Title 24 compliance isn't finished at permit approval — it has a required field-verification layer that confirms specific claimed measures were actually achieved during construction, not just assumed on paper. Understanding exactly which measures trigger HERS (Home Energy Rating System) verification, and what each test involves, helps contractors plan these checkpoints into the construction schedule rather than treating them as a surprise near project completion.
Certain Title 24 compliance credits depend on installation quality that can't be confirmed just by reviewing plans — duct sealing, refrigerant charge, and insulation installation quality all depend on how well the work was actually performed in the field. HERS verification requires a certified rater to test and confirm these measures independently, which is what gives the claimed compliance credit its validity.
Where duct sealing is claimed as a compliance measure, a certified rater tests the installed duct system using a calibrated pressurization test, comparing measured leakage against the threshold claimed in the compliance documentation. This typically needs to happen before ductwork is covered by insulation or drywall for the most accurate and easiest-to-remediate results.
For split-system air conditioners and heat pumps, refrigerant charge verification confirms the system was charged to the manufacturer's specification — incorrect charge affects both efficiency and cooling capacity, which is why this is treated as a required field check rather than assumed based on installation alone.
QII verification confirms insulation was installed without significant gaps, compression, or misalignment that would reduce its effective performance below what's assumed in the compliance calculation. This typically involves a visual inspection protocol performed by the HERS rater at a specific point in construction, generally before insulation is covered by drywall.
Because these measures need to be checked at different construction phases — duct leakage and insulation installation before drywall, refrigerant charge once equipment is operating — HERS verification isn't a single final inspection but multiple coordinated checkpoints. Contractors who schedule rater visits around these specific phases, rather than treating verification as an end-of-project formality, generally avoid the scheduling conflicts and retests that come from catching issues too late.
Is HERS verification required on every Title 24 project?
It's required whenever the compliance calculation claims a measure that depends on field verification — which is common, since duct sealing and other verified measures are frequently used to help meet compliance targets.
What happens if a HERS test fails?
The specific measure needs to be corrected and retested before the project can proceed to final approval — for duct leakage, this can mean resealing connections; for insulation, correcting installation defects.
Can all HERS verification measures be checked in a single site visit?
Not always — since different measures are tied to different construction phases (duct and insulation before drywall, refrigerant charge with operating equipment), multiple visits are often needed.
Psychro.Pro helps California contractors identify which HERS verification measures apply to their project and plan rater visits around the right construction phases.Learn more.
