Mention Title 24 to California contractors, and often you're met with a groan or an eye roll. The "Energy Efficiency Standards for Residential and Nonresidential Buildings" (Title 24) were established in 1978 in response to a legislative mandate to reduce California's energy consumption. The standards are updated periodically to allow consideration and possible incorporation of new energy-efficiency technologies and methods.

On Oct. 1, those standards were updated again. Starting on that date, homeowners in certain climate zones must have their ducts tested for leaks and repaired whenever they have a heating or cooling coil, air handler, or outdoor condensing unit replaced. After the contractor tests and fixes the ducts, a third-party verifier must check to make sure the duct sealing has resulted in less than 15 percent leakage.

There are exceptions to the standard, however, which may cause some confusion for many contractors. That's because there are 16 climate zones in California (per the California Energy Commission), and the requirements for each zone vary. In some zones, it's not necessary to seal the ductwork if a high-efficiency (92 percent-plus) furnace is installed, and in others a high-efficiency furnace and a 14-SEER air conditioning unit must be installed before the duct sealing requirement is waived. In most coastal zones, no duct sealing is required at all.

For contractors whose businesses take them into two or more climate zones, there is a real possibility that the requirements for duct sealing may change from one side of the freeway to the other. The good news is that the installation of high-efficiency equipment eliminates the duct sealing requirement and third-party verification in all of California's climate zones.

Figure 1. This map of California shows the 16 different climate zones that are designated by the California Energy Commission. The climate zones are based on energy use, temperature, weather, and other factors. They are basically geographic areas that have similar climatic characteristics.

Testing And Sealing Requirements

Everyone agrees that leaky ductwork is a huge problem that results in far too much energy being wasted. Field research in California shows that ducts in existing homes allow about 30 percent of the heated or cooled air to leak out before it reaches the rooms it was intended to condition. But many contractors already knew that, including Andy Bogdonoff, owner, Andy's Heating, Yuba City, Calif.

"When we change out a system, we have to tight seal the duct system," said Bogdonoff. "We've offered that option for the last 10 or 15 years anyway. It's always a good idea, but now it's no longer optional. It's mandated."

In the updated Title 24, changeouts in existing low-rise residential buildings in climate zones 2 and 9 through 16 (see map in Figure 1) require contractors to use duct pressurization equipment to test the leakage of the duct system when 40 linear feet or more of the duct system is in unconditioned space.

Contractors must comply with one of the following four duct sealing requirements:

  • The measured duct leakage must be less than 15 percent of fan flow.

  • The measured duct leakage to the outside must be less than 10 percent of fan flow.

  • The measured duct leakage must be reduced by more than 60 percent relative to the measured leakage prior to the installation or replacement of space conditioning equipment, and a visual inspection, including a smoke test, must demonstrate that all accessible leaks have been sealed.

  • If it is not possible to meet the duct requirements above, all accessible leaks must be sealed by the contractor and verified through a visual inspection and a smoke test by a certified home energy rater (HERS).

    Per the standard, the ducts must meet duct sealing requirements and be insulated to R-4.2 (climate zones 6, 7, and 8), R-6 (climate zones 2 and 9 through 13), or R-8 (climate zones 14, 15, and 16). If the installed ducts form an entirely new duct system, the measured duct leakage must be less than 6 percent of fan flow. If the installed ducts are an extension of an existing duct system, they must meet one of the four leakage requirements previously listed.

    To ensure the mandatory participation in this program, certification by a HERS inspector is necessary in order to close out a building permit. In California, a building permit is required any time a serialized piece of equipment is installed. After Oct. 1, if a component is replaced, a HERS representative will have to certify that the duct system has less than 15 percent leakage.

    The problem just may be that there aren't enough HERS inspectors to certify the systems right away. "We need that certification to close out the building permit, and most homeowners don't feel comfortable paying the bill until the building permit is closed out. That's understandable. But it might take two to four months to get the system certified. We just don't know how this is going to play out," said Bogdonoff.

    The good news is that once a duct system has been sealed and certified, the system does not need to be recertified if future replacements are made. The bad news is the additional cost for homeowners. Bogdonoff estimates the certification process will add $300 to $500 to each job, which may lead homeowners to look for alternatives.

    Andy Bogdonoff stated that the 92 percent efficient furnaces have always sold well in his area but that the new changes to California’s Title 24 should cause sales to go through the roof.


    Fortunately, high-efficiency furnaces and air conditioners may be installed in lieu of duct sealing. For example, in climate zones 2 and 12, the contractor may eliminate the need for duct sealing or HERS verification if he replaces an existing air conditioner with a 13-SEER-plus unit and the existing furnace with a 92 percent or higher furnace.

    Bogdonoff is already a proponent of high-efficiency furnaces (he installs primarily Westinghouse), and he sees this mandate as making this part of his business even stronger. "I think the 92 percent market is going to absolutely explode," he said.

    "Right now, builders are only looking at higher-efficiency air conditioning units, but sooner or later they'll have to look at the furnaces as being the most cost-effective measure."

    That's especially true given the sharp hikes in natural gas prices that consumers can expect to see this year. Indeed, it's estimated that home heating bills in Northern California will jump by an estimated 40 percent this winter.

    "Homeowners are seeing an increase in their utility bills, and that's what they're concerned about," said Bogdonoff.

    As for the new changes to Title 24, Bogdonoff is not too concerned, because he's well versed in all the rules and regulations. Other contractors may have problems, though.

    "You have to be good at what you do. Nothing really changes for the little guy working out of his house, because he doesn't sweat the small stuff, and he tries to fly under the radar. We expect about half our competitors up here to not take out building permits in order to get around the new rules."

    That's just not an option for Bogdonoff, who decided to take the training to become a HERS inspector. For him, quality means everything, which is probably why he's been in business over 35 years and has a loyal (and large) customer base.

    Publication date: 11/21/2005