 0.19, I did think about adding to it but just couldn't stretch the budget.

    If you do go for extra, it's better on the outside as you can use the mass concrete as a thermal store for the interior of the house. Stick some extra in the loft & floor as well.

    *oil prices are already at a level that crush economic growth, Personally I don't expect them to rise too much more, maybe one more doubling in the next ten years (they've doubled since I built).


  • #3
    windyboy
    Registered Users, Registered Users 2 Posts: 90 ✭✭windyboy


    Hi,

    I built a 2 storey detached ICF house on an exposed site in NW (Irish system), floor area approx 270m2 with wall U-value 0.2. We moved in Sept 2011. We have UF heating on both floors and all of our hot water supplied by a Nibe 1245 heat pump with horizontal ground collector. Windows (78m2) are triple glaze 0.9 U-value. We have a warm roof construction with 225mm deep cellulose pumped between rafters giving a U-Value of 0.2. Rising walls are also ICF. Ground floor 275mm silver EPS giving U-value 0.14. Heat recovery ventilation (90% efficiency). I believe the blower door test achieved 1.5 ACH @50 Pa.

    The Final BER rating is A2 @ 49.06kWh/m2/yr.

    The house is more or less constant 21 deg C. I started monitoring the consumption of the heat pump (using owl energy meter) this year on 31st Aug 2012. Since then it has consumed 938 kW/hrs, = €121.16 giving an average daily cost over that period of €1.45. Looking at yesterday's running cost it was €1.86 (we have dual tariff meter, note these costs are ex VAT and not including standing charge).

    My aim was to build a low energy house with passive house principles, to answer your question we did not feel the need to add any insulated plasterboard and I am extremely pleased with the outcome and comfort level in the house.

    My advice would be to get a good consultant familiar with Low energy/ passive design to assist you in your decision making for building fabric, thermal bridge details, heating system specification etc.

    Regards,
    windy boy


  • #4
    sas
    Registered Users, Registered Users 2 Posts: 1,282 ✭✭✭sas


    windyboy wrote: »
    The house is more or less constant 21 deg C. I started monitoring the consumption of the heat pump (using owl energy meter) this year on 31st Aug 2012. Since then it has consumed 938 kW/hrs, = €121.16 giving an average daily cost over that period of €1.45. Looking at yesterday's running cost it was €1.86 (we have dual tariff meter, note these costs are ex VAT and not including standing charge).

    My aim was to build a low energy house with passive house principles

    This is a fabulour result on your running costs. You must be thrilled.


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