Putting Passive House to the test! Pt. 8 - Thinking like the Mini B

The Mini B is a testament to an architect who took the challenge of designing and building a small Passive House and made it look easy.  Of course Joe Giampietro will tell you it took a lot of effort, but the end results were certainly worth it.

Joe attended the Passive House Consultants Training with me and was designing his backyard Mini Bungalow at that time.  He wanted to design something that could be used as an Accessory Dwelling or infill housing in Seattle.  He also wanted to show that it could be built by unskilled, but very passionate student builders.  He succeeded on all counts.  Plus it just looks cool!

I got to see the Mini B as it was being constructed, watched them haul it into its temporary home at the Phinney Ridge neighborhood center one cold dark morning, and attended many a meeting of the PHNW event committee there before it was sold and sent to its new home in Clearwater Commons community in Bothell, an intentional ecological community.  It showed us all that small was possible.  You can read about the Mini B at its website: http://www.minibhome.com/ 

I had an opportunity to ask Joe to walk down memory lane and remind me of the things he faced and discovered on his journey through the PHPP.  It comes down to taking advantage of all the little things you can find, like using 5/8 type X GWB instead of a different version because it is denser and would have more mass.   Another thing he did was put to run THERM calcs on all corners and intersections so that he could take advantage of negative thermal bridges.  He knew the south facing windows would give him great solar gain, but overheating in the summer, so having a plan in place to deal with that is crucial.  Of course the idea that a lot more insulation than you would normally need in this area goes without saying!

One thing Joe was able to do with the Mini B was add a layer of concrete on the floor for additional mass.  Somehow I am thinking concrete and travel trailer just don’t belong in the same design.  Since weight is a factor in being able to have a usable travel trailer that doesn’t need a semi tractor to pull it, I think I will have to keep a good eye on the material choices and their weights.  My original design had steel studs that would be lighter than wood studs to save weight, but perhaps the wood could make a difference in the heating since it would hold the heat longer than the steel?  The PHPP could tell me the difference and I could weigh that against the weight savings to see if the trade off is worth it.  I also liked the idea that a certain variety of GWB made a difference – it’s going to come down to a lot of little things if I am going to be able to design the Passive Bunkhouse to meet the Passive House standard.  I’m enjoying the challenge so far! 

As I focus on the design of the Passive Bunkhouse, I have also set up a temporary trailer on the property that I have been staying in.  This trailer is FAR from Passive House with its single pane jalousie windows that make for a wonderful view of the lake and property, but will mean Linda turns into a popsicle in the winter!  Since staying there I am getting design ideas for the Passive Bunkhouse and that will be the focus of the next blog posting. 

Up Next – What Non-Passive House structures can teach us about Passive House.