[GSBN] Straw-Bale Blower Door and Infrared Test Results

[David Arkin, AIA]

Hi Dan, David E.:

Sierra Energy Professionals (SEP) say:
> When the house pressure was at a 50 Pa difference relative to the exterior, the flow of
> air infiltrating from outside into the building envelope was measured to be 617 cubic
> feet per minute (CFM).

Based on "9592 cf house", 617 CFM = 37,020 CF/hour, or 3.8 times the volume of the house:

Flow @ 50 Pa	Air changes per hour (ACH) @ 50 Pa
617 CFM		3.8

If the house were tighter:
160 CFM		1.0 (probably about what John's house is)
96 CFM 			0.6 (Passive House (PH) certification threshold)

So house is 6.4x leakier than PH threshold.  We've done a passive house project since this one, but none bale ... yet. 

However, this is an off-grid home, with a combined passive and active hot water heating system, storing heat in an insulated sand bed, with electricity from a photovoltaic system.  So we're wasting some of that free energy from the sun ... I think we can live with that!

John, it's our 'typical' system of 14" I-joists at 7' to 10' on center, with 3-string rice bales on edge, PISE finish.  

More cheer to y'all,

David A.

On Dec 23, 2010, at 9:42 PM, Dan Smith wrote:

> David and Anni, thanks for sharing this, it is a treat.
> 
> What's the air change per hour at 50 Pa?
> 
> Happy Holidays,
> Dan
> .......................................................
> Dan Smith
> Principal - DSA Architects
> 1107 Virginia St.
> Berkeley, CA 94702
> 510.526.1935 x101
> 510.526.1961 fax
> dan at dsaarch.com
> www.dsaarch.com
> 
> On Dec 23, 2010, at 2:48 PM, David Arkin, AIA wrote:
> 
> Hello Fello Baleos Worldwide:
> 
> Since this list is particularly alive today, I'm taking the opportunity to share a Christmas treat.
> 
> I attach here (gosh, can I attach to this list?) a report on a Blower Door and Infrared Camera test done on a 900 sq. ft. (85 sq. meter) home in the foothills of the Sierra Nevada mountains.
> 
> In particular, dig this quote from Michael Ukraine of Sierra Energy Professionals:  "Any doubts that I had about straw bale or SIP construction are thouroughly gone after conducting these tests.  This is definitely the tightest and best insulated house I have ever tested."
> 
> The photos are quite illustrative, but certainly say that the bale walls in no way constitute a weak link in a tight or thermally superior building.  Don't ever let anyone try to tell you otherwise.  We raise a glass to y'all, and wish you an excellent New Year!
> 
> David and Anni
> 
> 
> <Straw Bale House Photos 2010-10-18.pdf>
> *  *  *  *  *


*  *  *  *  *
Arkin Tilt Architects
Ecological Planning & Design

David Arkin, AIA, Architect
LEED Accredited Professional
CA #C22459/NV #5030

1101 8th St. #180, Berkeley, CA  94710
510/528-9830
www.arkintilt.com

"There is no way to peace. Peace is the way."
— A. J. Muste 






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