California HERS Testing for HVAC: What the Rater Actually Does

Looking for the complete picture? This post focuses on the HERS test mechanics. For the full California 2026 code reference covering Title 24, A2L refrigerant transition, SEER2/HSPF2 minimums, permits, HERS, and Manual J in one place, see our California HVAC Code 2026 pillar.

Most homeowners think the HERS test is a quality check the contractor runs after install. It is not. The HERS rater (as of January 2026, formally an ECC (Energy Code Compliance) Rater) is an independent third party who works for the State of California, not for your contractor. They show up after install, run a defined set of measurements on your duct system and refrigerant charge, and file a pass-or-fail certificate into a state registry that follows the property forever.

The contractor signs the install. The rater verifies it independently. The building inspector checks code compliance separately. Three different people, three different domains, all required for a legal HVAC change-out in California.

What HERS is and what it tests

The acronym is Home Energy Rating System. California adopted it as the verification regime now codified at Title 24 Part 6, administered by the California Energy Commission. Effective January 1, 2026, the field verification and diagnostic testing rules moved out of the HERS regulation and into the new Energy Code Compliance (ECC) Program. The tests are unchanged; the paperwork and the registry got renamed. Most contractors and homeowners still say “HERS test” because that is the term that has stuck for twenty years.

For a residential HVAC change-out, the rater is verifying four specific items defined in the 2025 Reference Appendices RA3:

• Duct leakage to outside. A duct blaster fan pressurizes the duct system and CFM of leakage is measured at a calibrated test pressure.
• Refrigerant charge verification. Subcooling method for systems with TXV or EEV metering devices, superheat method for fixed-orifice systems. Manufacturer-specific targets, adjusted for measured indoor and outdoor wet-bulb / dry-bulb conditions on the day of the test.
• Airflow at the air handler. Actual delivered CFM versus design (350–400 CFM per ton is the typical residential window).
• Fan watt-draw. Watts the blower pulls at the measured airflow. The cap forces properly sized ductwork: you cannot bury an undersized duct system by throwing a more powerful fan at it.

SEER2 and HSPF2 verification are read off the AHRI matchup certificate the contractor pulled at quote time, which the rater confirms matches the equipment actually installed. If you were quoted a Carrier Infinity 26 condenser matched to a specific FE5A coil, a Trane XV20i with the 4TXC coil, or a Daikin Fit DZ20VC with its inverter air handler, the rater checks serial numbers against the AHRI line item. Substitutions without a re-issued AHRI match fail the inspection.

When HERS / ECC testing is required

Almost every residential HVAC change-out in California triggers HERS verification. The specific triggers, in plain language:

• New condenser or heat pump outdoor unit, refrigerant charge and airflow tests required, duct leakage required if the air handler or ductwork is touched.
• New air handler, coil, or furnace, airflow, fan watt-draw, and duct leakage required.
• Any new ductwork, including replacing more than 40 linear feet of existing duct, duct leakage test required.
• Any opening of the refrigerant circuit (line set replacement, condenser swap that breaks brazed joints), refrigerant charge verification required.

The narrow exceptions are like-for-like sealed-system swaps that do not open refrigerant lines or modify ductwork, blower motors, contactors, capacitors, thermostats. A condenser replacement absolutely does trigger HERS. If a contractor tells you a $9,000 change-out does not need HERS testing, that is a red flag; call your local building department before you sign. Full code-side picture in our Title 24 compliance guide.

Tests performed and pass/fail thresholds

Thresholds below are the typical residential change-out path under the 2025 Energy Code; specific exemptions can shift the numbers, and your rater confirms the path before testing.

Duct leakage to outside

The duct blaster pressurizes the system to 25 Pa relative to outside; CFM of leakage is measured. Full-system replacements with new ducts allow leakage at or below roughly 5–6% of nominal airflow [VERIFY: confirm exact 2025 Energy Code threshold for change-out path]. Existing-duct verification paths allow higher leakage with documented sealing improvements over baseline.

Practical translation for a 4-ton system at 1,600 CFM nominal: somewhere around 80–100 CFM of leakage is the pass/fail boundary. A single unsealed flex-to-collar transition can cost you 20–30 CFM. This is why competent installers spend real time at the duct connections with mastic, not the foil-tape-only approach that was acceptable in 1995.

Refrigerant charge

Rater measures liquid and suction line temperatures and pressures, calculates subcooling (TXV/EEV) or superheat (fixed-orifice), compares to the manufacturer’s target adjusted for measured indoor and outdoor conditions. Typical tolerance is roughly ±3°F on subcooling for variable-capacity inverter systems. R-454B (standard on 2025-and-later equipment) has its own charge tables; the rater uses 2025 service literature, not R-410A reference values.

Airflow and fan watt-draw

Airflow at the indoor coil should land between 300 and 450 CFM per ton, most installs targeting 350–400. Fan watt-draw caps vary by system class; for a typical residential ECM blower the target is roughly 0.45 watts per CFM. A fan pulling 0.7 watts per CFM at rated airflow is screaming “duct system is too restrictive,” and the rater fails it accordingly.

Who pays for HERS testing

Under the regulation, the homeowner is responsible for the rater fee. In normal practice, the contractor schedules the rater and includes the fee as a pass-through line item on the install invoice. Typical 2026 California fees:

• Single-zone residential split system, single-story, 1,500–2,500 sq ft: $250–$450
• Multi-zone or two-story with longer duct runs: $400–$650
• Whole-home heat pump retrofit with multiple indoor units: $550–$900
• Re-test after a fail: $150–$300 (often eaten by the contractor if the failure was a workmanship issue)

We line-item the HERS / ECC fee on every install quote so the homeowner sees it. Workmanship-grade failures (sealing missed a joint, charge off-spec at commissioning) are on us, we cover the re-test. Failures outside the install scope (existing duct system substantially worse than disclosed at quote) get negotiated, usually splitting the re-test cost and rewriting scope. Get this in writing before you sign.

HERS rater independence: the rule that does the work

The most important thing about HERS testing: the rater cannot be your contractor or the contractor’s employee. This is hard regulation under Title 24 Part 6 and Title 20. The rater cannot have a financial interest in the installing contractor’s business and cannot recommend products or services they are verifying. Building officials can prohibit a specific rater from operating in their jurisdiction if independence is in question.

The current California-approved provider organization is CHEERS (ConSol Home Energy Efficiency Rating System). CalCERTS, the former second major provider, ceased HERS operations on August 2, 2024 and the residential registry has consolidated under CHEERS [VERIFY: confirm current provider list before next quarterly content refresh; CEC rulemaking is ongoing].

If a contractor tells you “we’ll have our HERS guy come out,” ask for the rater’s ECC certification number and look it up on the CHEERS public directory at cheers.org. We use a working rotation of independent raters across LA County, Orange County, the SGV, San Bernardino, Riverside, and Ventura County. Each has their own LLC and their own E&O insurance. They fail our installs when the work deserves to be failed; that is the point of the rule.

Honest pushback: the duct-leakage threshold is achievable on a competently installed system. If your contractor is dodging HERS or telling you that you do not need it, that is a red flag about the install quality, not the rule. A good installer wants the test because the certificate proves the work was done right.

HERS test versus building permit final inspection

These are two separate inspections homeowners frequently confuse. Both are required.

The building department inspector (LADBS in the City of LA, county building departments elsewhere) checks code: electrical disconnect placement and gauge, gas line bonding and sediment trap, condensate drain routing, equipment mounting and clearances, line set protection, combustion air. They do not test duct leakage and do not check refrigerant charge.

The HERS / ECC rater tests the four energy-performance metrics above and files the certificate to the state registry. They do not check electrical disconnects or gas bonding and cannot sign off on code compliance.

Both have to pass for the permit to close. We file the permit, schedule both inspections, and deliver the closeout package: city sign-off, ECC certificate (formerly CF-3R), AHRI match, equipment serials, warranty registration. Permit detail in our HVAC permits guide.

What happens when a system fails the test

Pass rates on competently installed work are high: in our coverage, around 85–90% of our installs pass on the first attempt, with the bulk of failures concentrated in older homes with marginal existing ductwork.

The rater issues a written deficiency notice listing the failed measurement and actual value. The contractor has 30–60 days (varies by jurisdiction) to correct and re-test. Common fixes in order of frequency: additional mastic sealing at flex-to-metal transitions, refrigerant charge adjustment after re-commissioning, replacement of damaged flex sections, occasionally an airflow adjustment by removing a restriction or upsizing a return.

Re-test cost depends on cause. Substandard install (we missed a joint, set charge off-spec) the contractor eats the re-test. Pre-existing duct system worse than disclosed at quote (the original 1972 ducts testing at 25% leakage) gets negotiated, usually a split or a change order for additional sealing. Worst case, an install with fundamentally undersized ductwork has to be partially redone — rare, almost always when a contractor cut corners at design, and a reputable contractor catches it at the quote walk-through.

The provider data registry: why HERS does not go away

The CHEERS registry stores ECC certificates by property address. Records are accessible to building departments, utility programs (TECH Clean California rebates pull from this registry), real estate inspectors at sale, and the homeowner directly. Once filed, the certificate follows the property.

This is why you cannot “skip” HERS later. Three years from now, when you list the house in Manhattan Beach or refinance in Pasadena, the buyer’s inspector or the lender’s appraiser will pull the registry and find the missing certificate. The seller has to either retroactively test (often a fail) or disclose the deficiency as a closing credit. We see this regularly when called to evaluate older work. Fix cost ranges from $400 for a re-test on a marginal pass to $1,800+ for a duct seal-up and re-test.

Composite example: HERS test on a Manhattan Beach AC replacement

A 2,400 sq ft 1972 single-story ranch in Manhattan Beach, late summer 2025. Homeowner replacing a 19-year-old gas furnace and 14-SEER condenser pair with a 4-ton variable-speed Daikin Fit DZ20VC heat pump matched to its inverter air handler. Original R-6 flex on metal trunk, three transitions showing seal degradation at the inner core.

Our pre-rater work: re-sealed seven trunk-to-branch transitions with mastic, replaced the three worse flex sections, sealed the supply plenum-to-trunk joint that had been foil-taped only. Commissioned on a moderate 78°F day with the manufacturer’s R-454B charge tables. Our own pre-test duct leakage reading: 4.1%.

Rater showed up two weeks later on a 92°F afternoon, attic at 128°F. Duct leakage 4.6%, pass. Subcooling 11.5°F against a manufacturer target of 12°F ± 3, comfortable pass. Airflow 1,560 CFM at 4 tons (390 CFM/ton), inside the window. Fan watt-draw 0.43 watts per CFM, under the cap. Certificate filed in CHEERS, closeout package delivered. 75 minutes on site. Rater fee on the invoice: $385.

The rater is not adversarial when the install was done right. They run objective measurements against a code-defined standard, and a contractor who has commissioned properly walks in expecting to pass.

How long the visit takes and scheduling

Residential split-system tests run 60–90 minutes on site. Multi-zone systems can run 2–3 hours. The rater files the certificate within a few business days. We schedule the rater immediately after install completion; the test typically lands 1–3 weeks later. We rotate among two or three independent ECC raters across our coverage for AC installation and furnace installation work, so we are not bottlenecked on any single one. For emergency replacements heading into a heat wave, we can usually get a rater out within 5–7 days.

What to ask before you sign

1. Confirm the HERS / ECC rater fee is line-itemed in the quote, not buried in “permits and fees.”
2. Ask for the rater’s name and CHEERS certification number; look them up in the CHEERS public directory.
3. Get re-test responsibility in writing, workmanship failures should be the contractor’s cost.
4. Confirm the closeout package: building final, ECC certificate (formerly CF-3R), AHRI matchup, equipment serials, warranty registration.

If a contractor pushes back, you are looking at the wrong contractor. All of it is standard for a licensed C-20 install.

How we work the rater into our process

We pull the permit in your name with our license listed, schedule the rater after install completion, and hand over the closeout package within 7–10 days of the test passing, everything you need for sale, refinance, warranty claim, or utility rebate paperwork. Same process across the West LA basin, the SGV from Pasadena through Diamond Bar, Orange County, the Inland Empire, and the Ventura coast. CSLB #1138898 (C-20).

Related reading: Title 24 Part 6 in detail, HVAC permits in Los Angeles, AC installation, furnace installation, heat pump installation.