At the forefront of zero-energy residential living in Oregon, the Westanna project consists of two identical three-storey blocks with 12 units each, achieving net-zero performance through high-performance insulated walls, triple-pane glazing, and a rooftop array of 112 photovoltaic panels. With a 1:1.54 plot ratio and bike-friendly planning, the development demonstrates an urban model for low-carbon, resilient housing.

The energy model to achieve on-site net zero forced the design team to balance the desire for glazing and daylight with the need for a high-performance thermal envelope. Various strategies are implemented to achieve this: eliminating the elevator shaft to reduce energy load, integrating combined heat-pump systems for both water heating and air conditioning, and tightening the building envelope to minimize thermal loss.

Balconies are incorporated into each unit for daylighting, urban gardening, exercise, or rest — supporting post-pandemic expectations for flexible outdoor living. The roof extensions on the patios allow for more area for the solar panels and cover from the Pacific Northwest rain. As an urban infill building, the triple-pane glass and a tight envelope offer residents a quiet break from the street below. This project aims to prove that small-scale net-zero infill housing can be a sustainable option to address housing shortage on the west coast, and how low-carbon construction can work using solar design even in rainy Portland.