A 600 sq.ft. second floor addition and complete remodel of the 1000 sq.ft. first floor make this 1940s house fit for its next 75 years. The deep energy retrofit was designed for net-positive energy performance, whereby the rooftop solar PV system produces more energy than the household consumes annually. The building systems are all-electric (the old gas line got disconnected), with heat pumps for hot water and space heating, recovery ventilation and induction cooking. Although the solar PV system is only a 5kW array, made to fit neatly onto the 2nd floor roof, the overproduction in the first full year of operation amounted to a about $1000 in credit, as shown in the “My Energy Use” graph. The owner has not yet switched to a plug-in vehicle, but - with nighttime charging - the 2015 credit could have provided for some 20,000 miles of electric driving; once around the globe.
Other than enabling our client to go fossil-fuel and carbon free for their domestic energy needs and mobility, building materials were also chosen carefully with respect to “carbon footprint” and indoor environmental quality. The interior stair and the new fence were built from salvaged wood, repurposing the lumber from the old roof.