Article published in “Automated Builder Magazine,” October 2003.

Zero Energy Manufactured Home

By Michael Lubliner and Andrew Gordon, Washington State University Energy Program

Photo 1. Zero Energy Manufactured Home at the Nez Perce Fish Hatchery, near Lewiston, ID.

The nation’s most energy efficient manufactured home is sited at the Nez Perce Tribal Fish Hatchery, near Lewiston Idaho. Construction of the Zero Energy Manufactured Home was funded by the Bonneville Power Administration, and coordinated by the U.S. Department of Energy funded Building America Industrialized Housing Program (BAIHP). BAIHP researchers worked closely with the Nez Perce Tribe, Kit Manufacturing (manufacturer) and Clearwater Homes (dealer).

The goals of the Zero Energy Manufactured Home project were to demonstrate the technical feasibility of innovative energy features, and evaluate costs, energy savings and other benefits. The home is now tribal housing for operations staff at the hatchery.

Mike Klingner, general sales manager of Kit Manufacturing, said “[we] felt the project was enlightening in many ways.” While Kit Manufacturing has experience building energy-efficient manufactured homes through the Northwest’s Super Good Cents/Energy Star program, the Zero Energy Manufactured Home project “took it to the next level. It brought Kit a greater awareness of energy-efficient building techniques to those of us who participated in the program.”

According to the retailer, Christy Skinner, co-owner of Clearwater Homes, in Orofino, Idaho, the home wasn’t difficult to install. “There were a few minor differences in the insulation required between the sections, but it wasn’t more involved than the average installation.” Clearwater also installed a second home adjacent to the Zero Energy Manufactured Home, built to Super Good Cents standards and identical in layout, but without the additional technologies used in the Zero Energy Manufactured Home. This home will be used as a control in evaluating the energy savings in the Zero Energy Manufactured Home.

In keeping with the ongoing BAIHP efforts to form partnerships with builders and suppliers that result in increased numbers of energy efficient homes, BAIHP staff recruited over twenty suppliers of innovative energy efficient measures for inclusion in the Zero Energy Manufactured Home. These measures include:

• Icynene® insulation in the wall, floor and roof. This expanding foam product achieves excellent insulating value, has no voids or compression (common to fiberglass batts) and provides excellent air-sealing. According to Mike Klingner of Kit Manufacturing, “[Icynene®] can help to gain higher walls and thinner floors at superior R-values.” Klinger believes that integrating the foam insulation into the plant process would make it more attractive and lower the cost.
• The solar energy system, consisting of:
  • 4.2 kW (28) solar photovoltaic panels, which produce electricity to the home and/or roll back the meter, sending power back to the utility grid.
  • A “solar-ready” option package, providing a lower cost, HUD-approved solar system requiring no roof penetrations. It includes electrical and plumbing chases for simpler after-market installation of solar equipment.
  • A closed loop, two-tank solar water heating system, designed to provide 60 percent of the hot water for a typical two-bedroom home.

    Photo 2. Application of Icynene® insulation on Zero Energy Manufactured Home.

• Sun-tempered solar design, which moves existing window area to the south side, adjustable awnings optimize solar energy in winter/shade in summer, and insulated curtains/blinds reduce heat loss/gain.
• Energy Star© windows, appliances, exhaust fans, and lighting.
• An Insider heat pump, with no outside unit, so that no HVAC contractor is needed. The Insider uses crawlspace air for heat exchange; since the crawlspace is warmer in winter and cooler in summer than outside air, heat pump efficiency is improved.
• A mastic and screw-in tab-less riser duct system, reducing branch and trunk duct registers, and resulting in very low duct leakage and lower material and labor costs.
• R8 crossover ducts, with strong inner liners and plastic elbows that eliminate duct crimping and ensure proper long-term airflow.

The solar energy package is expensive, about $30,000. However, the package is cost-effective today in remote areas where utility electric service is unavailable or prohibitively expensive.

The other upgrades added about $4 per square foot, or approximately $6,400, to the cost of the house ($47 more per month on a 30 year 8 percent mortgage). Much of this added cost is offset for homebuyers in lower electric bills, higher resale value, potential government and utility incentives, and an improved indoor environment. It is expected that costs will come down as these technologies become standard or frequently ordered options.

 Testing at Kit Manufacturing and on-site at the hatchery indicate that the air leakage in the envelope and ducts of the Zero Energy Manufactured Home are the lowest yet seen by BAIHP staff. The energy performance of both the Zero Energy Manufactured Home and the control home will be monitored over the next year. Results of the monitoring will help the Bonneville Power Administration, BAIHP staff, and the manufactured housing identify the cost-effectiveness and viability of the innovative construction measures.

Project results and updates can be found at: www.bpa.gov/Energy/N/energy_tips/zemh. For more information, contact Michael Lubliner, WSU Energy Program, at 306-956-2082 or lublinerm@energy.wsu.edu.

More information on the Building America Industrialized Housing Partnership can be found at: http://www.fsec.ucf.edu/Bldg/baihp.