Duct sealing: A service that’s too often ignored
California’s 1998 Energy Efficiency Standards applies to all new low-rise residential buildings.
Many experts across the country have begun expressing their concerns about duct leakage.
- The Florida Solar Energy Research Center reports that air conditioning duct leakage is the single largest energy waste in Florida homes.
- A North Carolina-based building science specialist says duct leakage is a contributor in 60% to 80% of all the problem calls he receives.
- In South Carolina, an energy auditing-training firm says studies indicate as many as 85% of U.S. homes have leaky air-distribution systems.
- The National Association of Home Builders (NAHB) Research Center says heating and cooling costs can be reduced by as much as 20% to 30% by reducing duct air leakage and improving duct insulation.
- An Arizona hvac contractor’s website cites a Yale University study saying that 19 out of 20 homes tested have significant enough duct leakage to warrant repairs.
Duct leakage is apparently a serious and widespread problem, still largely unrecognized by many homeowners and even hvac contractors.
Utility Incentives“Duct sealing is a chicken-and-egg situation,” says David Brook, energy specialist with the Oregon State University Extension Energy Program.
“In a highly competitive market like residential hvac, contractors aren’t going to sell something that could cause them to lose a bid, and most utilities don’t offer duct sealing programs because there aren’t any skilled contractors.”
Still, better duct sealing seems to be beckoning some contractors with new business potential. New rules may force others just to do a better job.
In California, the new residential energy code will mean builders or hvac subcontractors must comply with specific means of insulating and joining all components of new-home hvac systems. If other states follow suit, contractors throughout the country may need to learn how to create and test tighter duct systems.
However, interest in duct sealing seems less intense than a few years ago, when many utilities were trying harder to manage demand. The utility firms paid or reimbursed homeowners at least part of the cost of duct sealing, so their hvac systems would be more efficient and not demand as much energy.
Some utilities continue to offer such incentives. After a homeowner pays an initial $30 for a leak check in a single-system residence ($15 more for each additional air handler), Florida Power & Light will rebate up to $154 per central a/c unit for an FPL participating contractor to fix systems in single family detached homes, or $40 for single-family attached and mobile homes.
The State of Oregon has a residential energy tax credit for tightening ducts in both new and existing homes, Brook reports. The program requires measurement before and after such action, using a duct tester such as the Minneapolis Duct Blaster or the “pressure pan” method with a blower door.
The standards also require verification that the hvac system does not create backdrafting. Training and certification are proficiency-based.
One of the chief trainers is Ted Haskell of the Oregon State University Extension Service Energy Program; another is a private contractor in Eugene, Ore.: Bruce Manclark, Delta-T HVAC.
Utilities in the Pacific Northwest have created a regional duct sealing certification program sponsored by the Northwest Efficiency Alliance. Standards will be similar to those for the Oregon state tax credit.
Duct leakage was the most cost-effective of any of the existing residential conservation opportunities the alliance considered funding, Brook told The News. However, marketing materials that have been developed for the program stress comfort and health and safety, he notes.
Dollars and SenseEven without utility company support, duct sealing on existing systems makes economic and often health sense for homeowners, says Jim Herritage, Energy Auditors, Inc., Mount Pleasant, S.C.
“Still, homeowners seem unwilling to invest $400 or $500 entirely on their own in such work,” he says, even when they’re shown that the process will quickly repay its cost in lower utility bills.
Herritage’s firm no longer conducts its “ailing ducts” workshops for utility reps and others.
“Most duct systems leak like sieves,” says Rick Safko, Indoor Ecology Associates, Ltd., Portland, Ore. His firm works either as an environmental consultant or general contractor on both commercial-industrial and residential systems.
“I ‘grew up’ in duct cleaning,” says Safko. He saw many types of duct damage and leakage during those years.