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The new 2016 Title-24 Energy Code requires that new HVAC systems meet minimum airflow requirements and supply fan efficiencies.
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Studies have shown that a significant number of HVAC installations suffer from low airflow problems. Typically the main culprit is undersized return air design.
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The new T-24 energy code requires that the airflow at the return be verified by an independent HERS rater to meet the minimum requirement of 350 cfm per ton of A/C capacity. Installing HVAC contractors will need to make sure their installations will meet this minimum requirement, actually good duct design can result in up to 400 cfm per ton so the State minimum requirement of 350 cfm per ton is not overly restrictive.
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A second option, only available to systems without zoning dampers, is to size the return ducts according to the new Tables 150.0-C and D in the T-24 Efficiency Standards and then have a HERS Rater visually verify that the installed duct system meets the design criteria of those tables. see tables below:
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