[Greenbuilding] Aggressively Passive: Building Homes to thePassive House Standard

[jfstraube]

Hi George.  Thanks for your comments!  Appreciate the chance to stretch my brain with this conversation.  Not sure, but I think I will be in the Bay area doing a PG&E thing in April.
You say:
>> 1. 120 kWh/m2/yr of source energy
> This is for your all of your energy at your building site. And using the U.S. DOE average for source energy conversions need to be entered replacing the E.U. #'s. And the appropriate #'s for Canada should also be used.
Where is this documented?  The PHPP spreadsheet and handbook I purchased from the Katrin's PHIUS show 2.7 and I cant find PHIUS documenting anything else.  Are you told these things as part of the secret initiation rites?
I use values of 3.365 for electric, 1.092 for gas and 1.0 for PV as US average values based on the extensive research work by NREL"
"Source Energy and Emission Factors for Energy Use in Buildings
www.nrel.gov/docs/fy07osti/38617.pdf
>> 2. 15 kWh/m2/yr of annual space heating demand
> and 15 kWh/m2/yr for space cooling, this and heating are based on site energy use (as opposed to source energy)

I am pretty sure the value is demand, not consumption.  Energy demand is always site energy by definition since it is demand, energy consumption can be site or source and vary all over the place.
So a better line might have been
2. 15 kWh/m2/yr of space heating and 15 or cooling energy demand.  
I am not clear if this means I can use 30 for space conditioning, or that the cooling should be part of the 15 budget.  

The pressure test is a lot like the ASTM E779 because it was written directly from this standard, and in fact the ASTM standard is a direct copy from CGSB 149.1, the original Canadian standard.  Like a game of telephone, a few things changed but nothing meaningful.
The requirement of 1 Pa is a bit of a joke, as it is rare to find anyone who can actually accurately measure 1 Pa.  The number must have been chosen because it is a round number, as like most PH recommendations I can find no science to support it.  While Feist is much more flexible and reasonable than regional PH bodies, I am surprised to to hear that he says this is a requirement: it is not in the list of requirements in the documents. Katrin insists that an 80% HRV is required (which could save a lot of energy relative to supply or exhaust).  To get the same air quality with a supply or exhaust only system you need to use more airflow.  That is a scientifically proven as well as common sense fact. And/or you need to circulate the air through the home more regularly.  But I digress.
The changing requirements and recommendations and lack of documentation of what is what is maddening to me. The claim is that PH is rigorous, but following the online forums and looking at this myself, it is remarkable imprecise and open to "Fesit told me I should do this" and "Klingenberg say I must have this", etc. Which is not the sign of a mature program.

>> You have to meet 120 kWh/m2/yr site energy regardless of PV.
> Correct, end of sentence
The PHPP handbook and spreadsheet both allow PV to be entered and account for it as 0.7.  I can provide the tab and cell number if you cant find this reference.
The energy thus generated is simply not allow to reduce the 120 number for reasons that numerous online chat groups to to divine, because there is apparently no official and certainly no scientific reasoning behind it.

> You have achieved an equivalent level of performance, an energy efficient house, and that's is what we all should be trying to achieve, no mater what we call it!
This is the root of my concerns.  Here are some of the high level approaches I would take:
Seems to me, the number that matters is source energy per person, not per square meter.  The heating restriction is simply illogical, as it does not matter what it is (from the environments point of view) if the source number is maintained.
The problem with per person measures is that we dont know the number of people.  Most codes use bedrooms + 1 as the number of people.
In Denmark they have moved towards using a formula of the sort:
X kWh + Y kWh/m2.  
Which rewards small houses, and penalized large houses if X is large enough and Y small enough.  Energy Star version 3 will simply penalize people for every square foot over 2200 (the average)
Various countries have different laws for how to measure TFA: the values of X and Y should be modified to result in the same target between countries, reflecting existing real estate and tax law methods of measuring TFA (Canada and US are the same, Germany is unique).
In Sweden, such an approach was suggested, with two different sets of values, one for the colder part of the country (like our Zone 7) and one for the warmer (like our Zone 5/6).

Until PV reaches around 20% of total annual market supply (decades or further in the future and a happy time), the factor for PV should scientifically be 1.0 or 0.97 (to account for some losses).  The value for wood or biomass on site, should be zero, and the value for biomass from off site should be some non-zero value (the 0.2 value in PHPP seems as good as any guess).


John Straube
www.BuildingScience.com



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