Radiant Heating Panels Save Energy in Residential Building

In the U.S., the most common forms of residential heating systems are based on convection, using air as a heat transfer medium. Radiant heating systems are meant to transfer heat directly to a person or object in a manner similar to the way sunlight warms you on a cold day. Therefore, with radiant heating systems, people can be comfortable at room temperatures that are 6 to 8°F lower than with conventional forced air and baseboard heating systems. An occupied research home, owned by the National Association of Home Builders Research Center was selected for a case study of radiant heat panels. Built in 1990 it is a conventional two-story, 204 square meter (2,200 sq. ft.) home. The objective of the project was to assess the performance and comfort levels associated with the use of the Enerjoy radiant heat panel in comparison to conventional convection heating systems. Data on energy usage for both baseboard heat. Data on energy consumption during the radiant heating installation and heating with air-to-air heat pumps was collected via a monitoring and data acquisition system. The system obtained and recorded the data from stations located throughout the home. Energy consumption was lower with the radiant panels compared to the heat pump system or the baseboard heat system. One of the advantages of the radiant panels is that it is possible to set back the thermostat in any non-occupied zone. Occupant thermal comfort was also assessed. At the end of the study, both occupants stated their preference for the radiant heating system over conventional systems. Enerjoy was the recipient of a U.S. Department of Energy's Inventions and Innovations Program grant in 1982 to aid in the development and commercialization of this technology. As part of the grant application process, the National Institute of Standards and Technology conducted a favorable technical review of the technology.

Technical Data

The Enerjoy radiant heat panel is a solid state heating panel constructed of a micro-thin composition of conductive pigments and copper electrodes bonded between two layers of dielectric polyester film. This film is backed with one-inch thick six-pound density fiberglass board, faced with a texture coating and framed in aluminum. Its radiant output is 95% of its input energy. Panels are constructed to be mounted on the ceiling and have a nominal wattage of 50 Watts per .09 square meters (per square foot). Panels are also available in four voltages, 120v, 208v, 240v and 277v and are sized in .3 meters (1 foot) increments up to a maximum size of 1.2 by 2.4 meters (4 by 8 feet).

Energy Data

The estimated energy consumption resulting from heating with the radiant panel for a typical record year heating season in the home's geographic area is 7,229 kWh. This compared favorably to the heat pumps (10,764 kWh) and the electric baseboard system (15,107 kWh).

Economic Data

Typical Record Year Information: Heating Season Heating System

Radiant Panel Heat Pump Electric Baseboard estimated annual heating costs (at 0.055 USD/kWh) 398 USD, 592 USD, 831 USD.

Estimated annual savings from radiant panels Base 194 USD (33%), 433 USD (52%).

The estimated cost of the radiant heating system, less installation is 4,200 USD which includes the panels and the thermostats. As this innovative system becomes more commonplace, it is anticipated that its costs to the customer will decline. The payback period for this system will vary depending on whether it is installed as original equipment in new construction, as a substitution for a system that requires replacement, or as a retrofit to an existing system. Installing the system as part of new construction is less expensive since in can be installed by contractors already working on the site when other fixtures are being installed.

Contacts:

SSHC Richard. D. Watson 146 Elm St., PO Box 769 Old Saybrook, CT 06475 860-338-3848 860-388-0525 (Fax) http://www.sshcinc.com

NAHB Research Center Peter Yost 400 Prince George's Boulevard Upper Marlboro, MD 20772 301-249-4000 301-249-0305 (Fax) http://www.nahb.com

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