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

[John Straube]

I dont think there should be anyone handing out edicts.  This has not worked very well in any of the codes, standards and programs.
In general there tends to a consultative process involving stakeholders, a few meetings etc.
That said, I have no problem with anyone, like Passiv Haus making edicts and have people volunteer to follow them.  Nothing wrong with that.
But claiming there is a defensible scientific basis for numbers that are made up, is damaging and then it bothers the rest of the industry and society.

LEED claiming energy savings and then not delivering on them is bad, not for LEED, but for society that chooses LEED on the belief that the statement was true.

PassivHaus requiring 0.6 ACH at 50 as a voluntary program.  No problem.  But when they claim this number is scientifically based, it distorts, well, science.  When they claim PHPP is more accurate than other programs, when it is not, this distorts the truth. When they say the German window tests are more stringent than NFRC, and they are not, etc etc.
So I am trying to get to the bottom of some of these claims to see where the science is, and where the "I just picked this number" is.

Actually, because most of the PassivHaus standard is plain good low energy buildings, and I love that, I am also hoping that by accomodating different cultures and climates, PH may become something that is a program that could be more widely used, that I could recommend, and hence could really make a difference. I worry that it will hurt other programs, products and approaches if people beleive in it dogmatically.

Hourly programs, off the top of my head
HOT3000, free for the download
EnergyGauge USA
WUFI Plus (expensive, like $5000, but wow)
Sunrel (free)
Energy-10 (very inexpensive, really good for small commercial but houses too)

All of these programs require the input to be correct.  Eg, you have to enter Real R-values for the enclosure, including thermal bridging, and real window U-values, including frames and edges.  This is easy to do, if you know what you are doing.
I also use an hourly Excel program (eg 8760 rows, one for each hour) to do some work on wackier control ideas, and solar overheating, etc



On 2011-01-28, at 11:11 AM, Jeff Martin wrote:

> John,
> 
> I've been following this discussion with great interest and find it very informative. I understand your objection to the seeming inflexibility and arbitrariness of the Passivhaus requirements, but am curious about what rules you would use to define the standard, if you were the one handing out the edicts, instead of the Darmstadt folks. :)
> 
> Also, could you tell us a bit more (name, source, cost, etc.) about the hourly programs that you mention you are using in the design process?
> 
> Thanks... Jeff
> 

Dr John Straube, P.Eng.
Associate Professor
University of Waterloo
Dept of Civil Eng. & School of Architecture
www.buildingscience.com