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  • #31833
    Geoff Stow
    Participant

    I often hear people say they are going to have a small stove in their passivhaus for very cold days. But I was told on the course last week that you cannot put a wood burnng stove in a Passivhaus without either not complying with building regs or Passivhaus certification. This was all to do with providing the stove with enough air. Room sealed stoves are not approved under building regs at the moment. Is this a fair comment summary of the situation.

    #39029
    Alan Clarke
    Participant

    What course was that then?
    I don't see why room sealed stoves don't meet the regs – the relevant requirement is J1″Combustion appliances shall be so installed that there is an adequate supply of air to them for combustion…” – a correctly specified external air duct to a room sealed wood burning stove would satisfy this requirement.
    If you look at section 2, Air supply to solid fuel appliances, 2.1 says “A way of meeting the requirement would be to adopt…the guidance below” As the following table doesn't have an entry for room-sealed stoves I'd say you're looking in the wrong place to find the relevant guidance and should use the stove manufacturer's recommendations.

    That said, there are serious risks in connecting a standard-ish stove (which doesn't meet German room air independent spec of airtightness, say) to an external air supply when there is a risk of the ventilation system depressurising the house, ie without differential pressure monitoring interlocked to the vent system.

    #39030
    Geoff Stow
    Participant

    This seems to be the reasoning.

    pg29 Table1 of ADJ
    Air supply to solid fuel appliances – Other appliance, such as a stove, cooker or boiler, with no flue draught stabiliser – If design air permeability <= 5.0m^3/(h.m^2) then 550mm^2 per kW of appliance rated output, of permanently open vent

    I can't quote what the passive house rules are, but I susspect they are designed to have a air permeability of less than 5.0m^3/(h.m^2), and having 550mm^2 per kW of appliance rated output of open vent in the wall would not be allowed. This is the approved way of complying with the requirement under the building regulation to provide sufficient air supply to the appliance. You can install a appliance with a diect air supply as the only source of combustion air, but it is then upon you to prove that the installation complies with building regulations.

    HETAS have recently finished a detailed study into this, and although not published yet, the verdict I have heard is that simply fitting a direct air kit does not guarantee compliance, there are a number of factors affecting if it will or not. The final report from this is as far as I know yet to be published, but once it is will hopefully feed into future regulations allowing certain appliances under certain conditions to be fitted without the permanently open air vents. Currently though, if you want to install the appliance under ADJ, I don't think you can comply with it and the passive house code.

    #39031
    Anonymous
    Inactive

    Hi Geoff/Alan,

    Are you aware of any update on this please? ADJ doesn't appear to have changed.

    Cheers,

    Andy

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