March 5, 2001

 
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Max Sherman, who authored this article, is a researcher in Lawrence Berkeley National Laboratory's Environmental Energy Technologies Division.

There is a huge energy hog in the vast majority of our Californian homes. This culprit wastes 20 to 40 percent of our heating and cooling energy but remains hidden from view. Well over a billion dollars per year is currently being lost through leaky heating and cooling ducts.

The potential savings from sealing residential ducts in California adds up to $1-2 billion per year. This would be enough to fund the current utility rescue plan with enough money left over to build an extra gigawatt of generation -- each year.
 

Studies have shown that duct systems in the state typically leak over 20 percent. Since most ducts are installed in spaces like attics, the energy loss is very large. Statewide, the potential savings from improving ducts is between 1-2 gigawatts (GW) of electricity alone. No single efficiency improvement has equivalent savings potential. Putting this into perspective, those trying to steer California through the ongoing electricity crisis estimate that we need to save some 3.7 GW this upcoming summer.

The potential savings from sealing residential ducts in California adds up to $1-2 billion per year. This would be enough to fund the current utility rescue plan with enough money left over to build an extra GW of generation -- each year.

Unlike many of the other approaches to fending off the energy crunch, duct improvement is a win-win-win situation. Not only are energy use and energy costs reduced, but people will actually see an improvement in comfort as that corner bedroom now will get adequately heated and cooled. Unlike behavioral changes that go away as the crisis recedes, the savings from duct efficiency improvements will last.

Happily for Californians, the technology to seal ducts within the attic, walls, and basements of their homes already exists. No, not duct tape, which has been proven to be ineffective at sealing ducts, but rather an aerosol sealant mechanism that seals ducts from the inside, like the stuff you put in your carís radiator to seal leaks.

Starting in 1990, Lawrence Berkeley National Laboratory was funded by the state's utilities through the California Institute for Energy Efficiency to develop methods for reducing energy lost through ducts. Over several years, an aerosol sealant system was developed by the Lab, was patented, and has been licensed to a commercial company, Aeroseal Inc. Aeroseal has commercialized the technology and franchises it to contractors involved with heating and air conditioning who provide the service to the public.

Although the number of contractors doing this work is growing -- Aeroseal lists certified contractors on its website -- right now there are not nearly enough to make a big dent in Californiaís energy problem. Currently thousands of duct systems can be sealed each year, but the need is for millions.

To get more penetration of duct sealing in the state, the public first must become aware of the option. Incentives for contractors to invest in the technology and the necessary equipment also would make a dramatic difference.

There are other ways to seal ducts.  However, none are as cost-effective or contain as much built-in quality assurance as the aerosol sealant technology.

Additional information:

IN A TYPICAL RESIDENCE,  DUCT LEAKS RESULT IN ENERGY LOSS OF 20 TO 40 PERCENT