[GSBN] Embodied/embedded energy figures

[Tom Woolley]

Dear Derek and everyone

As I see it Passiv Haus presents one of the biggest challenges to the  
Natural Building movement for many years
In the Uk , the AECB (http://www.aecb.net)  used to be a good advocate  
for low impact building but now it has sold its soul to Passiv Haus  
and seems to have reverted to the "Only energy in use argument"
There are of course a number of passiv haus projects that have used  
low embodied energy materials ( particularly in Austria) but most do not
I have challenged the leading figures of the Passiv Haus movement face  
to face to justify why they exclude considerations of embodied energy  
but their answer is to say that you can meet their standards with  
natural materials. So why not advocate the use of natural materials  
then?
Many of the Passiv haus approved windows are made from uPVC

I think it is very hard to justify a dependence on mechanical  
ventilation to get fresh air into buildings.
The achilles heel of MVHR systems is changing the filters

Fundamentally passiv haus presents a philosophy that buildings can  
only be low energy if they use expensive high tech equipment
In the UK and Ireland a passiv haus costs between 50 and 100% more  
than a conventional low energy house

Personally I prefer the Walter Segal philosophy of putting on another  
jumper rather than sealing myself up with a lot of plastic and toxic  
materials.

I will be in Darmstadt in November and am considering mounting a  
picket of the Passiv Haus HQ  for an hour or two
Anyone want to join me??

Tom


On 19 Oct 2011, at 02:25, Derek Roff wrote:

> On Oct 18, 2011, at 4:46 PM, Graeme North wrote:
>
>> I also question (and here I risk swearing in church) the whole  
>> philosophy of tightly sealed "passiv haus"  which are then  
>> mechanically ventilated.   The energy intensive approach this  
>> embodies is also up there at the doubtful end of the spectrum it  
>> seems to me. Great until the power goes out.
>
>
> As John Straube has delineated in a number of places, the "passiv  
> haus" standards for air sealing are neither science based, nor  
> completely in harmony with other passiv haus goals.  That being  
> said, this doesn't eliminate the value of mechanical ventilation in  
> many climates and situations.  It should be a net energy-saving  
> feature, rather than an energy consuming one.
>
> Derek Roff
> derek at unm.edu
>
>
>
>
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Tom Woolley

Rachel Bevan Architects
80 Church Road
Crossgar
Downpatrick
BT30 9HR
tom.woolley at btconnect.com
028 44 830988
www.bevanarchitects.com



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