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SCinIC | Site Visits & Tribe Updates | Nez Perce Housing Authority Site Visit and Design Workshop

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Nez Perce Housing Authority Site Visit and Design Workshop«

June 13, 2012

The east-facing entry vestibules and porches will improve thermal comfort and align with the Nez Perce tradition. An aerial view of the proposed design of NPHA's new construction project of nine duplexes in Lapwai, Idaho. Insulated concrete forms maintain structural integrity and provide energy efficiency. An energy modeling study proposed five packages of energy-efficiency design options for the NPHA project.

Located in north central Idaho, the Nez Perce reservation spans five counties. The city of Lapwai in Nez Perce County is home to the largest number of Nez Perce tribal members. The Nez Perce Housing Authority (NPHA) has built Energy Star®-certified housing units in past construction projects, but NPHA officials are looking for additional ways to lower utility costs and improve resident comfort in future projects. This summer, NPHA will begin construction on nine duplexes (18 two-bedroom units) to house low-income families in Lapwai. NPHA’s Executive Director Laurie Ann Smith requested that the Sustainable Construction in Indian Country (SCinIC) team review the project’s original duplex design and make recommendations that would improve energy efficiency for the project. In April, the SCinIC team visited the Nez Perce Reservation to present findings from the design review process and to conduct a design workshop with NPHA staff and residents.

In preparation for the SCinIC visit with NPHA staff and residents, an energy modeling study was conducted to compare energy use projections of the duplexes’ original design to one that uses a package of alternative sustainable construction measures. The study found that through the use of such measures (including the use of straw bales to improve wall insulation, floor and roof insulation improvements, ductless heat pumps, and a heat pump water heater), the project could achieve energy savings of as much as 60 percent. In the study’s model, various sustainable construction materials were tested, including structural insulated panels, insulating concrete forms, phase change material, and straw bales. The report also proposed a series of five packages of energy efficiency design options to consider for the project’s construction.

During the April visit, the SCinIC team presented findings from the energy modeling study, and discussed the results with NPHA staff and residents at a design workshop. NPHA staff and residents were shown proposed design improvements, which included architectural and site planning alterations to improve the social and cultural aspects of the project. The SCinIC presentation included three-dimensional computer renderings of the proposed housing division. Participants voiced strong support for, and interest in, many of the proposed design improvements. The SCinIC team also proposed a plan to increase the amount of community space in the project by changing the parking layouts and adding carports. The revised design plans also added east-facing entry vestibules and porches that will improve thermal comfort and align with the Nez Perce tradition.

SCinIC team visited AHA July 31 - August 1, 2012. When the team members toured the new units and the training facility, they visited the largest hydropower project in the United States (a joint project with Canada), and collected some additional data.

The comparison multifamily units were built in 1998. They are 2-bedroom, similar in size to the new units, and are in 4-unit, single story buildings. The comparison units employ a typical wood frame construction with siding over Tyvek house wrap over OSB sheathing. The roofs are asphalt shingle with R-38 insulation above the ceiling. The slab foundations are insulated and windows are double-pane glass in vinyl frames. The units are kerosene oil heated and cooled with individual window units; buildings include electric water heaters. Units did not yet have ENERGY STAR® rated appliances, but did incorporate compact fluorescent lighting.

According to SCinIC’s energy analysis, in one year, each of the older buildings units spent $8,176 in heating and electricity costs, while the new buildings each spent $4,110 – a 58 percent decrease. Part of the cost reduction can be attributed to lower meter costs and lower utility rates. A report will be issued shortly describing the cost-effective energy reduction measures that AHA can use to lower the utility costs in its older units, building on the success of the new units.