Editor’s Note: This post is one of a series of technology spotlights that introduces common technologies used in U.S. Department of Energy Solar Decathlon team houses.

Structural insulated panels (SIPs) are prefabricated structural elements used to build walls, ceilings, floors, and roofs. Made of foam insulation sandwiched between two layers of structural board, SIPs provide a more airtight dwelling than a standard stud-frame house. This creates a quieter and more energy-efficient interior space. 

Various types of insulation can be used in SIPs in homes. The most common insulating material is polystyrene or polyisocyanurate foam. Foam insulation is added between two sheets of oriented strand board (an engineered wood product formed by layering strands of wood in specific orientations) to create an airtight seal. SIPs made with a straw-based core offer a sustainable alternative to foam insulation, but they are heavier and less efficient.

These structural insulated panels consist of foam insulation sandwiched between oriented strand boards. (Courtesy of Michael Bacchler)

SIPs can be made in various sizes and thicknesses to fit building specifications. In most cases, the manufacturer sends the panels directly to the job site. A major benefit of using SIPs in new house construction is the ease with which the panels fit together. Several U.S. Department of Energy Solar Decathlon teams enjoy this advantage during construction in the solar village.

SIPs cost about 15% more than standard stud frames. However, the tighter insulation can result in a 12%–14% decrease in energy bills. The initial investment usually makes the most sense for new construction efforts.

For More Information

Visit the Energy Savers website to learn more about SIP technology. Search the building envelope section of the Solar Decathlon 2009 product directory to find more information about the SIPs used by 2009 teams.

Alexis Powers is a member of the Solar Decathlon communications team.

Editor’s Note: This post is one of a series of technology spotlights that introduce common technologies used in U.S. Department of Energy Solar Decathlon team houses.

Homes generally rely on forced air systems, such as baseboard heat, for warmth in the winter. But for more energy-efficient and environmentally friendly heating, several houses built for the U.S. Department of Energy Solar Decathlon use radiant floor heating instead.

Radiant heating systems deliver warm air throughout a house in a silent, uniform, and energy-efficient way. Radiant floor heating is the most common application of this technology, although these systems are sometimes used to heat wall panels or even the ceiling.

In its Solar Decathlon 2002 house, the University of Delaware used a radiant floor heating system that consisted of fluid-filled tubing laid beneath grooved plywood and aluminum sheeting. (Credit: Chris Gunn/U.S. Department of Energy Solar Decathlon)

The most popular and cost-effective radiant heating device is a hydronic, or water-based, system, which circulates hot water through a series of tubes laid beneath the floor. When connected to a solar hot water system, hydronic radiant flooring can greatly reduce home energy bills.

Materials and installation costs for an 800-ft² home start at approximately $1,500.  

For More Information
To learn more about radiant heating products used in past Solar Decathlon houses, search the floor construction section of the Solar Decathlon 2009 product directory. Additional information about radiant heating systems is available from the Energy Savers website.

Alexis Powers is a member of the Solar Decathlon communications team.