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Duct Sealant Longevity

Can duct tape take the heat?

Duct leakage accounts for much of the inefficiency of residential forced air heating and cooling systems--the leakage of hot or cold air through ducts that means a waste of your energy dollars. Most duct leakage could be prevented with proper duct sealing. But field examinations of ducts often find their seals failing over time. To provide lab data about which sealants and tapes last, and which are likely to fail, we are conducting ongoing accelerated testing at Lawrence Berkeley National Laboratory Environmental Energy Technologies Division. 

Our major conclusion so far is that you should use anything but duct tape to seal ducts. (We've defined duct tape as any fabric-based tape with rubber adhesive.) The testing we've done so far shows that under challenging but realistic conditions, duct tapes fail. 

A report of of our research in Home Energy magazine provides more information on the longevity and failure rates of various duct sealing methods.


Articles by Berkeley Lab authors:

Media coverage

What are the alternatives to duct tape for sealing ducts? All the other tapes we tested that claimed to be useful on ducts passed our test. Tapes require a clean, smooth, dry set of surfaces to hold well. However, in most do-it- yourself installations, it can be difficult to find good conditions for use of tapes. Non-tape sealant approaches such as the use of mastics may perform better. 
A cutting-edge technique for sealing ducts is the aerosol sealant technology that was first developed at Lawrence Berkeley National Lab (see Aeroseal Inc. of Austin, Texas is working to commercialize this technology.
See for more information on ducts and the rest of LBL's Thermal Distribution research activities.

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Last Modified: March 10, 1999