Radiant Barriers: A Question and Answer Primer
To most homeowners, attic radiant barriers are a new energy conservation concept; many of them have questions about how radiant barriers work and how to use them. Herein are answers to some of the most commonly asked questions. Also included are recommended ways to install radiant barriers in existing attics and new homes.
Attic radiant barriers are an inexpensive but effective way for Sunbelt homeowners to save energy and money. While they are not a new concept, radiant barriers have only recently been proved effective for energy conservation.
Manufacturers are continuing to improve radiant barrier materials, which are becoming widely available throughout the southern states. A radiant barrier may be installed in an existing attic or during construction of a new home. Both are relatively easy procedures.
Table of Contents:
• What is a radiant barrier?
• What are the benefits of radiant barriers in attics?
• How do radiant barriers "block" heat transfer?
• How much can radiant barriers save?
• Are claims of greater savings untrue?
• What kinds of radiant barrier materials are available?
• Which material is best?
• What does a radiant barrier cost?
• My material has only one foil side; should the foil face the roof?
• How should I install a radiant barrier in my attic?
• Does the radiant barrier have to be airtight in order to work?
• Can't I just roll the material out on top of the insulation?
• Will foil-faced batt insulation work as a radiant barrier?
• Will heat build up in the roof and damage my shingles?
• What about my shingle warranty?
• Can I just roll the material out on the roof before reshingling?
• What's the easiest installation method in new construction?
• What else can I do to decrease heat gain through my attic?
• When will I see a payback from an attic radiant barrier?
Acknowledgment:
Publication of this document was supported in part by Florida Power & Light Company.
Selected References:
Danny S. Parker , Jeffrey K. Sonne , John R. Sherwin “ Flexible Roofing Facility: 2002 Summer Test Results”, Prepared for: U.S. Department of Energy Building Technologies Program, July 2003
Parker, D.S., J. R. Sherwin and M. T. Anello, January 2001. " FPC Residential Monitoring Project : New Technology Development — Radiant Barrier Pilot Project," Contract Report FSEC-CR-1231-01 , Florida Solar Energy Center, Cocoa, Florida.
Danny Parker, Robin Vieira “ Priorities for Energy Efficiency In New Residential Construction in Florida,” February 2000, Florida Solar Energy Center, Cocoa, Florida.
Parker, D., Sherwin, J., "Comparative Summer Attic Thermal Performance of Six Roof Contructions," The 1998 ASHRAE Annual Meeting, Toronto, Canada, June 20-24, 1998.
Parker, D., Sherwin, J., Sonne, J., Barkaszi, S., Floyd, D., Withers, C., "Measured Energy Savings of a Comprehensive Retrofit in an Existing Florida Residence," For the Florida Energy Office, December, 1997
Fairey, P., "Designing and Installing Radiant Barrier Systems," FSEC-DN-7, Florida Solar Energy Center, Cape Canaveral, FL, 1984.
Fairey, P., "Effects of Infrared Radiation Barriers on the Effective Thermal Resistance of Building Envelopes," proceedings of the ASHRAE/DOE Conference on Thermal Performance of the Exterior Envelopes of Buildings II, Las Vegas, NV, December 1982.
Fairey, P., "The Measured Side-by-Side Performance of Attic Radiant Barrier Systems in Hot-Humid Climates," proceedings of the 19th International Thermal Conductivity Conference, Cookeville, TN, October 1985.
Fairey, P., "Radiant Energy Transfer and Radiant Barrier Systems in Buildings," FSEC-DN-6, Florida Solar Energy Center, Cape Canaveral, FL, 1984.
Joy, F.A., "Improving Attic Space Insulating Values," ASHAE Transactions, Vol.64, 1958.
Levins, W.P., and M.A. Karnitz, "Cooling-Energy Measurements of Unoccupied Single-Family Houses with
Attics Containing Radiant Barriers," Oak Ridge National Laboratory, Contract Report, DE-ACO5-840R21400, July 1986.
"Radiant Barriers: How They Work and How to Install Them," videotape, FSEC Producer, Cape Canaveral, FL, 1986.
Van Stratten, J.F., Thermal Performance of Buildings, New York: Elsevier Publishing, 1967.
©Copyright 2005 by Florida Solar Energy Center
