Grieser ADU

...(Oct 19^th is the 10 year anniversary of Elemental Energy!), I also wanted somewhere to finally put all my solar equipment and somewhere to call home.

After living off-grid on the property in a solar-powered travel trailer, I started construction of this home (ADU*) in the summer of 2019. I wanted to build a home to match the characteristics of the Cully neighborhood – a self-sufficient country house in the city. So I began the design, and modeled the home after my grandfather’s Swedish countryside home.

I wanted to build a house that was 100% solar-powered, off-grid capable, with a hot tub.

100% solar-powered, as in an all-electric house – no natural gas or other fossil fuels used onsite, and all that electricity was provided onsite.

Off-grid capable, as in the house could operate autonomously, indefinitely without the grid. To achieve this, it means oversizing the solar array, so that not only do I achieve total annual offset, but also full offset during the darkest months of the year. In December or January, my house, and its energy efficient footprint, could stay in operation via its own rooftop solar generation, even when the average peak sun hour a day is 1.0. This means 10kW of PV on a 571 sq foot home and two Tesla Powerwalls with a combined usable storage capacity of 27kWh.

With a hot tub, I wanted to show that yes, in Portland, and that yes, via solar power, you too could live off-grid in a home with energy luxuries such as a hot tub and completely offset that usage on or off-grid.

While the solar and energy storage system are the main features of the home, achieving those goals were made much easier, and with a much more comfortable living experience, through some basic energy efficiency measures.

Heat and air conditioning is provided primarily via a 1-ton ductless mini-split heat pump. Additionally, the concrete slab floors are heated and cooled via an electric hot water heater-powered hydronic floor system. The slab and surrounding foundation are insulated with 4” of rigid foam. There are provisions in place for a wood burning stove, if in the future I decide to add one.

All walls were framed with 2x6 studs, spaced 24” on center, and advanced framing practices where convenient (window and door alignment). The ceiling has 2x12 rafters insulated with 3” of closed cell foam. The remainder of the cavity and all walls are insulated with dense pack blown in insulation.

*ADU – This home is intended to eventually become an ADU. The project was constructed on a vacant lot, and this home is designed and situated in accordance to zoning rules for both an ADU and a primary dwelling unit. In the not-too-distant-future, design and construction work on the primary dwelling unit (i.e., the main house) will begin, and this smaller home will be reclassified as an ADU.