This is a unique passive house with a distinct “butterfly” roof which has been designed for both PV solar and Thermal solar systems. It is located in the unique “Kankakee Sands” area of black oak savannas and prairies.The vision for the house was threefold: to be net-zero, to be beautiful and comfortable, and to be congruent with the surrounding “black oak” savanna ecosystem.The house was the result of a chance visit to Pembroke township and the “Kankakee Sands” area and the finding of a 10 acre parcel of black oak savanna in 2013.After an 8 month design period working with Jack Muchie, the architect and several other energy consultants, we arrived at the “butterfly roof” design which provided a platform for the solar PV and solar thermal systems. The site allowed for east-west orientation so the home could be designed to be a long and narrow passive house with an active solar system. The house is two-thirds slab on grade with one-third basement.This home includes many green and sustainable features. All of the basement and slab on grade is insulated with four inches of rigid foam (R-20). The slab is exposed and acts as a heat sink for solar gain from the windows. The wall assemblies are a double-wall standard framing assembly with three inches of closed cell foam and nine inches of dense-pack cellulose (+/- R-50).
Additionally, the roof assembly are 14″ trusses with three inches of closed-cell foam and eleven inches of dense-pack cellulose (+/-R-60). The heating source is only the radiant heat system in the concrete floor which is heated by an electric hybrid hot water heater which is interconnected with the solar thermal system. The solar PV system is a 3.6KW system and the solar thermal system has 8 panels. The windows in the house are triple-glazed windows with a U factor of 0.125. Eighty percent of the windows are on the south side with no windows on the east and west side and small number of the north side for light. The home also features an ERV system. The traditional stucco system on the exterior was chosen for its durability.
The owners are in the process of living in the house and adjusting their energy use and systems to reach “net-zero” status. In 2016, their energy bills totaled $330 for the entire year.