King County Housing Authority: Cascade Apartments


Cascade Apartments is a subsidized housing development for families, seniors aged 55+ and people with disabilities. The 108 townhome-style apartments within 28 buildings include a total of 256 bedrooms on 8.5 acres in the Kent, Washington area. Built in 1969, the average all-electric 1,000-square-foot two-story homes were long overdue for energy updates which, starting in 2010, came in two phases. Phase 1 began with King County Housing Authority (KCHA) working with local contractors to develop a series of retrofit measures designed to reduce energy use, increase comfort and indoor air quality, attenuate sound, and increase building durability. Then, in Phase 2, through an Energy Performance Contract with Johnson Controls, the units were upgraded with LED lighting, .8 gallon-per-flush toilets, aerators, showerheads, ductless heat pumps, and energy recovery ventilation systems.


The goal of the energy retrofits was to address several deficiencies, such as excessively high utility bills and moisture levels, which directly impacted the financial and physical health of the community members. For Phase 1, KCHA staff conducted energy audits of the units, which included multipoint blower door tests, assessment of existing insulation, and review of moisture-related issues. These audits also included the use of the DOE Building America partners’ tools and software from which a comprehensive set of efficiency measure were developed. By 2016, efficiency and performance improvements in both energy and water technologies provided renewed opportunities to further increase energy savings through lighting and water efficiency upgrades. Several Phase 1 measures were upgraded again.


  • Ductless heat pumps
  • Energy recovery ventilator in each apartment – 66% efficiency



  • Air seal and insulate attic – R-38
  • Dense pack walls and rim joist with cellulose insulation – R-14
  • ENERGY STAR® double- pane, low-e+Ar, vinyl windows – U = 0.30
  • Re-insulate floors – R-30
  • New doors with a solid urethane foam core and thermal break – R-5, U = 0.20



  • Phase 1, 100% CFL bulbs - common area and residential lighting
  • Phase 2, 100% LED bulbs - common area and residential lighting



  • Faucets/aerators and showerheads - Phase 1, 1.6 GPM; Phase 2, .8 GPM
  • Toilets – Phase 1, 1.6 GPF; Phase 2, .8 GPF

Other Benefits

While the installation of a whole-house ventilation system provided a positive benefit to the residents, some were concerned that the continuous operation of the energy recovery ventilators (ERV) would reduce comfort and raise utility bills. However, KCHA staff has noted a significant decrease in indoor air quality complaints from residents since the retrofits first took place, plus overall energy use has decreased. Additionally, KCHA staff educated residents about the operation and benefits of the ERVs, which helped increase understanding and acceptance.

Additionally, since the 2010 baseline year, along with the 18 percent reduction in whole property (KCHA and resident) energy use and a 6 percent ($6,014) reduction in total costs, KCHA-paid water bills have been reduced by an average of 24 percent, or 1.1 million gallons per year.

Image Gallery

Typical building configuration at Cascade Apartments

Typical building configuration at Cascade Apartments

Aerial view of Cascade Apartment complex

Aerial view of Cascade Apartment complex