[Greenbuilding] Passivhaus propaganda

[Topher]

On 12/5/2013 10:04 AM, nick pine wrote:
> john daglish writes:
>
>> Passivhaus standard with little cost penalty if carefully designed.
>
> With little cost penalty compared to what?
To a more conventionally built house of the same design.
>
> Yes, but every actual Passiv building seems to have too much 
> insulation and airtightness and triple-glazed direct gain windows vs 
> air heaters or low-mass sunspaces.
There is no such thing as 'too much' insulation, only insulation which 
costs more than some factor of what it saves.  Same with air-tightness 
only the cost is mostly in meticulousness.  All these things are 
trade-offs not absolutes.

> Is this a prescriptive requirement or a lack of imagination? 
It is not prescriptive requirement (expect for air tightness).  Any 
solution which meets the energy standards is fine.  If you want to call 
that lack of imagination, fine, I rather suspect other motives.

> Jonathan Hines begins by saying the challenge is to build Passiv "at 
> no extra cost," then goes on to say that extra Passiv insulation and 
> airtightness really do cost more, so they simplified the building 
> design to make the total come out the same (as what?) 

The trick is to use savings from  mechanical systems to pay for 
insulation.   But even if it costs more, it doesn't cost more (per 
month) when heating energy is included in the calculation.  The fact 
that it is possible at all, says something (horrible) about our 
currently building methods;  that you can make a vastly better house at 
the same (or nearly the same) cost.

> But the final design still has about 5 shoeboxes with different roof 
> slopes, vs a simple single shoebox. Why not use a single simple 
> shoebox for cost and performance comparison?

Architect.

> And why all the triple-glazed direct gain windows and their overhangs 
> and brises soleils, vs air heaters with natural summertime ventilation 
> instead of shading, in this "physics-based" standard? 

Feel free to build one that way.  I do note however that there aren't a 
lot of (any?) houses built currently based on large air heaters.  
Claiming that Passivhaus is somehow unique for not building that way, 
when no one else does either, seems to miss the point.

>
> Thanks for the offer. I'll think about that. I get up to see Rich Komp 
> and Elliot Coleman once in a while, preferably in summertime. When 
> Norman Saunders and I were at a solar conference at Bates college in 
> February, the outdoor temperature got above 0, which the locals called 
> "unseasonably waham."

Thank You Kindly,

Corwyn / Topher Belknap

-- 
Topher Belknap
Green Fret Consulting
Kermit didn't know the half of it...
http://www.GreenFret.com/
topher at greenfret.com