Public Release: 

Leaky ducts in HVAC units drive up energy costs for Louisiana homeowners, researchers say

Report says problem widespread but easily fixed for big savings

Louisiana Tech University

RUSTON, La. - Some Louisiana Tech researchers are saying that the cost of energy loss to Louisiana homeowners is not cool at all.

The researchers have released findings on air-conditioning duct leakage in 55 Louisiana homes in a report titled: "Testing HVAC Duct Leakage in Existing Residential Buildings in North Louisiana." The heating, ventilation and air-conditioning study was funded by a grant from the Louisiana Department of Natural Resources.

"The basic line of thought is that the duct leakage is so huge in our state and so cheap to fix," said Norman M. Witriol, a physics professor with Tech's Trenchless Technology Center. "The first step is to get some type of estimate to see what is going on in your house; the second thing is to see how it can be repaired."

In the report, duct leakage in the targeted homes averaged 29 percent. By contrast, 5 percent leakage is the maximum acceptable for new homes in Florida. Researchers also estimate that in many Louisiana homes, duct leakage accounts for more than 70 percent loss of the efficiency of residential air-conditioning systems.

Witriol said the implication is that, on average, duct leakage in Louisiana is more important to air-conditioner efficiency than is the efficiency rating of the HVAC equipment.

The Tech research group sees the new information as particularly meaningful in light of current House-Senate conference committee meetings concerning the National Energy Bill: On the table is a provision to allow a $2,000 tax credit for energy efficiency improvements to homes and to establish how such improvements should be confirmed.

Witriol said committee debate is sure to bring homeowner energy issues to the forefront, an outcome he sees as positive: "I think it's good for the average Louisiana citizen to start looking at their system and saying, 'Do I have this type of problem, and what can we do about it?'"

To find out more about the Home Energy Rebate Option and locate certified raters, go to the DNR Web site ( and click in the frequently accessed programs.

For additional information, or a PDF copy of the report, contact Witriol at 318-257-4670 (work), 318-237-0959 (cell), or; or contact Myron Katz, president of the National Energy Raters Association and a consultant with Wisznia Associates in New Orleans, at 504-343-1243 (cell) or

Other researchers who were involved in the project are: Raja Nassar, a professor of mathematics and statistics, Tech; Jinson J. Erinjeri, a graduate research assistant, Tech; and Robert McKim, now a professor of civil engineering at Western Kentucky University.


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