A federal program that assists with the development of photovoltaic (PV) products for the U.S. building market has led to commercial development of factory-built modular homes with built-in PV systems. The program, Building Opportunities in the United States for Photovoltaics (PV:BONUS), initiated by the U.S. Department of Energy and the National Renewable Energy Laboratory, is a government/industry joint project with home builders, PV suppliers, building material manufacturers, utilities, engineers, and researchers. The aim is to help U.S. industry enter international competition for building-integrated PVs; assist utilities with demand-side management, load management, and transmission issues; and to benefit building owners and homeowners.

The PV-integrated modular homes were developed by Fully Independent Residential Solar Technology, Inc. (FIRST, Inc.), a non-profit research and development organization in Hopewell, New Jersey, that teamed with Bradley Builders of Philadelphia, and Avis America of Avis, Pennsylvania, a builder of modular manufactured homes.

The homes have 2kW rooftop PV systems, passive solar design, and solar hot water built in. Although there are variables based on the homesite location, the 2kW systems are sufficient to supply all the home's energy needs for a family with a relatively conservative lifestyle and energy-efficient appliances, says FIRST, Inc. president Lyle Rawlings. Some customization is possible, and some features are at buyer discretion, but Rawlings said the company makes available high-efficiency appliances, including refrigerators, dishwashers, washers and dryers, high-efficiency direct-current well pumps, and compact fluorescent lighting. Insulation consists of high-density fiberglass batts, with an option of additional extruded foam insulation, wall insulation that ranges from R-24 to R-28, and R-38 ceiling insulation. The homes can be either stand-alone or be utility-grid connected. Rawlings said most will probably be installed to function in both stand-alone and grid-connected modes, with the grid used for backup power when needed, and the home having the ability to sell excess power to the utility.

The homes do not resemble typical manufactured homes, and in fact do not appear different from site-built homes even though they are factory-built and shipped in up to four modules to the homesite. The solar homes come in three styles--Cape Cod, ranch, and two-story Colonial--and range from 1,350 ft2 to 2,500 ft2. They cost $50,000 to $78,000 delivered (depending on distance from the factory), with an additional $15,000 for the PV system. Additional costs are incurred for site assembly, finishing work and the cost of the lot, with an estimated total cost from $100,000 to $150,000. The homes qualify for financing with energy-efficient mortgages. Solar models are also being planned to sizes as small as 900 ft2, and as large as 4,000 ft2.

Thus far, two homes have been completed in Pennsylvania, and seven others are expected to be built and purchased by private parties. Some federal agencies have talked with Rawlings about purchases for employee residences at government sites. We're planning by 1995 or '96 to approach home sales in the hundreds, said Rawlings.

Other research and development projects being funded with assistance from PV:BONUS include development of lightweight, flexible roofing materials including PV shingles, and adapting PV to metal roofing products; PV modules that produce AC electricity; architectural PV glazing systems; and assessing the benefits of PV as a demand-side management option through research being done by the University of Delaware and Delmarva Power & Light Co. in Delaware.

-- Ted Rieger

Ted Rieger is a Sacramento, California-based freelance writer who specializes in energy issues.