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Another Seattle Passive House – Another Passive House Blog by me!

Announcing the Mini-B Passive House!  Mini-B stands for Mini Bungalow and was designed by Joe Giampietro, a fellow Certified Passive House Consultant.  Joe is an Architect and he took on an impressive Passive House challenge – a small structure.  Passive House uses a lot of modeling, some of which compares the volume of the house to the footprint area it takes up to determine energy usage.  The smaller the structure, the tougher the challenge.  I am happy to report that the Mini-B  has passed the blower door test with a .58ACH @ 50 Pascal and has been pre-certified by Passive House US.

Why such a small structure you may ask.  Joe planned the Mini-B to meet the Detached Accessory Dwelling Unit requirements that the city of Seattle has developed for placing an accessory dwelling on properties within the city.  More than just a fancy backyard office (though it certainly could work for that purpose!) the Mini-B is designed to be lived in.  What used to be called a “Mother-in-law” cottage, this Passive House could be used as a rental, guest cottage, office, man-cave, home away from home but not too far away from home, or just about anything you could put your mind to.

The Mini-B is plumbed to have a shower and a kitchen.  A small living area on the main floor is supplemented with 2 small loft areas above.  Obviously the intent is for  a limited amount of people, but what a great way to provide additional income for someone, or have family close by but not underfoot.

Designed with all the Passive House features, this low energy, high comfort structure will perform to Passive House standards in a sunny southern location as designed, but could be designed to fit the solar requirements of other locations.  Obviously a very shaded lot could exceed the Passive House limits for such a small structure, but the modeling before hand would assist with making it the most energy-efficient structure possible for that location.  Joe said the Mini-B could even be designed to work over a garage, though existing garages would need to be examined to see if they could support an addition.  A likely change would be to build a new garage under the Mini-B in those instances where the existing structure was not strong enough.

Joe is so passionate about this project that someone involved with it has even referred to the house as the Passion House because of the zeal and interest it has generated.  Joe was quick to point out it was not a “Love Shack”, but… 😉 So… where can you get more information and see more pictures of this Passive House marvel?  At my newest blog!  So far I just have Joe’s project listed and a link back to here for Dan’s project.  I will be updating the blog with a project page for Dan’s project real soon now.  If any other Passive House projects would like to be included on the new blog, you can contact me for additional information ( ).

Click on the link to see the new blog, check out the Mini-B, and sign up to receive updates as new projects are entered.  I won’t be following projects on that blog like I have Dan’s, but I will have plenty of “Passive House nerd info” available.  Please give me feedback on additional information you would like to see there!

Visit the new blog!  http://passivehouseprojects.US/


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Seattle Passive House – Chasing the wind…

Dan is actively sealing his house as well as getting past a few more milestones.  Most of the stairs are in, the ventilation system is being piped in and sealed.  Stu returned to make another appearance and Dan put him to work.  Dan has sealed the doorway between the workshop and the utility room with OSB and tape.  He installed a fan in the door and is using that to pressurize the house so he can go around and look for leaks.  He will be gluing and taping the areas he finds and another official blower door test will be run.  Dan has also promised a first hand report of his experience with the air tight sealing methods when he can get time to turn around twice.

A very interesting air leak showed up during the testing.  In the ADU Dan has installed wooden beams.  Because the structure changes at that point from the Larsen Trusses that had the structural support on the front cord to 2X walls with the support on the outside, the beams had to pass through the air tight layer of OSB.  Dan sealed around each beam, but when the building was pressurized he discovered that splits in the wood acted like an Air Super Highway.  He said you could just feel the wind racing through the cracks.  He plans to fill the cracks with putty and sand them down since the beams are going to be left exposed.  Stay tuned!  -Linda

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Seattle Passive House – Measure twice, cut once. Measure once, blower door twice?

I left you with quite a cliffhanger regarding Dan’s project and the blower door test.  I thought I would explain a bit about the Passive House concepts that are affecting the results.  Passive House projects are measured in a variety of ways. 

For determining the Annual Heat Demand, the Gross Enclosed Volume of the building is used – that is the area enclosed by the  extreme outside of the thermal envelope.  In this cross-section of one part of Dan’s project the Gross Enclosed Volume is represented by a dashed blue line.  The yellow represents the insulation in the walls and under the slab.  The red line is the OSB and top of the slab that create the air tight layer.

For Ventilation purposes, the Net enclosed Volume of the building is used.  This is where the question of the project passing the blower door test got a little sideways.  In America, pressurization tests use different volume measurements normally and a number equivalent to the volume enclosed by the air tight layer (including interior walls and floors) was calculated.

For Passive House purposes a more conservative number is to be used for the Net Enclosed Volume.  Basically  it is the empty area that is ventilated within the thermal envelope.  For this project that is all the blank space within the red air tight layer EXCEPT for the bright green area that makes up the floor and interior walls.  The argument can be made that these constructions are not built air tight and will become pressurized and ventilated, but Passive House measurements are conservative and these volumes are not included in the Net Enclosed Volume.

Dan will be crunching the numbers, air sealing some more with the wonderful tape that Siga sent for the project, and trying again to keep under the .6ACH @ 50 pascal requirement that certified Passive House projects must reach.  He is very determined to do so.  He allowed for this scenario when he planned the blower door test.  His air tight layer is still accessible and he does have the opportunity to go back and make changes easily.  When planning your Passive House project, make sure you plan ahead so that you too can tighten the air tight layer if necessary without a lot of fuss.

Dan has really done a remarkable job with his project and I for one am learning so much from following it and presenting it to you on this blog.  Thanks for following along!


[updated to clarify interior wall and floor volume are not included in the Net Enclosed Volume.]

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Existing Resources – Happy 234th Birthday USA!

I love the concept of Existing Resources. Take what you have and preserve it or adapt it. Given enough thought a new life for an old something can create an even newer concept. In communications we have gone from word of mouth and town criers to the internet and bloggers. It’s still passing on ideas and news, just differently. In the world of building we have gone from building with new materials to restoring old places, to dismantling them to become something else. Now we are looking carefully at the cost that building has to the world at large and trying to make a sustainable change for the better and one way we share those ideas is visually through the internet.

For 234 years this country has been adapting and changing, examining what is important and searching to make a better way that benefits its citizens while considering its position in the world at large. It’s not always been easy since we declared our independence, but the one thing that we have relied on as a country is that our Constitution and its’ Bill of Rights has granted us rights that we hold dear.  The world can watch us debate and disagree and stand up for each others’ right to do so.  What an enduring resource our founding fathers left for us.  Happy Birthday USA!

The “Stars and Stripes Forever” march, written in 1896 by John Phillip Sousa is an Existing Resource that has been adapted to create a new visual concept to be presented on the internet.  The different instruments are represented by different colored lines and the length of the notes is represented by the length of the bars.  Enjoy!


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Seattle Passive House – The Blower Door huffed and it puffed…

…but did Dan’s house reach 0.6ACH @ 50 pascal?  The answer is a resounding “maybe”.  Between needing a smaller cowl for the blower door (a temporary cardboard one was crafted) and a question of volume it was most likely between 0.5 and 0.7ACH & 50 pascal – definitely in the ballpark.

Dan was really impressed with the Siga tape – thank you Siga!  Albert Rooks of the Small Planet Workshop will be a US distributor for it in the future.

I will post an update with details as they are available.

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