Wednesday, February 9, 2011

'Active House' is that better than Passive?

8 Feb '11: I met Julian Marsh, one of my architect friends today, who was visiting the Dept of Arch and Built Environment. He has a self designed house in Nottingham and is the architect of the highly excellent Green St houses in the Meadows. He promotes the idea of the 'Active house' as better than Passive house, a sort of cheerful British interpretation of the slightly joyless German ideal.
    That is more like my house, where you don't have to live in a airtight box, dependent on a fan for breathing. You make sensible use of the PV and a heat pump, open the windows in summer for ventilation, have a sunspace with openable shutters, allow the occupants to make sensible energy saving decisions such as solar shading by day or closing curtains at night. 
    Like me, he has been monitoring his energy figures, to try to get below carbon zero. I will invite him as a speaker to one of our West Bridgford Ecohouses meetings in the future.
    I gather that Julian's house is about as carbon zero as the Peveril house, i.e. is covering the heating, and more than that, but with the 4kW limit on PV panels in the British Feed in tariff, he doesn't have enough PV to cover the entire electrical consumption. With being on a corner site, he has two party walls, so has fewer external wall surfaces to lose heat.
   He does have a small amount of MVHR, but not on the whole house - uses it on the most lived-in zones of the house. This is a pointer to how I could use it - it is too difficult to instal a Whole House system, but I could have an exchange between the Kitchen area and the main Living space. The articles in the links below provide additional information.
  Another my friends, Gil Schalom has a eco-upgraded victorian house in West Bridgford and has zonal MVHR rather than in the whole house.
In 10 March 2011, the Architects Journal devoted a long feature article to Julian's house. (Unfortunately there's a paywall on the AJ website, but if you are a subscriber it is visible)
also visible are these links:


  1. David,

    Many people believe that you can not open a window in a passivhaus - this is simply not true. When the window is open the mvhr turns off i.e. if you want to ventilate through a window be it summer or winter that is your choice. In summer it makes no odds and you lose nothing as the building requires no heat in any case. In the winter however, the purpose of being so air tight is to control the heat loss from the buidling (in a passivhaus the heat requirement is over 80% due to air changes and the rest is due to fabric and very little air leakage)so if you dont control the ventilation you on to a loser. So if you open the window in winter - you take the hit - its your choice.. in summer theres no difference.
    (unless you are trying to actively cool the building, where you would want a sealed box.)

  2. Is there any better explanation of "aktive house"

    Beside passive house i am aware of "plus energy houses "

    Simply means to concentrate on exporting more energy than importing energy

    Your house could do that perhaps , but you are burning your PV production for heating and hot water , so you have to import dirty electricity from the grid

  3. Under the feed in tariff, we are limited to 4 kW of PV.... although we could have more and expect lower payments. I would be prepared to do that, but the inverter we have is not sufficient to add another 2 or 4 PV panels. Our roof generates 3,300 kwh. If I can get the GSHP annual consumption down to 3,800 and deduct about 360kWh used by the floor circulating pump, that gets us to 3440, still above the PV roof generation.
    If we had a woodburning stove, we could considerably reduce the heating load, but this the data from this experiment would be confused.


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