
HPH098 : An Off-Grid, Earth-Sheltered Passivhaus– with Christina Snyder (Passive House)
Architect, builder and Passivhaus Consultant, Christina Snyder shares the story of the experimental zero-energy Passivhaus self-build that she and her husband have undertaken in Michigan, and explains why they are in no rush to complete it.
Interview with Christina Snyder
While this is Christina's first self-build, she has been involved in projects since childhood when she helped her father to make solar renovations on the family home. In high school she won a design competition for a solar house and, after graduation, began teaching students how to design zero-energy homes. After being beaten in a competition by a team specialising in Passivhaus, she decided to do the training and become a Passivhaus consultant.

Photo by Jim Deigart
The House is on the ‘Bleeding' Edge of Technology!
The project is innovative and experimental in the features that it is bringing together into a single house:
- It will be both Passivhaus and zero-energy
- It will be powered with a nickel-iron battery system
- It will use solar and wind power
- The surplus energy from the solar hot water system in the summer will be stored to provide domestic hot water and heating through radiant floors in the winter
- There will be a composting toilet
- There will be grey water and rainwater storage
4 Years In, and Possibly Another 16 Remaining!
With so many experimental ideas it is not something they would have wanted to try out on a client house. Christina and her husband however are happy to throw all the ideas together and take their time, possibly even over a couple of decades, to complete the house. They aim to do the project in phases with results being tweaked as they go.
Good Solar Exposure was Fundamental to Finding the Right Plot
Requiring sunshine from 9am to 3pm all year round in order for their energy needs to be met meant that they used satellite images and solar pathfinders to help locate suitable plots. Benefiting from the economic downturn they were able to source a rural plot from a farmer.
Progress of the Build so Far
The house has 3 storeys on the south elevation and 2 on the north, one of which is below ground level. Retaining the hole which was 14 feet below ground level on the north, and 3 feet below on the south, was particularly challenging throughout a very wet year.
The construction below ground level uses 16inch thick structural insulated panels made from EPS beadboard and coated with glass fibre reinforced concrete. This is also the weather barrier, and on the inside acts as the air barrier. They selected this method as it provided the insulation levels required, would give the necessary strength and had less CO2 emissions than insulated concrete forms would have had. Spraying the concrete onto the Styrofoam walls was a gruelling process that needed several hours continuous spraying at a time to ensure the concrete didn't set in the hose.

Cleaning up after the first spraying of GFRC over the 12” insulated EPS foam floor with red radiant floor PEX tubing over the continuous structural basement foundation slab.
Being largely self-taught, this method took a lot of experimentation and they're still not in a position where they would use it on a client's house.
The wooden walls, made of I-joists, have been erected and filled with cellulose insulation, the roof is in place and all but 2 windows have been fitted.

A mock-up of the 2×4 wall framing on the interior of the plywood air barrier (which has grey tape sealing cracks and fastener holes) shows how the electrical wiring can run in the thermal break in the wood sill plate to get by the picture window.
The build has been ongoing since 2011 and they hope to move in in around a year.
Root Cellars Will Provide the Right Climate for Different Food Types
There will be a total of 3 rooms that will each have different combinations of temperature and humidity to ensure that different foods are kept in the right conditions. Being below the frost line they should remain cool all year round.
The challenges of the build have been testing on their relationship at times but Christina is confident they've got what it takes to see things through.
Find Out More
Find out more about Michigan's first earth-sheltered Passivhaus
Christina is Principal of Equilibrium Energy Spaces and member of CertiPHIers Cooperative
Transcript
Download a transcript of the interview with Christina Snyder
Watch the Videos from Self Build Live
Potton is currently building a new Passivhaus show home. And they are welcoming visitors to site near St Neots, UK, as part of Self Build Live.
However, if you're too far afield you can keep up with the progress on their blog as well as watch videos every step of the way.
Video produced by Regen Media
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About The Author
Lucy Cowell is owner of the Virtual Assistant company Quantum PA. Being immersed in the world of architecture for over 20 years and since working with Ben Adam-Smith, she is now determined to build her own house one day too!