The Oaks/Net Zero Neighborhood

The first of its kind in the Portland, Oregon Senior Living marketplace, this neighborhood stands out as the ideal living option for sustainable minded individuals. Rose Villa has partnered with Green Hammer to develop this one of a kind Net Zero energy neighborhood.

The newly planned Net Zero Energy pocket neighborhood will consist of 9 cottage units that will produce as much energy (through the use of solar panels) as they will consume over the course of a year. The residences are organized as triplexes clustered around a central courtyard that features native landscaping, including two heritage oak trees at the heart of the site. Due to the site’s flat topography, each triplex includes two ground floor units and one upper unit served by both a private stair and residential elevator.

Nestled under the oak trees is a community room and outdoor space which serve as a welcoming gathering point for the members of the Rose Villa community.

The building envelope is a critical component to achieving the Net Zero Energy goal. Through an air-tight, well-insulated envelope, the energy loads of the building are greatly reduced which allows for the use of a highly effi cient mechanical system. The Oak Grove triplexes will be conventional, light wood framed construction and include:

  • 4” Slab-on-grade foundation with a vapor barrier and 4” of EPS insulation below to achieve an R-16 fl oor assembly.
  • 2x8 wall assembly with blown fi berglass insulation in the stud cavity and 1-1/2” of EPS exterior insulation to achieve an R-40 wall assembly.
  • Raised-heel, manufactured wood roof trusses with 24” of blown-in fi berglass in the attic space to achieve an R-84 roof assembly.
  • Triple pane, tilt-turn windows with well-insulated frames • An air-tightness goal of 1.0 ACH50

Also critical to the success of a Net Zero Energy neighborhood is durability and longevity. To achieve this, the walls include a ventilated drainage plane (rainscreen) assembly for the siding. As triplexes, both the party wall and party fl oor assemblies will include well-designed sound attenuation. Exterior shading devices on south facing windows will reduce summer glare and overheating.

With a low heating and cooling demand due to the high performance building envelope, each cottage will be served by an individual air-to-air mini-split heat pump. To maintain excellent indoor air quality, each unit will also be provided a Heat Recovery Ventilator (HRV) to supply continuous fresh fi ltered air to bedrooms and living areas while exhausting stale air from the bathrooms and kitchen.</p

Each triplex will be served by a low maintenance and highly effi cient shared central trans-critical (CO2 refrigerant) hot water heat pump. Hot water will be pumped to fi xtures so no time or water is lost waiting for hot water to reach the fi xture. Plumbing fi xtures will be selected in conjunction with Rose Villa for low-fl ow effi ciency and meeting functional needs. A wet-pipe fi re protection system shall be installed throughout each cottage per NFPA 13R.

Each triplex will have one PGE Utility Meter installed on the building’s exterior. For separate utility information per unit, CT cables will be run to the electrical panels. All light fi xtures will be LED or will utilize screw-in LED lamps. Additionally, appliances will be selected for energy effi ciency and function to keep our overall energy demand low.

The fire alarm system will include single station smoke detectors with integral sounders tandem wired within each unit.

With the building envelope measures and high efficiency mechanical systems and lighting, preliminary studies show that the neighborhood is within range of achieving Net Zero Energy performance per solar panel performance estimates. A 60KW solar array is planned to be provided at the roofs of the covered parking and three major south-facing dwelling roof planes.

SCHEDULE A TOUR