[Greenbuilding] passive haus article

[Alan Abrams]

on the subject of passive house vs pretty good house--I think that to make
this into a conflict is setting up a false dilemma.  At some point, it
would be valuable to derive some rules of thumb for building in a given
climate, to skip the intensive analysis that PH certification entails.  at
the same time, in any given climate, a house is not a house is not a
house...the thermal behavior of a house will vary according to scale,
massing, and exposure.

it goes back to what your objective is.  if it's energy per square foot,
it's got to be detailed thermal analysis.  If it's a more nebulous, "pretty
good practice for whatever I'm building," then it's PGH.  But they are not
mutually exclusive approaches.  PGH could benefit from, say, an
understanding of whether high or low SHG works better on a given exposure,
or whether another inch or two of insulation in the ceiling improves
performance better than in the walls.

Intuition only gets you so far.  At the extreme end of my thoughts is the
notion that, at some point, PGH is a deliberate dumbing down of design.
 But I am trying to shake it.

AA


On Wed, Aug 21, 2013 at 6:38 AM, Alan Abrams <alan at abramsdesignbuild.com>wrote:

> re the GB advisor article:
>
> some people recoil at the notion of large amounts of sub slab insulation,
> but this is about heat loss via conduction, rather than convection loss
> through walls and roofs.  Heat loss to soil is different than heat loss to
> air.
>
> Conversely (assuming you are looking at net heat loss through the building
> envelope), increasing, say wall insulation, to compensate for heat loss
> under a slab, requires more and more complex assemblies.  It also requires
> either expanding the footprint--adding roof area, increasing tax
> assessments, etc--or reducing interior area.  So there can be some
> advantages to dumping some more insulation where it does not have a big
> impact on other building assemblies.
>
> the downside is that there seems to be no reasonable substitute for foam.
>  My present thinking (not yet implemented) is to put the slab on the ground
> where it belongs, and insulate on top of it, and cover with a floating
> floor system.  let point loads penetrate as they must.
>
> -AA
>
>
> On Tue, Aug 20, 2013 at 7:59 PM, Sacie Lambertson <
> sacie.lambertson at gmail.com> wrote:
>
>> If you can open this, herewith an interesting Passive Haus article:
>>
>>
>> http://www.nytimes.com/2013/08/15/garden/the-passive-house-sealed-for-freshness.html?pagewanted=1&hpw
>>
>> juxtaposed against this discussion suggesting as an alternative:
>>
>>
>> http://www.greenbuildingadvisor.com/blogs/dept/guest-blogs/pretty-good-house
>>
>> Sacie
>>
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>
>
> --
> Alan Abrams*
> **certified professional building designer, AIBD
> certified passive house consultant, PHIUS*
> *certified passive house builder, PHIUS**
> *Abrams Design Build LLC
> *sustainable design for intentional living*
> cell     202-437-8583
> alan at abramsdesignbuild.com
> www.abramsdesignbuild.com
>



-- 
Alan Abrams*
**certified professional building designer, AIBD
certified passive house consultant, PHIUS*
*certified passive house builder, PHIUS**
*Abrams Design Build LLC
*sustainable design for intentional living*
cell     202-437-8583
alan at abramsdesignbuild.com
www.abramsdesignbuild.com
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