This edition of the Phius Project Spotlight Series highlights the Ellie Passivhaus multifamily building in Seattle, Washington.
Our monthly Project Spotlights highlight the cutting-edge work being done by Phius professionals and provide examples of successful design and construction strategies. We feature projects of various sizes, typologies, and climate zones, offering you a peek behind the curtain of each.
Our June Project Spotlight is: Ellie Passivhaus in Seattle, Washington! Ellie Passivhaus was chosen as Honorable Mention in the Low-Rise Multifamily category of the 2023 Phius Passive Projects Design Competition.
Sound West Group had a goal and vision to create a building that would set the stage for the responsible way to develop. Ellie Passivhaus’ landmark location is one block from Climate Pledge Arena, the greenest arena in the world.
As the largest multifamily Phius Certified apartment building in Washington State (as of 2023), Ellie is setting the stage for the responsible way to build and live. This design lowers total energy consumption up to 64% compared to the national average and provides a healthier quality of life to the residents through constant supply of HEPA filtered fresh air. The Ellie Passivhaus project was 39% above the Priority Green requirement for Seattle’s permit process. Solar panels installed on the roof offset the building's energy use by 15%.
Energy savings are achieved through optimization of the building envelope, solar orientation and incorporating a high-performance building envelope, combined with high-performance mechanical systems.
Specific building techniques use centralized Heat Recovery Ventilation (HRV), for fresh air and exhaust, reducing heat losses by recovering the heat from the exhausted air. Post conditioning heating and cooling system, utilizes inline coils in the HRV ductwork system to provide supplementary cooling in the summer and heating in the winter to the south and east facing units. Utilization of high-efficiency Chiltrix heat pump units with a system that monitors average indoor and outdoor temperatures and requires no user input and high efficiency ductless heat pumps for heating and cooling of the west facing units.
The windows used are triple-pane, argon-filled glazing with composite glass spacers, European double seal uPVC frames with low U-values, over-insulated at openings so insulation returns into frames to reduce the thermal bridge effect of the window installation. Photovoltaic panels installed and EV charging ready. Low energy usage allows the building to avoid the need for a transformer vault, offering significant savings to the owner.
The building features central hot water with a recirculation loop. There are thermal breaks at all exterior penetrations, connections, and intersections. Steel attachments from canopies and walkways are attached using Armatherm thermal break material, reducing heat loss from penetrations of highly conductive materials.
Cast-iron storm and waste piping are used within the structure to reduce plumbing noise. The highly air sealed, vapor permeable air barrier achieved 0.3 ACH. The building is air sealed between units to reduce noise and air transfer between units.
Photos by John Gussman, DC Productions